Which printer is right for you?

Understanding the choices

We've all seen the commercials that suggest asking your doctor whether a certain prescription is right for you. Wouldn't it be nice if we always had someone to consult when making important decisions who could help us determine the right path for us? Choosing a printer is important to your enjoyment of digital photography but can be a confusing process simply due to the number of models available and the different features offered. Many people try their local electronics or computer super store, but the "consultants" in the printer section often seem to know more about the "extended warranty" that they try to sell you than the printers themselves! This short article will give you some tips on hunting for the right printer for your needs. While the article covers only the basics, it should give you the foundation to be able to ask the right questions and do the right research to decide on your choice of printer for printing photographs at home. Note that this article addresses printing of photographs (not text) and also assumes that you have already weighed the costs/benefits of printing your digital photos at home versus online (or at stores like Wal Mart) and you have decided to print at home.

Understanding the technology and limitations

There are many types of photo printers on the market, including inkjet, dye sublimation (dye sub), color laser, and even printers that use a chemical process similar to traditional photo "kiosks" at photo outlets. By far the most cost effective and most popular models for home printing are the inkjets and the dye subs, so we'll focus on those.

• Inkjets: Color inkjet printers have been around for many years and like the internal combustion engines that run our cars, trucks, and SUV's, they aren't the most efficient animals in the world but they are so accepted and have been around so long that they have been perfected to the point that they really do the job well. Today's top quality photo inkjets offer a wide color range (color gamut), super high resolution, and can even be obtained in archival form for prints that will most likely outlast you! Inkjets work by "spitting" tiny dots of colored ink in a pattern so fine that your eyes cannot detect the dots.

• Dye subs: Dye sub printers have been around a long time too and have also been perfected to efficient photo printing machines. Dye sub printers work by "melting" off a layer of dye from a ribbon (basically a roll of plastic) onto the paper as it passes by a heater. Dye subs are considered "continuous tone" because each "dot" produced on the page can be any (arbitrary) color. Dye subs don't use dot patterns to fool the eye into seeing a particular color, rather, they place the exact color needed at each location so that the final print is dot free.

Advantages and disadvantages of inkjets versus dye subs

We cannot mention every possible advantage/disadvantage when comparing inkjet and dye sub printers but the following list hits the major points that will apply to most people printing photos at home.

Inkjet Advantages:

• Very precise and sharp edges

• Latest models offer incredible detail that exceeds most dye subs

• Variety of papers/surfaces available such as matte, luster, glossy

• Not locked in to one manufacturer's paper

• Archival inkjets can be found that produce prints w/long life

• Most can print on many different surfaces designed to accept ink including CD's, CD inserts, envelopes, etc.

• Have a considerably larger color gamut and usually produce more vivid photos than dye subs

• Easier to obtain large format inkjets that can print 11x14, 13x20 sizes, or larger

• Inkjet printing is often cheaper than dye sub printing

Inkjet Disadvantages:

• Often much slower than dye subs

• Most non-archival inkjets produce prints that fade a little (sometimes a lot) faster than dye sub prints

• Print heads sometimes clog and require cleaning or even replacement

 

Dye Sub Advantages:

• Very fast

• Relatively maintenance free

• Smooth with no dot patterns visible, even under magnification

• Produce excellent shadow detail in dark areas where some inkjets may be "blotchy"

• Prints are usually more durable and more waterproof than inkjet prints

• For many viewers, dye subs simply produce photos that look and feel more like real photographs due to the smoothness of the prints and the absence of visible dot patterns

Dye Sub Disadvantages:

• Consumer level models often smear high contrast edges (like a black square on a white background) to some degree, making charts, graphs, and line art look a bit less "precise"

• Dye sub prints typically only last as long or slightly longer than a good non-archival inkjet printer and are generally not considered "archival"

• Paper type selection is very limited and while dye subs produce excellent glossy photos, most fall behind or do not even offer the option of matte prints

• Must use an entire page and an entire page worth of ribbon even to print one small wallet size photo because dye subs are "page at a time" and pages cannot normally be fed through the printer twice to fill more of the page as they can in inkjets

• Dust can sometimes get inside and cause vertical scratches on prints

• Dye sub printing and the cost of paper and toner (ribbon) is often higher than inkjet printing

Size is Everything!

If you need one printer that meets all your needs, you have to ask yourself the question: how large will you need to print? If you regularly (or even occasionally) need to print at a size larger than 8x10, you are basically limited to wide format inkjets as consumer level dye sub printers are limited to 8x10. In the dye sub category, we start out with the small 4x6 versions that normally sell for $200 or less and then we move up to the "big boys" like the Olympus P-440 or the Kodak 8500/8600 series that can print up to 8x10. Beyond 8x10, you will be looking at either a wide carriage inkjet (13 inch wide capable of printing to 13x20 or higher) or a "super wide" 24 inch or 44 inch wide professional inkjet. The latter are mostly used in studios or photo stores that offer digital printing and are beyond the cost of most at-home printing consumers. When selecting your printer, keep size in mind.

Models and options

Dye subs are actually easier to buy because there are fewer models and fewer features to choose from. You simply need to select your maximum print size (basically 4x6 or 8x10) and buy. There are many online resources and online forums available, so search and see what people are saying about the model you picked before you buy. I will refrain from making model suggestions in this article just because I don't want to be inundated with email asking "why didn't you recommend my printer". :-)

Buying an inkjet is a more complicated adventure. If you've decided that a standard 8.5 inch wide inkjet isn't big enough and you'd like to be able to print larger than 8x10, your decision will be somewhat easier because the choices in that size are more limited. If you want a wide (13 inch width) printer, you simply need to decide whether a non-archival printer that uses dye inks is good enough, or you need an archival printer that uses pigment inks. Non archival printers that use dye inks are easier to find and typically produce prints that last 10-25 years when displayed in most indoor lighting conditions behind glass in a frame. Archival printers that use pigment inks typically produce prints that last 75-100 years or longer under the same conditions. If you plan to sell prints, you would be well advised to buy and use an archival/pigment ink printer. Again, the web, online forums, and search tools are your friends. Pick your favorite online "printing" forum and read what others are saying about the printer you have selected. If you are concerned about print longevity, refer to my September article as it refers to some web sites with longevity data for various printers/papers.

One final consideration is whether or not you need to print directly from your digital camera's memory card without using a computer. Many new models offer the ability to print (and even preview and do some basic touchups) right on the printer without even connecting the printer to a computer. All of these printers can still be connected to a computer if you wish for the best quality and editing, but allow you to print in the field or away from home without having to lug your laptop around with you. Whether you print without a computer or not is a personal decision, but in my opinion, I don't recommend using the direct-printing-from-printer method as the quality of your prints is usually not as good as if you print through good quality printing software on your computer, and you have much less control over color, color management, etc.

