Luminous Landscape Forum

Raw & Post Processing, Printing => Colour Management => Topic started by: walter.sk on January 26, 2009, 11:19:01 am

Title: How best to avoid out-of gamut colors?
Post by: walter.sk on January 26, 2009, 11:19:01 am
Much of my work involves making a photographic image of something, and then producing an abstract using the following process:  I make a grayscale image and reduce it to either pure black and white using the threshold adjustment layer, or posterize it into 3, 4 or 5 levels of gray.  I then select each of the tones and fill it with a different gradient, usually of bright colors, often primaries and/or complemetary colors. I save these as tiff's, and then convert them into sRGB Jpegs for digital projection.  They come out fine when projected

My problem comes when I want to print the tiffs. The original abstracts are 16bit Prophoto RGB, and almost everything is out of gamut for printing (usually on HP Premium ID Satin, or Epson Premium Glossy, profiled on my HPZ3100).

When I softproof using the paper profile, it seems as if everything is either too saturated, too bright, too dark or just not colors within the paper/ink gamut.  It can take me hours of fiddling to get most of the colors back in gamut, and the results are pretty far from the originals, which look fine on the screen or when projected.

Is there any way to set up my multiplicity of gradients so that they will still look very bright and saturated yet be within the gamut of my paper profiles?

I'm pretty sure that people who do digital illustration have solved this problem, but for me it seems as if I've been trying to reinvent the wheel (color wheel, that is  )

Here is an example:
[attachment=11135:KimmelW_...orRings2.jpg]
Sorry for the double insertion.  I couldn't figure out how to delete one of them.
Title: How best to avoid out-of gamut colors?
Post by: Tim Lookingbill on January 26, 2009, 05:29:15 pm
You might try converting and editing in a much tamer color space that fits closer to printer gamut while providing the stability and neutrality of a matrix profile.

http://photogamut.org/E_ICC_profile.html (http://photogamut.org/E_ICC_profile.html)

It's the best of both LUT based (scanner/printers) and matrix based (sRGB/AdobeRGB working space) profiles for editing such saturated colors. This profile space tends to allow alternative/desirable choices of hue/saturation and smoother transitioning of color over Soft Proofing using the printer profile which can be unstable and limited.
Title: How best to avoid out-of gamut colors?
Post by: walter.sk on January 26, 2009, 09:32:32 pm
Quote from: tlooknbill
You might try converting and editing in a much tamer color space that fits closer to printer gamut while providing the stability and neutrality of a matrix profile.

http://photogamut.org/E_ICC_profile.html (http://photogamut.org/E_ICC_profile.html)

It's the best of both LUT based (scanner/printers) and matrix based (sRGB/AdobeRGB working space) profiles for editing such saturated colors. This profile space tends to allow alternative/desirable choices of hue/saturation and smoother transitioning of color over Soft Proofing using the printer profile which can be unstable and limited.
Looks interesting!  Tomorrow when I'm more awake I'll download it and try it out.  Thanks.
Title: How best to avoid out-of gamut colors?
Post by: walter.sk on January 27, 2009, 10:19:02 am
Quote from: tlooknbill
You might try converting and editing in a much tamer color space that fits closer to printer gamut while providing the stability and neutrality of a matrix profile.

http://photogamut.org/E_ICC_profile.html (http://photogamut.org/E_ICC_profile.html)

It's the best of both LUT based (scanner/printers) and matrix based (sRGB/AdobeRGB working space) profiles for editing such saturated colors. This profile space tends to allow alternative/desirable choices of hue/saturation and smoother transitioning of color over Soft Proofing using the printer profile which can be unstable and limited.
Well, I read the material on the PhotoGamut website again, and downloaded the ICC profile.  I'm not clear on how to use it.  I'll outline what I think the workflow would be.  Please correct me where I go wrong.

1) I set up the Photoshop default working space using PhotoGamut rather than ProphotoRGB.

2) I convert my raw files to the PhotoGamut working space.

3) I do my editing and gradient color selections the same as before, but in the Photogamut space.

4) I softproof as usual using my paper/ink profile as generated with my Z3100's spectro.

I have a feeling that at least (4) is incorrect, and maybe some of the others.

Also, what do I do with images I've already made, such as the one attached at the beginning of this thread?  Do I convert them to the PhotoGamut working space?

Is there an upside or downside to using the PhotoGamut space rather than ProphotoRGB for those images where there are no apparent out-of-gamut problems?

Thanks again for the link.  This really looks interesting, and I have forwarded it to a friend who is interested in improving the color management setup we have been using.