Re: [Lcms-user] odd change in 2.13

[Marti M. <mar...@li...>]

Hi,


> On 22 Mar 2022, at 23:10, Derek B. Noonburg <de...@gl...> wrote:
> 
> I'm seeing very different output in one particular case, after
> upgrading from 2.12 to 2.13 (or 2.13.1).
> 

Checked your profile and gives same results to me, tested on Debian 11, system lcms2 (from Debian, which is 2.12) vs. compilation of 2.13 on /usr/local

marti@debian:~$ /usr/bin/transicc -c1 -s -ex -i profile.icc -b -t1
LittleCMS ColorSpace conversion calculator - 5.0 [LittleCMS 2.12]
Copyright (c) 1998-2020 Marti Maria Saguer. See COPYING file for details.

Enter values, 'q' to quit
R? 97
G? 97
B? 97

R=0x9F G=0x9F B=0x9F 

Enter values, 'q' to quit
R? q
Done.
marti@debian:~$ transicc -c1 -s -ex -i profile.icc -b -t1
LittleCMS ColorSpace conversion calculator - 5.0 [LittleCMS 2.13]
Copyright (c) 1998-2022 Marti Maria Saguer. See COPYING file for details.

Enter values, 'q' to quit
R? 97
G? 97
B? 97

R=0x9F G=0x9F B=0x9F 

Enter values, 'q' to quit
R? q
Done.

Should I use your exact program to reproduce the issue? The transicc utility does basically same.

BTW I have checked ColorSync utility on relcol to sRGB. ColorSync does not have black point compensation, but turning it off on both sides, they agree on same value: 30

Regards
Marti

 

> The input profile is from a PDF file, and claims to be e-sRGB.  With
> INTENT_RELATIVE_COLORIMETRIC and cmsFLAGS_BLACKPOINTCOMPENSATION, the
> transform to sRGB (builtin profile) produces completely different
> results.
> 
> The code looks like this (error checking and cleanup intentionally
> omitted):
> 
> #include <stdio.h>
> #include <lcms2.h>
> 
> int main() {
>  cmsHPROFILE inputProfile = cmsOpenProfileFromFile("profile.icc", "r");
>  cmsHPROFILE outputProfile = cmsCreate_sRGBProfile();
>  cmsHTRANSFORM xform = cmsCreateTransform(inputProfile, TYPE_RGB_8,
> 					   outputProfile, TYPE_RGB_8,
> 					   INTENT_RELATIVE_COLORIMETRIC,
> 					   cmsFLAGS_BLACKPOINTCOMPENSATION);
>  unsigned char in[3] = {0x61, 0x61, 0x61};
>  unsigned char out[3];
>  cmsDoTransform(xform, in, out, 1);
>  printf("%02x %02x %02x\n", out[0], out[1], out[2]);
> }
> 
> and I'm attaching the profile.
> 
> The results with 2.12 are "1e 1e 1e" and with 2.13 (same with 2.13.1)
> are "9f 9f 9f".
> 
> I pulled the profile out of a PDF file, so it's possible there's a
> problem in the profile itself -- but I'm not seeing any error messages
> from LCMS if I use cmsSetLogErrorHandler.
> 
> If anyone has some idea of what's going on here, I'd love to know.
> 
> Thanks!
> <profile.icc>_______________________________________________
> Lcms-user mailing list
> Lcm...@li...
> https://lists.sourceforge.net/lists/listinfo/lcms-user