In Summary:

The bottom line in this article is to be aware of your options, the different technologies available, and be able to assess your needs before you go shopping. Once you understand some of the basics to buying a printer, take your knowledge a step further by applying the general concepts here to the different models that you find online and at your electronics store. In the end, I recommend having your mind made up prior to walking into the local super store because the stores, in general, just don't have the resources to address what is best for you!

Mike Chaney

JPEG Images: Counting your Losses

Standard and "Not so Standard" Formats

Digital photos can be stored in many formats such as JPEG, TIFF, PNG, PSD, PCD and many others. It is important to understand the limitations of each format so that you can select the proper format for the job at hand. This article focuses on the costs and benefits of using the JPEG format, so we won't go into all of the other possible formats in detail, at least not in this article. Of all the dozens of popular formats, some are proprietary and others are considered "international standards". Using a format that is an international standard ensures that you and the people with whom you share images will be able to display them without needing additional software in most cases. Three of the most popular "international standard" formats used on the web are JPEG, TIFF, and GIF. GIF is limited to 256 colors and is used most often to display screen shots and graphs and should not be used for photographs. The remaining formats, JPEG and TIFF, both have their place in digital photography and there are pros and cons to both formats.

Lossy and Lossless Formats

TIFF, often saved with a TIF file extension, is a lossless format. Lossless means that when the image is saved and later reloaded, each pixel in the saved/reloaded image is identical to the image before it was saved. As such, there are no quality losses, but the size of the file can be quite large because the RGB values for each pixel are recorded verbatim. Compressed TIFF's offer a size savings just as WinZip offers size savings for files, without introducing quality loss but even compressed TIFF's are usually larger than JPEG images.

JPEG on the other hand, is a lossy format. Lossy means that compromises are made to allow some image quality to be lost each time the image is saved. In return for the slight quality loss, the file size can be much smaller, on the order of 2-10 times smaller than a compressed TIFF. When an image is saved in the JPEG file format and later reloaded, the saved/reloaded image will not be identical (pixel to pixel) to the original before it was saved. Fortunately, the quality losses can be very difficult if not impossible to detect with the unaided eye after only a single save. Keep in mind that repeatedly opening and resaving JPEG photos will incur cumulative losses with each save, making quality worse each time you resave the JPEG.

Understanding "Compression" and "Quality"

When saving JPEG images, you will normally have a choice of either "quality" or "compression". The higher the compression, the lower the quality because when you compress more (to reduce file size), quality decreases. Just remember that if your photo editor lets you choose "quality" for your JPEG's, higher values will produce bigger files with higher quality. If, on the other hand, your JPEG options include "compression", higher values for "compression" will result in smaller files of lesser quality.

Getting a Handle on Quality Losses

There are two types of losses associated with saving JPEG images. The first type of loss is simply related to the parameters you use when you save the file: set your compression too high or your quality too low, and your images will look worse. The second type of losses are "generational" losses. Generational losses occur when you repeatedly open and resave JPEG files, opening a file, saving it, opening the second copy, saving it to a third file, etc. The greater the number of times you save the JPEG (from a previous copy), the worse your images will look. The first time you save an image to a JPEG, it can be considered a "first generation" JPEG. If you open that first generation JPEG and resave it, the resaved file can be considered second generation since it has gone through the JPEG lossy saving method twice. Remember that losses only occur in the saving process. Repeatedly opening an already saved JPEG without resaving it (modifying it) isn't going to cause losses in quality. Losses are only incurred when you use the "File", "Save" or "Save As" command and you choose "JPEG" as the file type.

Examples of JPEG Quality Loss

Here is an example that demonstrates visible loss of image quality due to saving the same image at different quality settings. The following images were saved using PhotoShop and quality settings between 0 (low quality, small files) and 12 (highest quality, largest file size). As you can see, the lowest quality produces the smallest file size but there are highly visible artifacts in the image such as color blotching, pixelization, and posterization (banding) of colors. As you increase quality, these artifacts start to disappear, but file size increases as an inevitable cost. Note that once you get to about quality 10 or higher, it is nearly impossible to distinguish between the JPEG and the original image (before saving to JPEG) for most images. As a result, as long as you save at a high quality (low compression) setting, JPEG is certainly a valid format for a "first generation" save and can rarely be distinguished from a lossless save such as a TIFF image as long as a high quality setting is used.

Below is an example of "generational losses" from opening and resaving in the JPEG format. Notice that quality is very reasonable for the first few saves but losses become evident beyond about 5 saves depending on the quality setting used. Below, "generation" indicates how many times the JPEG has been resaved based on saving copy 1, opening copy 1 and saving copy 2, opening copy 2 and saving copy 3, etc. Notice how the generational losses are less evident when you save each copy with a higher quality setting. The quality differences are more subtle with generational losses when compared to simply picking the wrong quality level (above), but by the 10'th generation, obvious blotching and color changes are occurring.

What about JPEG 2000?:

There is a newer and less [visibly] lossy version of the JPEG format known as JPEG 2000, often saved with a J2K or JP2 file extension. The JPEG 2000 format has similar issues when compared to the JPEG format but to a lesser degree. In addition, the JPEG 2000 format offers a "lossless" mode in which images can be saved without any quality loss, but with a somewhat larger file size. In general, JPEG 2000 offers higher quality than JPEG when comparing the same saved file size. So why not use JPEG 2000? Many people are, however, JPEG 2000 is not as widely supported and is generally much slower than JPEG. In addition, if you have a camera and you shoot in JPEG mode where your camera delivers a JPEG file on the memory card, there is no benefit to resaving those JPEG images to JPEG 2000 images since that will incur further quality losses over the original JPEG, unless you use the lossless JPEG 2000 mode which will serve to do nothing but increase file size over the original JPEG. In general, JPEG is just easier to use, more portable, faster, and can be readily displayed quickly on the web, in email clients, and other third party applications. With time, JPEG 2000 decoders will get faster, will be more widely available, and more tools will support them, possibly even some future cameras. So far, the JPEG 2000 format really hasn't "taken off" in the industry like was anticipated, but time will tell.

What's the Bottom Line?:

The JPEG image format offers a way to save images using less space, but with some loss in image quality. Typically, a first generation save will be almost as good as a lossless TIFF as long as you use quality levels close to the highest available. Some "die hards" claim that you should never use a camera in JPEG mode when you have TIFF or RAW available as an option, and one cannot argue that you get the best quality and best editing capability with TIFF or RAW when compared to JPEG. That said, JPEG is a perfectly valid format to use even when capturing images the first time in your camera, especially when memory space, shooting speed, or the ability to print images without post processing is important. Remember that JPEG's are processed and ready to view/print, whereas RAW images require post processing to "develop" the images from the raw data. This takes additional time and can complicate your shoot-to-print workflow. A first generation JPEG will offer quality comparable to any other final or ready-to-print format, however, cannot offer latitude for correcting exposure and other shooting issues like a RAW image or a 48 bit TIFF. Bottom line: choose what works for you, but be sure to take the pros/cons of each format into consideration.

