Re: Pre-color-management scans legacy
Re: Pre-color-management scans legacy
- Subject: Re: Pre-color-management scans legacy
- From: Stephen Marsh <email@hidden>
- Date: Sat, 05 Jan 2002 17:51:49 +1100
Paul wrote:
>
> The scans were actually made using the fixed end points. I was wrong
when I mentioned previously that I had used the scanner calibrated
profile. In fact I recall now scanning using the LUTID ICC table. <<
If I am not mistaken, using the fixed endpoints and scanning with the
LUTID ICC table are the precise 'dumbed down' steps used for making a
custom profile. How different the custom generated profile is from the
LUTID ICC table I don't know - but this would seem to be the right
profile to assign (I am presuming that they are one and the same in
regards to colour/tone).
Anyway, it is easy to assign the custom scanner profile to these legacy
scans - it should be immediately obvious if this is the correct
description of the RGB legacy data or not.
>
> I must say that I had to apply heavy corrections through the curves layer in order to have a good image in the first place. <<
From limited experience with the LUTID ICC on the Supreme (I have not
made a custom profile) - this is a 'raw' profiling scan setup, with most
options disabled. It provides a flat, untoned scan - which might be
'similar' in concept to using linear raw acquire in some digicams.
Although not 'ideal', we use the canned profiles to describe
reflective/transmissive RGB input - the LUTID ICC table is not used for
our normal workflow.
Since you have profiled the system - can you compare the custom profile
to the canned ref/trans profile? Can you scan the same image twice, with
the same fixed endpoints etc, with two different input profiles (one
cannned, one custom). I am just interested in how close the
canned/custom profiles are on the Jazz model, as I can't make this
little test on the Supreme. This is not important, I'm just curious.
In your reply to Andrew Rodney, you mentioned that assigning the custom
profile does not work. This is what I am suggesting above. As you
mention, the LUTID ICC is a proprietary table, but the custom profile
should simply reflect this state (but I might be missing something here,
as I have not performed any custom profiling on the scanner).
And as for having issues with your original workspace RGB files
converting to WWW images in sRGB - as mentioned before, this seems
weird. Can you crop out a section of the original that has bad colour
shifts, tag it, and save it for me to play with? Are you using
perceptual rendering in the transform from WS RGB to sRGB? Is BPC being
used in the transform?
Sincerely,
Stephen Marsh.