Swapped red and green ICC not un-swapping when soft-proofing about little-cms HOT 6 CLOSED

Hi,
It works to me, tried transicc command line:

C:\Users\mmaria\Desktop\test>transicc -o SwappedRedAndGreen.icc -p "sRGB Color Space Profile.icm"
LittleCMS ColorSpace conversion calculator - 4.3 [LittleCMS 2.08]

Enter values, 'q' to quit
R? 0
G? 100
B? 0

R=99.9939 G=-0.1144 B=-0.0254

Maybe you are trying to softproof the appearance of SwappedRedAndGreen.icc profile?
If so, no channel should be swapped. The profile converts to a GRB space and back. As long as you work in this GRB space, the image looks ok.
BUT If you display the GRB numbers in a RGB space, you see the channels swapped, but this is your fault, not an issue on the profile.

Regards
Marti

from little-cms.

I'm not sure we understood each other.

My assumption is that if I set the SwappedRedAndGreen.icc profile in RawTherapee as the monitor profile (when red and green are swapped, the image looks funky) and as the output profile, and enable soft-proofing, then the final preview will look correct, because the output profile will swap the colors once, and the monitor profile will swap them again. Is the assumption wrong?

If that assumption is wrong, how then do we check that soft-proofing is working correctly? Is there any other trick which would make this obvious, as obvious as swapped (or not swapped) color channels?

from little-cms.

Ok, having read Beep6581/RawTherapee#3406 I now understand better the issue.
You are assuming that a softproofing of this profile will show swapped channels, and this is not true.
As said, the profile converts to a GRB space. The swapping occurs when you use a RGB space instead of the space that is providing the profile (GRB). But then, softproofing does not know about you are tricking.

To check soft proofing, just use any profile with small gamut. Any CMYK, like SWOP. The changes on colors are quite evident.

from little-cms.

Thank you @mm2

from little-cms.

Welcome!

from little-cms.

By the way, I feel like I abused GitHub a bit by asking here (but its nice being able to @tag people and not having to register for a new account ;) ). Is there a better place to ask such questions, or is it ok with you if I used GitHub in the future?

from little-cms.