Mike Chaney

The Great Paper Chase

Finding the right paper for your printer

In addition to paper made by the manufacturer of your printer, there are many combinations of third party papers available at different price points. How can you be sure which papers offer the best combination of price and quality for your work? You could always use the "buy it and try it" approach, but that can get expensive as you start to collect stacks of paper in the corner that don't work well with your printer. Some papers may not even work properly in your printer; the ink may never dry, the dot gain can make dot patterns too noticeable, and ink pooling may occur. Here are a few tips on buying paper that might help save you some time and money.

Paper types and coatings

All papers start out with a matte surface. The coating applied to the paper is what gives the paper some level of gloss. Different coatings and amounts allow for anything between a matte surface (little or no coating) to luster and semigloss (coarse coating) to premium glossy papers (fine, smooth coating).

While some are better than others, most matte papers work in all printers and with all inks. The quality of the matte paper basically depends on the "weave" of the paper as to how much resolution the paper can handle. In general, matte papers offer reduced contrast and color gamut when compared to glossy papers because the ink doesn't sit on the top of a smooth surface. Due to the ink interacting directly with the paper (instead of the coating), matte papers can be more difficult to profile and usually have less vibrant colors. On the plus side, matte papers tend to be less prone to gas fading (fading of colors due to exposure to gases in the air) and are usually easy to match up with different printers.

All papers with coatings force the inks to interact with the gloss layer, making inks sit closer to the surface of the paper. This is a good thing for contrast and color gamut because the inks don't get "diluted" by the paper surface. Other problems, however, are introduced due to the chemical interaction between coatings and inks. Some types of coatings are compatible with dye inks (most inkjet printers) and others are compatible with pigment inks (archival inkjets). In general, any paper with a coating will have higher dynamic range (contrast), better color gamut than a matte paper and will be easier to profile using profiling software, that is, as long as the paper is working properly in your printer!

Ink type versus paper type

If you have a dye sub printer rather than an inkjet, you will have a very limited selection of papers to choose from, usually those sold by the company who makes your printer. In a way, that's a positive trait because you know what works with your printer and won't get confused with all the options. On the other hand, you'll have fewer options and will have to pay whatever the manufacturer charges for your paper.

If you have an inkjet printer, make sure you know what type of inks you are using. Most inkjets use dye inks unless otherwise specified. Archival printers, printers designed to produce longer lasting prints, use pigment inks. There are fewer pigment ink printers on the market, and as of this writing, most of the pigment ink printers are Epson inkjets. The most common Epson pigment inkjet printers are: R800, 2100/2200, 2000P, 4000, 7600, 9600. Most other consumer model printers use dye inks unless you buy third party pigment inks to replace your original inks.

• Microporous/nanoporous paper: Most high gloss paper is a porous paper designed to accept both dye and pigment inks. These papers generally produce high resolution prints with the least noticeable dot patterns and are water resistant. Porous papers offer the highest print quality and often do better at realizing the resolution potential of your printer, however, they are known to be more prone to gas fading when using dye inks. Porous papers are usually labeled "quick dry" or "instant dry".

• Swellable polymer papers: Swellable papers are designed to greatly reduce gas fading issues with dye ink printers to produce dye ink prints that outlast those printed on porous paper. They do this by encapsulating the ink inside a gelatin like coating that actually swells when it reacts to the ink. These papers, which normally are not recommended for use with pigment inks, produce good quality prints on dye based inkjets that resist fading but they are not water resistant. Prints on swellable papers often produce slightly more noticeable dot patterns, making them look a bit "grainy" to those who are sensitive to dots in prints. Inks also take longer to dry on swellable papers (sometimes days) and even when dry, a single drop of water accidentally rolled down your print can ruin it. Some inkjets also have problems with ink pooling on these papers, particularly the Canons since they print much faster than other printers. The plus side of course, is the simple fact that your dye based prints will not fade as fast as they would on porous papers, especially when the print is exposed to the air (not under glass). Some examples of swellable papers are Ilford Classic Pearl, Ilford Classic Gloss, and Epson Colorlife. Swellable papers are usually marked "not compatible with pigment inks".

Where to start

If you use a pigment (archival) based printer and prefer a glossy or luster surface, I would suggest sticking with the porous papers such as Epson Premium Glossy Photo Paper or Epson Premium Luster paper, both of which can be found in most office supply and computer stores. Ilford and Red River also offer great glossy papers so be sure to check them out as well. If you like high gloss, Epson Premium Glossy paper is a staple in the industry that seems to work well in just about any printer, whether your printer uses dye or pigment inks! Note that if you are using an Epson archival printer with Ultrachrome pigment inks (2100/2200, 4000, 7600, 9600), your prints may exhibit some gloss differential, often referred to as "bronzing", on high gloss papers. This effect can be seen when viewing the print from an angle, as the gloss on the surface of the print may appear more/less glossy in places depending on how much ink is placed on the print. This problem can be minimized by using a luster or semigloss paper or completely eliminated by using matte paper. The R800 is currently the only Epson pigment printer that does not suffer from this gloss differential/bronzing problem on high gloss papers.

If you have a dye based printer and you are concerned about longevity and print fading, you may want to try one of the swellable papers. One favorite on the web seems to be Ilford Classic Pearl. Just be aware that swellable papers can produce more noticeable dot patterns and sometimes ink pooling. Dot patterns can be seen by looking closely at light areas on your prints such as the sky, clouds, or other bright (almost white) areas. Ink pooling can be found by printing an image with a wide variety of colors such as a color chart with many color patches and looking at the print at an angle. If the print appears to have differences in the amount of gloss on the surface, pooling might be an issue. When pooling occurs, it can often be seen in the darker colors on the print where more ink is being deposited on the paper.

Any time you decide to use a third party paper, it is very important to read the notes that come with the paper. There will usually be an insert in the package that tells you which selections to make in the print driver for your printer. Making the proper selections is important because your print driver will only have "standard" selections based on papers from the same manufacturer as your printer. That means that you'll have to select a paper in the driver that is not the paper you are using, but the one that works best with your third party paper. Again, settings for different types of papers are usually listed on an instruction sheet included with the paper.

Acid Free

If you are creating scrapbooks where it is important to use acid free papers, I recommend getting a pH testing pen to test your favorite papers. Acid free is not normally an aspect of paper that is listed on the package, and even when it is, you may not be able to trust the claim because sometimes the front is acid free while the back of the page is not. It is always best to buy an inexpensive pH testing pen and test for yourself. In general, papers that are rated for greater longevity such as those marked "fine art", "archival", or "colorlife" will be better for your scrapbooks anyway, even if they are not acid free. By the way, in case you are wondering, almost all prints that you get developed at your drug store or 1 hour photo that are based on regular film are not acid free.

