Mike Chaney's Tech Corner

If I print a 16 bit Tiff file in Qimage with the Epson 7900, which has a 16 bit print driver, will I retain the 16 bits through out the process? If so, should I consider using Pro Photo RGB instead of Adobe RGB?
I don't have the 7900 now but will be receiving it next week. Up to this point I have always worked in Adobe RGB 8 bit from raw conversion to printing.

Thanks,
Andy

No, Qimage is an 8 bit application and will convert a 16 bit image to 8 bits.
You had better read Mike's September 2009 article on the subject:
http://ddisoftware.com/tech/articles/september-2009-digital-photography-reality-check-308
See the third section "Printers, ink, and 16 bit printing"
That's covered too in the same article.
Terry.

Thanks. I remember reading that article and was wondering if anything has changed, because I will be getting my first printer with a 16 bit driver.  I read one review of the printer and the reviewer was saying there was a noticeable difference in quality with some images if they were converted and kept as 16 bit images and then printed on the 7900. I can't remember what review stated this.

Andy

Hi Andy
You be able to see for yourself soon  ;D
Let us know all about it.
Terry.

I don't think you gain much--if anything--from the 16-bit driver.  Inks have a finite range that is much less than the eye can see.  Right now I think it is a sales pitch.

That said, I have been using ProPhoto for a long time but am slowly switching back.  ProPhoto with its larger gamut uses a 1.8 gamma where most others use 2.2 so you wind up making more adjustments in contrast, etc. to compensate for it.

Currently, many Canon cameras have a 14bit raw image, and the colour space is larger than srgb or argb in most cases. This allows you to alter 'exposure', etc., in editing your raw files. Depending on what you want to do with your images, I see little point in throwing away 6 bits of information right from the start by working in an 8 bit colour space. Prophoto has a wide gamut colour space, beyond what your eye, monitor or printer can display, and it can lead to unexpected results in the final image, but being 16 bit, it generally allows more manipulation in smooth toned area, without the visible banding that can occur if working on 8 bit images, usually most noticeable in sky and skin tones.  However, every time you change to a different colour space in your work-flow you will lose information, and you can't recover that by changing back, in fact it will lose you more. So, I think the best solution is to work in 16 bit, and if your printer has a 16 bit driver, then use that. It may be that at the moment the actual print head can not lay down 16 bits worth of different shades, and it may be that you can't see the difference between the result and if you print in 8 bit, but in a few years time the hardware will be capable (but probably your eyesight will be worse  :( ) and it will be you that will be making the choices, not relying on a general purpose conversion algorithm.

You can, of course, avoid these decisions if you shoot in jpeg, or stick with 8 bits throughout - but it depends on the purpose of your images, time, storage space, etc.  if that is a good solution for you.

I can remember the excitement caused by vga colour monitors, in a world of green or amber, (and before that when computers never had a vdu, fwiw). It is a pity, that basically a simple problem is needlessly complicated, but that's the result of too many vested interests I guess  ::) .

Best wishes,

Ray

Mike, is there any chance you will change your mind and allow true 16 bit printing with Qimage?  I am currently looking at Canon, HP and Epson wide format printers and 16 bit is an important feature in my evaluation.  I read your treatise on 8 bit versus 16 bit and am not fully convinced.  It used to be said 8/16 made no difference in PS, but I think that has been laid to rest.  I know I have more latitude when working up a 16 bit file.  Hope to hear that someday you will make this available.  Thanks.
Paul