Re: [Lcms-user] Some colours appear wrong

[Robert B. <ro...@be...>]

Thanks Kevin,

One of our next steps was to look at an alternative CMS, so knowing it affects commercial 
ones as well is very useful. I'd prefer to continue using LCMS anyway!

How did you edit the red curve? Is there an easy way or do I need to rapidly learn the ICC 
specification? Do you know of any software that might help?

Rob.


kev...@ho... wrote:

> I had the same experience using several commercial ICC packages too...
> 
> A color scientist at my last company explained that it was a failing of the
> ICC specification itself (in the way transforms were calculated), but I
> dont' know if that's 100% correct.
> 
> Our solution was to hand-edit the red curve... not a scientific process as
> much as an artistic one, sorry!
> 
> Kevin.
> 
> 
> ----- Original Message ----- 
> From: "robert bergs" <lit...@be...>
> To: <lcm...@li...>
> Sent: Monday, August 18, 2003 6:57 AM
> Subject: [Lcms-user] Some colours appear wrong
> 
> 
> 
>>I am using Little CMS to profile a Kodak i260 scanner using the Kodak IT
>>8.7/2-1993 target. In use LCMS is brilliant - I found it very easy to
> 
> create and
> 
>>use the colour profiles. On the whole the results are great, but for one
> 
> problem:
> 
>>I have found that areas of bright red on the original piece are being
> 
> converted
> 
>>to a bright orange after they have had my profile applied. I am using the
> 
> sRGB
> 
>>space as the output profile.
>>
>>I followed the advice that Hugh Brackett posted to this list a few days
> 
> back
> 
>>(thanks, Hugh) - but the scanner's interface is very poor and does not
> 
> allow me
> 
>>to alter the Gamma, shadow, highlight or even brightness and contrast. All
> 
> I can
> 
>>do is select one from 5 'color tables' geared up for photo or text scans.
> 
> The
> 
>>setting named 'Mixed2' gave the most even histogram and a dE of 2.08.
> 
> Applying
> 
>>the profile to the original IT8 scan does give visually pleasing results,
> 
> and
> 
>>most images come out fine. It's just the bright reds that are wrong.
>>
>>Has anyone else experienced a similar problem? Is it possible to 'tweak'
> 
> the
> 
>>profile to fix this? Could it be a bug in lcms? Or am I just doing
> 
> something wrong?
> 
>>Any advice would be greatly appreciated,
>>
>>Robert Bergs
>>
>>
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> 
>