What about print longevity

Print longevity is something that in my opinion, is still not tested using methods that will give you an idea of how fast your prints will fade in your particular display environment. Nevertheless, there are outfits who do longevity research and can give you a reasonable idea of how your printer/ink/paper stacks up to others with respect to how fast your prints might fade. Here are a couple of links to longevity based testing. You may be able to find your printer, ink, and paper combination to compare longevity with other combos by visiting these sites:

Wilhelm Research

Livick.com

Final Thoughts:

As with anything else, a little research can save you a lot of time. Walking by the photo paper display at an office superstore and picking a paper that has the best packaging, the best wording like "ultra", "professional", "premium", or picking the one that has the best claims on the cover can be an expensive and unrewarding proposition! The best advice I can give is to check out the online forums and do some searches for your type of printer with the word "paper" in the search. Sticking with the paper made by the manufacturer of your printer is always a safe bet, but if you have certain issues that you are trying to address like print longevity or even cost, chances are good that others have been in the same spot and have already found the answer that will work for your printer and your ink. When you make your decision, see if any sample packs are available for the paper you have chosen, or order the minimum number of sheets to try. That way, if you do encounter any of the issues mentioned in this article such as ink pooling, graininess, problems with drying time or water fastness, or other problems, you won't be stuck with a lot of paper you can't use.

Mike Chaney

Options for your printer

There are three basic options for getting the printer profile(s) you need. You can get ready-made profiles on the web but be aware that a printer profile is designed for a specific model, paper type, ink, and print driver settings, so finding the right combination for the printer, paper, and ink that you use can be difficult at times. The second option is to print a test chart, send it off in the mail, and have someone create a profile by using specialized equipment to examine your printed target. These profiles tend to be quite accurate, but you are charged on a per-profile basis so if printer, paper, or ink changes, you'll usually need to pay again to have a new profile made. The final option is to purchase profiling software that can create profiles for you based on your own test prints. To get profiles as good as the custom ones that you send off for can cost $1500 or more if you go with your own profiling software, but much lower cost ($79 to $299) software can do a more than adequate job just using your printer and your flatbed scanner. Let's examine the pros and cons of each option:

 

Options for your printer
Option 1: ready made profiles	Option 2: custom profiles	Option 3: create your own profiles
Often free or low cost	Usually about $40 per profile	Wide range of self-profiling tools ranging from $79 to over $1500
Instant gratification: download and install	Can take several days to a week to print the test chart, send it through the mail, and receive your profile back via email	Nearly instant gratification plus the ability to do some "tweaking" of the profiles on your own. Must get to know the software though and learn how to effectively create your own profiles
If there is a cost, you must pay separately for each profile	Pay separately for each profile in most cases	Pay once for the software and develop as many profiles as you like. If you change to a different kind of paper or ink, just reprofile.
Can sometimes be found on the printer manufacturer's web site under "Tech Support"	You print a test chart and mail it to the outfit doing the custom profiling	You print a test chart, scan it using a scanner or spectrophotometer and use the software to create a profile from the test chart
Device must be set to very specific parameters/options and documentation on the needed settings is often poor or non-existent	Outfit creating the custom profile for you will tell you what options to use on the device before you print the test chart	You decide what options to use when you create the profile and simply use the same options all the time, ensuring that the device always produces the same color output
Due to differences that occur naturally even within the same model line, this method is usually the least accurate, however, acceptable results are possible.	Since most custom profiling outfits have the training and (high end) equipment to do the job, custom profiles tend to be the most accurate available.	Results are often better than option 1, but may be slightly worse than option 2 depending on the equipment used. Less expensive profiling tools use desktop scanners to "read" test charts printed by your printer for example, so your profile quality will be related to the quality of the printer and scanner.

Option 1 for printer profiles

If you decide on option 1 for printer profiles (ready made), here are a few places to look, but again, be aware that quality can vary greatly among choices here:

Before you start, be aware that your printer profile must match the printer, paper, and ink you are using, so don't try to use a profile for a similar (but different) paper or ink set.

• Some printers come with a few "generic" profiles that install when you install the print driver. These can usually be found in your Windows color folder: \windows\system32\spool\drivers\color under Windows XP or \windows\system\color on older versions of Windows. Be wary of these, however, because unless the file name or description inside the profile specify the exact paper and settings to be used, these generic profiles will be of little use and will probably not result in a good color match. They may, however, result in some overall improvement.

• Next, check the manufacturer's web site. Some manufacturers have started making free ICC profiles for certain printers and papers available under their "Tech Support" category. If the site has a search function, try searching for: ICC profiles.

• Some free Canon S900/S9000 profiles can be found here.

• My own web site has printer profiles for $25 for some popular printers and paper, with full documentation on printer settings.

• Inkjetmall has some profiles in the $25 to $40 range, but these can come with hit-or-miss documentation and results.

• Again, the profile you use for your printer must match the printer model, exact paper type, ink being used, and the print driver settings needed for the profile. If any one of these is not known, the profile is basically useless, so save your time even trying them.

Option 2 for printer profiles

There are a number of outfits online that can create printer profiles for you. They can give you an image and instructions, you print that image, and send the resulting print to the company. They will use specialized equipment to examine the print you sent to them and will send you a profile via email, usually in a few days. Two popular outfits that consistently get good reviews are:

http://www.cathysprofiles.com

http://www.drycreekphoto.com

Option 3 for printer profiles

You may decide that being able to develop and tweak as many profiles as you like is the way to go. If so, be aware of a few things:

• Learning to use the software and being able to do minor tweaks can take a few hours or even more, so be prepared for a learning curve and wasting a few pages of paper and some ink while you get acquainted.

• If you decide on the lower cost scanner based profilers, having a good scanner is essential. Many of the lower cost profilers can do a good to excellent job but having a good quality scanner can go a long way. You are basically using your flatbed scanner to scan two targets: the included reference and your printed sample. Scanners also suffer from "metamerism" in that they don't see light the same way your eyes do. As of this writing, one of the best and affordable scanners for the purpose of creating printer profiles is the Canon LiDE 80. The LiDE 80 uses an LED light source that reduces metamerism issues, resulting in a better profile right from the start compared to most other scanners which use a flourescent light source.

• Be patient, read the documentation, and ask for help when needed. Expect to get good results from the start (with good equipment), but the best results come with experience.

• The best equipment and the best experience can produce very good printer profiles from scanner based profiling tools. The best scanner based profiling tools will get you profiles that might be 95% perfect while the high end profilers and equipment (or getting a custom profile in option 2) can get you close to 100%. Whether the price difference is worth it or not is subjective.

