CHROMiX

sRgb v4

I’m moving to the forum a support request.

2 issues in grapher.

Get the sRGB v4 from icc web site.

  1. You can’t display the gamut

  2. You can’t use use to display the rendering of an image in vector display mode.

Note: Same problem with romm rgb from icc. (a generic space v4 too).

Steps to reproduce:

  1. dispaly the sRGB v4 in 3d grapher, you get the error: ‘Unable to plot this file’

  2. Open the grapher
    Load an image
    plot as vectors
    Add a rendering with srgb v4
    You get bad vectors (outside from the gamut of the image)


Answer from Pat

Hi Nicholas,

Thanks for giving us this feedback on ColorThink.

I’m looking over your issue and I’d like to get more information from you, if I could.

Are you referring to the ICC profile sRGB_v4_ICC_preference.icc?
This profile is actually not a display profile like the original sRGB profile, but it is a “Color Space Conversion” proflle. This is a very rare form of ICC profile, and we are mystified by why the website advertises it as a replacement for sRGB. While the website no longer lists this profile as a beta, the internal name within the profile still lists it as a beta profile. The bottom line is that this is not a normal display profile and so cannot be displayed in the Grapher as a normal display profile. However, it does act in ColorThink the way a normal Color Space Conversion profile acts.

colorwiki.com/wiki/ColorNews … e_Profiles

Thanks, and I hope to hear from you on the ColorForums soon, too!

Pat Herold
Tech Support
206.985-6837 ext #6
866.247.6649

Pat,

Thanks for your answer.

Yes the profile I talked about was sRgb_v4_icc_preference.icc which get a problem in Chromix. The other one on color.org (ending with _preference_display.icc) works fine.

As I got the same problem with the romm profile (color.org/chardata/rgb/rommrgb.xalter), I suspected a problem in Chromix.

From the test I’ve done, when you render a proPhoto image into sRgb, only the relative color. method is used. From what I understand it seems to be a limitation of ICC v2.

Rendering into this sRgb v4 (the one ending with _preference_display) makes the perception mode to work in Chromix, as well as in Photoshop. This is the reason why I’m trying to use this profile, but I don’t know if there are other site effects ?

The gamut of the sRgbv4 (_pref_display) is a little bit different than the gamut of the sRgb v2 I have on my Windows machine. Do you have an idea of the reason of this difference ?

Not being able to use the perception rendering method when you go from proPhoto to sRgb is something so strange.

Thanks
Nicolas

Hi Nicolas,

The Color Space profiles do not seem to work correctly in ColorThink Pro. Interestingly, they can be brought into the older ColorThink 2.3 and graphed just fine. This must be a bug in ColorThink Pro.

These profiles are not very common. I know of only 3 in existence and two of those are the ones you’re talking about. Note that it is the fact that these are Color Space profiles that are causing this issue - it’s not that they are version 4 profiles that is causing the problem. Other version 4 profiles work just fine in ColorThink Pro.

Especially if they are in beta form (but even if they are not) I am sure the creators of these profiles would appreciate your feedback on your use of the profiles. Feel free to contact the email addresses given on the www.color.org pages concerning these profiles. They would probably be able to answer your question about the gamut differences too.