Profile Assessment

CHROMiX ColorThink
1

Does any of the Chromix products provide profile quality assessment tools? I use Chromix Color Think to do gamut comparisons of profiles created off Profile Maker and Print Open. It would certainly be great to have some tool in Chromix to test the quality of the ICC profiles.

Thanks
Vinod Panangat

2

This is an interesting question, because it raises the issue as to what the quality criteria should be. There is certainly more to the ‘quality’ of a profile than gamut volume, for example. The criteria probably vary according to whether we’re talking about a printer profile, monitor profile, scanner profile or camera profile as well. They also vary from one person to another e.g. portrait photographer versus landscape.

How about coming up with a list of criteria that we might want ColorThink to test for us?

For printer profiles, how about these, in no particular order:

(a) greyscale neutrality;
(b) shadow detail;
(c) smooth rendition of gradients;
(d) total gamut volume (in some suitable units);
(e) maximum saturation for the primaries;
(f) colour accuracy for a selected palette of colours.

In terms of ColorThink, (d) and (e) could presumably be measured in situ without using any reference data.

(a) and (f) could perhaps be done by soft proofing a test file, for example the target used to create the printer profile (tagged for this purpose with a suitable colour space profile of course).

(b) could maybe be derived from (f) by using a file containing a large number of ‘dark’ patches.

(c) is a bit harder to figure out. In Photoshop you can just soft proof a file containing gradients & check visually. I’m not sure how ColorThink could calculate ‘smoothness’; maybe Steve knows a way to do this.

Regards,

Alan Rew

3

Thanks Alan.

That was a really great explaination on profile assessment. Another point that would be important to test would be:

  1. The accuracy of the profile in the forward and the reverse transformation directions (B2A and A2B). Color Pursuit(Alwan Color) does this right now and gives a value for the profile quality. May be Chromix will have this feature in addition to the features Alan highlighed on this previous post.

It would be definitely great to hear Steve’s thoughts on this.

Thanks Again.

4

At 1:10 PM -0700 7/22/05, vinod wrote:

Thanks Alan.

That was a really great explaination on profile assessment. Another point that would be important to test would be:

  1. The accuracy of the profile in the forward and the reverse transformation directions (B2A and A2B). Color Pursuit(Alwan Color) does this right now and gives a value for the profile quality. May be Chromix will have this feature in addition to the features Alan highlighed on this previous post.

yea, this type of test (a number of them actually) will be available in ColorThink Pro. Deciding on a “quality number” is not easy so for now I will leave it as reporting delta-E values.

It would be definitely great to hear Steve’s thoughts on this.

there is certainly work to be done in this area (and we’re doing it). See what Pro has to offer (soon) and then we can certainly discuss it more…

Regards,

Steve

o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX

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5

Thanks Steve

Looking forward to the Color Think Pro :slight_smile:. The Color cast technology is really interesting. Great to know that it would allow me to apply multicolor/GOP profiles in Photoshop, that’s awesome.

Great Job, Steve

Regards
Vinod