Here are a few profiling packages that you can use to create printer profiles. Note that most of these solutions offer the ability to create scanner profiles as well as the ability to do visual monitor calibration.

Profile Prism at $79: camera, scanner, and printer profiling with visual monitor calibration

WiziWYG at $89: scanner and printer profiling with visual monitor calibration

Monaco EZ Color at $299: scanner and printer profiling with visual monitor calibration

Eye-One Photo at about $1500: monitor and printer profiling (high end, spectrophotometer based)

Now we have some profiles. What do we do with them?

OK. Let's assume by now that we've either found, created, or had someone create all the profiles we need. Specifically, we have a profile for each block in the color management diagram:

Software that is fully "ICC aware" will have ways of dealing with the profiles in each box of the above diagram. Setting up color management in the application of your choice usually entails finding the proper menus or windows to enter the above information. High end photo editors such as PhotoShop and high quality photo printing tools such as Qimage are fully ICC aware, but the color management setup is a bit different in each. You should refer to the software documentation/help regarding color management for specifics on how to "hook up" the proper ICC profiles. Below is a short synopsis of two popular color managed applications, PhotoShop and Qimage:

PhotoShop:

• Camera or scanner profile: When you open an image from your camera or scanner, if that image is not tagged with the profile actually embedded in the image file, you may be asked to select the profile when the image is opened. If not, use "Image", "Mode", "Assign Profile" to identify the profile for the image.

• Work space: Click "Edit", "Color Settings", and select the RGB work space: Adobe RGB is usually best. Don't worry about the CMYK, Gray, and Spot selections for now.

• Monitor profile: PhotoShop will use the monitor profile identified on your Windows "Display" properties "Color Management" tab. You can get to your display settings by right clicking on your desktop background and selecting "Properties". To change your monitor profile in PhotoShop, you must exit PhotoShop, change your display settings, and then restart PhotoShop.

• Printer profile: Click "File", "Print with Preview" and select your printer profile under "Print Space". Use "perceptual" rendering intent unless you have trouble with certain colors, in which case you can try "relative colorimetric". Leave "Black Point Compensation" checked. When you click the "Print" button, be sure to click "Properties" for your printer and make sure to set all print driver settings as required for the profile! PhotoShop will not remember your print driver settings from one session to the next so remember this important step each time you enter PhotoShop.

• Note: PhotoShop will only "see" and list profiles stored in the system color folder, normally \windows\system32\spool\drivers\color of \windows\system\color. It may also have trouble if you have two different profiles (with different file names) that have the same internal description. If you don't see the profile you are looking for, make sure the profile is in the proper folder and that it has a unique description, and then restart PhotoShop.

Qimage:

• Camera or scanner profile: Like PhotoShop, Qimage will automatically recognize the proper profile if the profile is embedded in the image file. Unfortunately, for files downloaded straight from a camera or scanner, this will usually not be the case. Qimage allows you to specify profiles to associate with certain types of images. Check out examples 18, 19, and 28 in the Qimage help under "Learn by Example" to see how to associate a particular profile with your camera/scanner.

• Work space: Qimage does not have a separate work space as PhotoShop does. Qimage allows you to edit your images in their original color space, eliminating the need for a separate work space. Simply open or edit your original images and Qimage will follow the blue/dashed lines in the above diagram when displaying/printing.

• Monitor profile: Right click on the text next to "Mntr ICC" on the bottom right of the main window to select your monitor profile. Note that even if you profiled your monitor with a monitor profiling tool, you should still enter the monitor profile under "Mntr ICC". The Windows system does not load your monitor profile at the system level, so specifying the monitor profile here is not double profiling. The change that you see when Windows starts up is an initial "calibration" stage that is needed in addition to the profile; it is not the profile itself being loaded.

• Printer profile: Right click on the text next to "Prtr ICC" on the bottom right of the main window to select your printer profile. Use "perceptual" intent unless you have trouble with certain colors, at which point you can try "relative colorimetric" intent. Leave "Black Point Compensation" checked. Click "File", "Printer Setup" and click "Properties", making sure to set all print driver settings as required for the profile! Qimage remembers all print driver settings from one session to the next but if you regularly use more than one profile, you can click "File", "Save Printer Setup" to save all printer related settings including the driver settings, printer profile, etc. so that loading them in the future will ensure the proper settings for the profile without worrying if you've set everything the same.

Other options for color management:

After reading this article, you may still question whether you really need color management via ICC profiles. Keep in mind that there are a lot of people who simply print what comes out of their scanner or camera without ever understanding color management or using ICC profiles, and they are satisfied with the results. I'm a firm believer in "if it ain't broke, don't fix it" but in this case, it is often difficult to know what you are missing without seeing the results of a color managed system and comparing that with what you are used to. There are a lot of different combinations of cameras, scanners, monitors, and printers out there and some work well together without any color management. It is rare, however, to get a really good and accurate color match among all devices without some form of color management.

What about EXIF Print, Epson's PIM, and PIM II? These options can help resolve overall "complaints" about prints being too dark or bright, oversaturation or undersaturation, etc. but they are not considered full color management because they are generally options that only handle color from certain (supported) cameras to certain (supported) printers. They do not help with monitor color or scanners, nor do they ensure any known level of color accuracy like ICC profiles. In addition, these options tend to be poorly supported in most applications, requiring specialized software or "plugins" to use. If you have the required software (which may have even been supplied free with your printer) and your camera supports either EXIF Print or Epson's PIM, it might be worth trying if you do not want to take the leap into full color management using ICC profiles.

Final Thoughts:

At this point, you've read through a lot of material. I've tried to give you the basics of what you need to know to get your feet wet in color management. Refer to the diagram and try to grasp the concept of having a profile for each box in the diagram. Also remember that your ICC aware software is responsible for getting you from one box to the next, so you don't have to worry about the process; only that each device in the process needs its own profile and that you have software that can handle converting color from one device to the next.

Color management and use of ICC profiles is relatively simple in concept but often very difficult to describe. I hope that this article has given you the basics and will allow you to move forward in the area of color management as you see fit. Color management via use of ICC profiles is the professional's choice for ensuring accurate color and can provide substantial benefits in increased color accuracy when set up properly.

Mike Chaney

Over the gamut and through the woods.

So you want to manage color?

