Mike Chaney's Tech Corner

Am I to understand that Qimage somehow upresies (ups the resolution) if it is too low for an image. If say I have a 10x8 at 200 res, which is about as low as I like to go, and want to print it 20x16. Will Qimage produce a reasonable print at the larger size or must I run it through Genuine Fractals or OnOne's Perfect Resize to get a file big enough to make a decent print. I know that Qimage sorts out resolution so that you don't have to worry about it (and I never have) but will it do what I am asking effortlessly?
Jules

Hi Jules,
Yes, that is correct. In fact it is one of the main features of Qimage and part of the reason it produces great prints, even from low resolution images. QU also down-sizes for small prints
Linked with the re-sizing that Qimage does is its superior re-sizing algorithms.
So in answer to:
Definitely no! Muliple resizing will degrade an image.
QU re-sizes to the "native" resolution of the printer, eg. 720ppi for Epson, 600ppi for Canon. This avoids the driver "messing up" the pixels.
You can see the reported printer resolution from Qimage above the page preview - the numbers in brackets.
Yes, just select the print size required in QU & put your original image into the queue and print.
I hope that is clear, if not please come back.
The web site has a lot of info'
http://www.ddisoftware.com/qimage-u/quality.htm
http://www.ddisoftware.com/qimage-u/technology.htm
Terry

That's brilliant Terry and the answer I wanted. I thought that Qimage did this but wanted to make sure. I have a very tight crop from a D800 which produces a massive amount of pixels (35Mb) and would you believe that the crop I have out of the middle of the image plus the size I need (10" x 18) that I am a bit short of definition at a res of 180. So hopefuly I should be ok. I have tried a test print and it looked a little grainy (or should I say noisy). But a little sofftening in PS and I think I will strike it about right coupled with Q's upresing and sharpening.

You could do this in QU using Tone Targeted Sharpening: select the tone that needs softening and use a negative percent value to soften; TTS can be set to sharpen the remainder if required. There are several other options and tricks too - I do all my sharpening in QU.  ;)
Just to satisfy myself, I printed a crop of an image to get 180ppi, see attached a screen shot of the page editor with full size and crop of the sample image.
I thought that at normal viewing distance, the 180ppi print was very good. I'm sure you'll get a good result too. Make sure you have "Fusion" set as the interpolation method.
Terry

Hi guys, sorry for a bit of a highjack...
But does anyone know how the resolution dropdown works? I've been experimenting with the different interpolation methods as someone has just given me a really low quality image that need scaling up, fusion does a really good job considering how low the quality is but obviously a bit gloopy looking as it's starting from 55ppi! Anyway, the resolution dropdown gives me the options of 360, 180, 120 and 90. If I set this at say 90 will it resize to 90ppi and then do a pixel resize x4 to bring it up to the native for the printer? 55ppi straight to 360 is a bit ridiculous really!

Thanks

Jamie

Ok, so I've talked them out of using that image. They're looking for another one instead but it would still be good to know...

No, it will re-size to 90ppi to send to the printer.
Looks like you are using an Epson printer, you should be able to get 720ppi with "finest detail" set
Best quality is achieved with the highest resolution the printer offers.
55ppi is rather low!  :o
Terry

Thanks Terry,

55ppi is ridiculously low in fact, no need to be polite. When testing the different interpolation methods via 'print to file' I found that with a really low quality image, using fusion there are so many invented pixels that it just becomes too smooth, there are some others that look similar to pixel resize (can't remember exactly) that are obviously too blocky, but somewhere inbetween would probably look the best. So knowing it'll send it to the printer at 90 or 120 or whatever will be an experiment worth trying. Thanks for mentioning the 'finest detail' button, I'd forgotten that was what gets me 720ppi.

cheers

Jamie

But if you send it to the printer at 120, the printer driver will then interpolate it up to 360 or 720 anyway, and probably not do as good a job as Qimage would have. So picking the interpolation method in Qimage that seems to work best with low res images would probably give best results.

Jeff Jessee

You're right Jeff, figured that out after I did a couple of test strips. To my eye they all looked identical so... Using different interpolation methods are the way to go, though I don't plan on trying to print anything that bad again, but still good to know.

Thanks again.

Jamie