It seems that the longer you stick with a particular hobby or profession, the more complicated things get. In digital photography, once you get past that initial thrill of being able to view, edit, and print your own photos, you start to become aware of subtleties like the fact that certain colors on your monitor don't match what is printed. You do some research and it seems that there is something called "color management" or "ICC profiles" that can fix your problem, but the whole concept seems almost like snake oil, or worse... some foreign language only spoken by rocket scientists. Before long, you find yourself trying a bunch of downloaded files (profiles), messing with rendering intents, turning on/off something called "black point compensation", and instead of a good color match between your monitor, scanner, printer, and other devices, you become lost in a forest, screaming for help just hoping someone will hear you. Is it really possible to understand this "color management" concept to the point where you can at least determine if you need it and if you do, exactly what you need to make it work? Well, we're going to try. We'll try to deal with concepts instead of underlying math where possible so that we don't get caught up in the "rocket science" of it.

Red, green, blue, yellow, magenta, and cyan

Before digging into color management, let's take a look at how different devices represent the colors you see in a photograph. Devices that emit their own light (like monitors and projectors) or collect light using sensors (like cameras and scanners) normally use intensities of red, green, and blue to produce different colors. Devices such as printers that produce output that relies on reflected light normally use a combination of yellow, magenta, and cyan to filter light hitting the paper so that the light reflected off the paper is the correct color.

For the majority of colors, it is possible to reproduce the same color using either RGB (red, green, blue) or CMY (cyan, magenta, yellow) primary colors. While printers ultimately place some combination of CMY inks, dyes, or toner on the paper, the print driver normally accepts data in RGB and the driver uses the RGB data to "convert" to CMY for the final print. The fact that almost all device drivers operate under the RGB scheme allows us to simplify things and work with a single set of primaries. In a typical setup then, your camera, scanner, monitor, and printer all work with RGB values. The RGB values are passed to the monitor for display and RGB values are sent to the printer for a print. There is no need to worry about the fact that your printer doesn't use RGB inks: the driver takes care of that and the print driver still wants the data in RGB form.

In a digital image, we can specify intensities of red, green, and blue for each pixel to identify the color of the pixel. Red and green make yellow. Red and blue make magenta (purple). Red and half intensity green make orange. Etc. Line up all the millions of pixels containing RGB values in rows and columns and you get your final image (the photo).

All colors are not created equal

Since our camera, scanner, monitor, and print driver work and allow us to think in terms of RGB, we are tempted to think that sending the same RGB values between devices will result in the same color. As a result of cameras, scanners, monitors, and printers all using different technology to reproduce colors, however, they each use a slightly different shade of red, green, and blue as their primaries. The devices may also have slightly different "tone curves" so that a particular change in RGB value won't produce the same change in visible light from both devices. These issues mean that mixing the RGB values at the same brightness level on each device will produce a similar color, but not an identical color since we are starting with RGB primaries that don't exactly match and may also have non linear response with respect to brightness. The reason for the "mismatch" in RGB primaries can get complicated, but we need not understand why the differences exist, only that they do.

ICC Profiles: the language of color

At this point, it is becoming clear that we need a way to convert the color from one device to another, i.e. one set of RGB values to another. Our camera recorded red, green, and blue intensities of 200, 200, 45. What intensities do we need for our monitor to reproduce the same color? We know it most likely isn't going to be 200, 200, 45 like the camera. Is it 202, 189, 56? Is it 192, 205, 38?

We could probably get the conversion pretty close with many hours of trial and error testing just eyeballing results and we could write software that carried out our observations to do the conversion. The problem is, our software would only be good for that one specific camera model and that one specific monitor because each camera and monitor will work differently. What we need is a language that describes the primary colors themselves and a color management "engine" that can look at the language spoken by the two devices and translate from one to the other. We could then specify the "color space" for a device which is determined by the primary colors used by the device, and ask our color management engine to translate between the camera's color and the monitor's color for example.

ICC profiles are specifications that describe the language of color spoken by a particular device. An ICC profile for your camera describes the subtleties of how your camera speaks RGB. Similarly, an ICC profile for your monitor describes the subtleties of how your monitor reproduces RGB colors on the screen. Once you know the language of the camera and the language of the monitor, the color management engine can translate from the camera's language to the monitor's language to get accurate color on the monitor. If you know the subtleties of the language spoken by the printer, you can do a similar conversion from the camera's RGB language to the printer's RGB language to reproduce accurate color on the printer as well. The color management engine acts as the "universal translator", translating the color of one device to the next. All you need are ICC profiles that describes the "dialect" of the RGB language spoken by each device; a profile for your camera (either a generic profile or one for a particular light source), a separate profile for your monitor, one for the printer, etc. The profiles themselves describe the color of the device in a "universal dialect" called the Profile Connection Space (PCS) which the color management engine can use to translate color from one profile to another, but with that, we're getting a little more technical than we need.

The above chart shows our input devices (camera and scanner) on the left, our photo editing tools where we modify our images in the middle, and our output devices (monitor and printer) on the right. We need a profile that describes the color space for each of the five areas above. In the context of this article, we can use "color space", "ICC profile", and "profile" synonymously. The path is usually from left to right, starting with the original image, converting to some common work space to modify the image, and then converting to the monitor or printer color space when we are ready for output.

When going from one area to the next, our color managed software simply converts from the color space in the box where we came from to the one where we are going. As long as our color managed software knows the color space (profile) for each box, it can get you from one box to the next with consistent color. Note that the actual RGB values for the image in each box are slightly different, but the image looks the same because the proper mapping has been done from one set of RGB values to the next. Also note that if we choose not to edit our images and simply want to display or print the originals, we can follow the dashed blue lines where our color managed software can convert directly from the camera or scanner profile to the monitor or printer profile. Having a common work space (Adobe RGB being the most popular) in the center box is not a requirement as it is possible to edit images in their "native" color space on the left, but Adobe RGB (or sRGB) is often used for consistency. The emphasis here is that we need a profile for all boxes in the above diagram. If we have a profile for every box except the printer, we cannot produce color managed output for the printer because while we may know the color language spoken in all the other boxes, not knowing how the printer speaks RGB means that there is no way to convert to the printer's language.

ICC Profiles: a visual representation

We have learned that in addition to devices having unique RGB primaries, there are standardized "work spaces" that have their own (carefully picked) RGB primaries as well. These work spaces are basically ICC profiles designed to allow editing of images in a known "color space". A color space is the area mapped out by drawing a triangle between the red, green, and blue primaries as shown below.

The above is an abstract representation of two of the most popular work spaces: sRGB and Adobe RGB. The entire/outer colored area is an approximation of the colors visible to the human eye, called the "gamut" of the human eye. The triangles map out the color spaces or the gamut of colors spanned by the sRGB and Adobe RGB color spaces. As you can see, using different red, green, and blue primaries allows you to cover a larger or smaller portion of the visible gamut. Why not just pick primaries that allow you to cover the entire gamut? Again, the answer can get complicated, but it is partially due to the fact that it simply isn't possible given the technical capabilities of certain devices (like monitors, printers, cameras, and scanners) and it isn't always practical in a mathematical sense either.

It is obvious by looking at the above that sRGB covers a smaller gamut than Adobe RGB. sRGB covers a gamut similar (but not identical) to your monitor so it is well suited for display of images. Adobe RGB on the other hand, covers a larger gamut and is better suited for images being reproduced on a number of different devices that might be capable of producing colors beyond the sRGB gamut (many printers can produce cyan and yellow colors beyond the sRGB gamut for example). Most consumer level point-and-shoot cameras record images in a color space close to sRGB above, even if that is not specified in the manual or documentation for the camera. If you have a selection for color space on your digital camera or raw conversion software and you choose Adobe RGB color space, your camera will be able to record colors beyond those in the typical sRGB gamut, particularly in the area of saturated cyan and green.

Being able to select color spaces like sRGB or Adobe RGB in your camera gives you an added benefit: you'll automatically have a profile for your camera (the profile for sRGB or Adobe RGB is included with most color managed software). If you are using a point-and-shoot camera and no mention is made of a profile or color space, you'll have to assume sRGB unless you decide to get or create a profile of your own (see below).

Now that we know what a profile is, where do we get them?

We know that a profile can describe the subtle color response of a device, and that we need a profile for each device to be able to manage color between devices (in order to render the same or visually-same colors on each device). Now all we need is a profile for our monitor, one for the scanner, one for the camera, and one for our printer/paper/ink combination. Profiles are just files that go in your Windows color folder which is usually \windows\system32\spool\drivers\color or \windows\system\color. The files you are looking for will have either an ICM or ICC extension such as my_printer_profile.icm or my_monitor_profile.icm. Sounds easy but this can often be the stumbling block in a color managed workflow. Let's take a look at the options:

Options for your camera

Most of the latest dSLR cameras (the high end pro and prosumer models) come with a user selectable color space. Remember that "Color space" in this context is synonymous with "ICC profile". Most have sRGB and Adobe RGB to choose from and if you are working with software that can handle profiles, Adobe RGB is generally the best choice to select in the camera setup menu. Setting the camera to Adobe RGB will ensure that images from the camera conform to the Adobe RGB profile. If you usually just download pictures from the camera and put them on the web or send them in emails without modifying them, sRGB may be the better choice because the sRGB color space (profile) is closer to your monitor's profile than Adobe RGB. One common mistake is to select Adobe RGB in the camera (or raw conversion software) and then send the image to someone via email. When the recipient views the email, he/she will see the wrong colors because Adobe RGB is not well suited for viewing on a monitor (the color space "triangles" don't closely match). The solution is to convert those Adobe RGB images to sRGB using your color managed "ICC aware" software before sending them in an email.

In contrast to high end cameras that allow you to specify a color space, if you have a consumer "point and shoot" camera, there may be no selection for color space and generally no indication of what should be used for a profile. In this case, it is usually best to just use sRGB as the "assumed" camera profile. There are some camera profiles available online such as those on the Popular Photography site, but in general, it is very difficult to create profiles for JPEG and TIFF images from a camera because cameras often respond differently under different lighting and it can be difficult to recreate the exact settings used/needed on the camera for the profile to be accurate. If you shoot in raw mode and develop your photos with a raw conversion tool, it is the responsibility of the raw conversion tool to convert your raw images to JPEG's or TIFF's under a user specified color space. In other words, you should not need to look for a profile if you convert raw files with a raw conversion tool because the raw conversion tool should have output options like the ability to save converted images in either sRGB or Adobe RGB color spaces.

It is possible to create a profile (or profiles) for your camera using a profiling tool such as those mentioned in the scanner and printer sections below, but developing profiles for cameras is generally not for the novice and requires very exacting framing and lighting.

Options for your scanner

Scanners are actually quite easy to profile using profiling software, but you may be able to find a generic profile online (or your scanner may have come with some) that are accurate enough. Even the low cost profiling tools do a good job with scanners. Just scan an included color chart, mark the four corners of the chart in the software, and the profiling software will create a profile for you. Some popular low cost scanner profiling software are: Profile Prism by my company (Digital Domain Inc.) at $79, WiziWYG from Praxisoft at $89, and Monaco EZ Color from Monaco Systems at $299. There are even some free options online such as IPhotoMinus but the free tools are limited to scanner profiling only, do not come with the necessary color target to scan (which you'll have to locate and buy), and generate simpler "matrix shaper" profiles that are not as accurate as the tools listed above.

Options for your monitor

About the only reliable and accurate method of obtaining a profile for your monitor is to buy monitor profiling software that comes with a device called a "colorimeter" that attaches to the screen to take actual measurements and create the profile based on measurements. You can sometimes find a generic profile for your monitor on the monitor manufacturer's web site but these are usually quite poor because monitors really do change significantly with age, requiring them to be reprofiled once a month or so for accurate color. Two popular monitor profilers are the Spyder by Colorvision and MonacoOPTIX by Monaco Systems. Expect to pay in the $200 to $300 range but with significant improvement in color accuracy on screen.

The visual "calibration" tools such as Adobe Gamma that comes with PhotoShop and other similar tools can help with certain aspects of on screen color, but don't expect a reliable or accurate match using these devices because they are designed for general calibration, not profiling.

The megapixel race. Where did it start? Where will it end?

The race is on

In 1996, I bought my first digital camera, a Kodak DC40. At the time, it was one of the only consumer cameras available and at 768 x 504 resolution, it offered only a little more than one third of a megapixel. It didn't even offer a way to view your pictures on the camera, but it sure was cool. A year and a half later, I shelled out even more cash for one of the next generation: an Olympus D600L with a whopping megapixel of resolution. With that purchase, I became aware that the megapixel race had begun and that I'd be spending a lot of money on this new technology.

The good, the bad, and the ugly

A lot has happened since 1996. Manufacturers have added roughly a megapixel per year to keep us drooling and upgrading as the balance of power begins to show a strong shift from film to digital. As with many advances in technology, it is good to step back from time to time to take a look at where we've been and where we are going. How many megapixels do you really need? Is anything lost along the way or are the latest 8 MP cameras really 8 times better than the 1 MP versions from years ago?

To answer these questions, we first need a little background. Since digital cameras became widely available in the late 1990's, the "consumer" camera, the small point-and-shoot style cameras marketed at the masses, have all had image sensors ranging in size from about 6 to 9 millimeters across, roughly 1/4 the size of a postage stamp. While the size of the sensor has not changed, manufacturers keep finding ways to cram more pixels into the same 1/4 postage stamp space.

This may sound great at first, but as with most good things, there is a price to be paid, and that price is image noise (grain). An image sensor contains millions of photo sites, each of which is capable of collecting a charge as light hits the cell. Unfortunately, there is "overhead" involved since you must have some circuitry to store, amplify, and shift the charge over to digital data (the final image). As you decrease the ratio between the size of the light detecting part of the cell and the size or complexity of the electronics, noise increases. This noise can often be seen as grain in images and will look a bit like multi-colored "snow" from an old TV or even larger blotches of color depending on the filtering used.

Megapixels, taming the herd

An image sensor is a bit like a radio antenna. The bigger the sensor, the more light it can collect and therefore the less noise it will have. In contrast to consumer cameras, most digital SLR's have sensors 8 times larger (or more), allowing them to capture more accurate detail and also allowing them to operate effectively at higher speeds (ISO equivalents). Digital SLR's are also designed with much larger sensors in mind and they use larger, higher quality lenses so it is fair to say that the SLR camera in general is more "ready to accept" digital technology. On the other hand, consumer cameras can be more of a challenge when trying to increase resolution while holding the size of the sensor constant. Most consumer cameras were designed around the 6-9 millimeter sensor so increasing the size of the sensor is not cost effective because it will require that the camera bodies (and possibly the lenses) be redesigned. By increasing pixel count and keeping the sensor size constant, manufacturers can use last year's camera body, maybe add a feature or two, round off a few edges, change a few buttons, add a pin stripe, and sell the same thing they sold last year, but with more pixels.

Most consumer cameras in the last few years have used what manufacturers like to call a "1/1.8 inch" sensor which amounts to a sensor about 7.2 x 5.3 millimeters. Obviously the advertised "1/1.8" nomenclature is no indication of the actual sensor size. The 1/1.8 architecture was generally used for consumer cameras in the 2-4 megapixel range. Once manufacturers hit 4 MP, noise was on the increase and compromises were being made. At 5 MP, some manufacturers began switching to what they call a "2/3 inch" sensor (8.8 x 6.6 millimeters), while the rest made the jump to the larger sensor when they went from the 5 to 8 MP mark. Looking at the sensor size alone, the increase may not look like a lot, but the slightly larger sensor amounts to a 1.5 times increase in overall size, giving manufacturers some breathing room to keep moving forward in the megapixel race and alleviating many complaints about noise.

Putting it all into perspective

So what does all this mean to people who are shopping for a digital camera? It simply means that you need to consider more than the pixel count when shopping for a camera that meets your needs. Don't buy into the "8 is better than 5" marketing strategy without considering other aspects of image quality:

• Your needs: What you need to do with the camera is usually more important than the latest jump in resolution. Do you need a point and shoot camera that is simple and will fit into your pocket? Do you need an SLR with manual controls? How much telephoto work do you plan to do and might you need interchangeable lenses? Does the camera offer features that you would find beneficial such as a direct print option or a camera dock to print quick shots on site? How fast is the camera from shot to shot? Most of these questions can be answered with a little reflection on your part and by reading through online camera reviews. When you've narrowed the search to a few cameras that meet your needs, review some online samples at the end of the reviews from your various potential camera selections and compare similar shots to see which you like best.

• Print size: How big do you need to print? If you plan to print 4x6 or smaller prints most of the time with an occasional 8x10, your camera choices will be much broader because it doesn't take as much resolution to print small sizes. Many people argue that 300 DPI (dots per inch) are needed for true photo quality and you may have seen a reference to 300 DPI, but there really is no overall magic number. Prints will generally still look like photos and won't suffer from noticeable pixelization (jaggies) down to about 150 DPI if you print with high quality printing software. Below about 150 DPI, prints start to show jaggies (stair steps in diagonal lines that should be smooth) or they will start to lose some sharpness. Use the following as a rough guideline to how many megapixels you really need:

For a 300 DPI print (super sharp photo intended for viewing up close)
Print Size	Resolution needed for 300 DPI print
4x6	about 2 MP
5x7	about 3 MP
8x10	about 6 MP
11x14	about 14 MP
13x20	about 23 MP

For a 150 DPI print (photo quality when viewed at "arms length")
Print Size	Resolution needed for 150 DPI print
4x6	about 0.5 MP
5x7	about 1 MP
8x10	about 2 MP
11x14	about 3.4 MP
13x20	about 6 MP

When using the tables above, note that it is important to realize that most larger prints are not scrutinized up close or with a magnifying glass and are meant to be viewed from a distance. You can often "get away with" much lower resolution when printing larger sizes simply because people will not usually notice that a 150 DPI print is slightly softer than a 300 DPI print unless they study it very closely. Also note that the idea that you can get away with resolutions as low as 150 DPI depends on the printing tool that you use and assumes that the tool (or you) upsample (interpolate) the print to avoid noticeable jaggies.

• Cropping: How often do you find the need to crop a section of the photo for printing? Does your technique or workflow often require that you crop the photo to get rid of unwanted portions of the image? If so, you need to take that into consideration when using the tables above since cropping an image reduces the resolution of the final print. Framing your photos better when you take the shot can reduce the resolution needed for the job because it means you won't have to waste pixels on things you don't need in the photo.
• Artifacts: What are you (or your intended "audience") sensitive to? Do you like super sharp photos? Do you notice noise (grain) in backgrounds like blue skies or shadows? Some of the latest 8 MP cameras have issues with chromatic aberrations (purple fringing around sharp edges or edges of high contrast). Do you notice this or see it as a problem when reviewing online samples? Does the camera render color that looks good to you? A lot of the buzz on the web regarding "my camera is better than yours" is subjective and the arguments for/against certain cameras will never be settled because different people look for different things in photos. Some focus on detail or resolution while others focus on accurate color, other artifacts in the images, and (lest we forget) some people actually focus on the photograph itself, the content, the framing, etc.
• User opinions: Be sure to check online forums and other online resources to see what people are saying about certain cameras. You may look through samples and decide you like photos from a certain camera better than others only to find out later that you are not able to achieve the same quality as the reviewer who shot the samples. A quick check in a few forums might show a lot of complaints from people really having to "tweak" photos to get good (usually color) quality, so make sure that the quality you see is attainable with your experience and time.
• Photography: This probably shouldn't be the last topic because it is so important. The quality of your pictures ultimately depends on your ability as a photographer and your ability to utilize your tools. I've seen amazing photos from 1.5 to 2 MP cameras that beat photos from 6 MP cameras just because the photographer took the time to learn the tools of his/her trade (the camera itself and any after-the-fact editing tools) and was simply able to take good photos. Let us not forget that the "8 MP" logo on your camera can't make you a better photographer, nor can it make the camera any easier for you to use. Learning techniques and tools from listening to others can be the best way to improve your photographs. A lot of people spend a lot of money each year just to have the latest technology. That can be a disappointing and not very rewarding process if you are lured into thinking that a newer camera will make you take better photographs. The latest technology can help, but often it is more a question of whether you know how to use it and/or whether or not the camera suits your needs.

- Mike Chaney

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Mike

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