[argyllcms] RGB Printer profiling and ColorSavvy CM2C
- From: "Alastair M. Robinson" <blackfive@xxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sat, 30 Jul 2005 12:34:43 +0100
Hi,
I'm fairly new to Argyll and I'm trying to get my head round colour
management in general.
I have a ColorSavvy CM2C colorimeter, which is a device that must be
placed by hand over each patch to be measured. ColorSavvy have an SDK
available on their website which make it very easy (using a DLL) to read
XYZ values from a printed target.
My primary interest is in RGB printer profiles, and so far I've played
with Profile Prism (using an Epson Perfection 640 scanner as a
poor-man's colorimeter), Argyll (both with the above mentnioned scanner)
and Colour Confidence Print Profiler (which came with my ColorMouse).
Prism does absolute wonders on matte paper, but seems to struggle a bit
on glossy. It also generates non-free profiles, which is unfortunate.
Print Profiler's gamut-mapping strategy seems to be "preserve luminance
at all costs", which leads to very washed out greens.
Argyll looks very promising, but I've obviously got to learn a lot to
make best use of it!
Now we come to my questions:
Is there any special reason for the apparently random placement of the
colour patches on the page? (It makes scanning the patches with the
colormouse an "interesting" task, since with no software support, the
XYZ values have to be added to the .ti3 file by hand...)
Does Argyll have to generate the target itself, or can the patches be
"hand-picked" or augmented? I ask because in my experiments last night
I got a remarkably good result with a mere 60 patches - much smoother
than either Prism or Print Profiler.
What I'd like to do is use a sparse scattering of patches, and then
augment this in the "difficult" areas, adding some extra patches down
the grey axis and in typical skin tones.
Finally, with both Argyll and Print Profiler (and to a much lesser
extent, Prism as well), images printed using the generated profile
generally have very good hue and saturation, but need further gamma
correction to get the luminance looking "right" - in terms of Gutenprint
controls, Composite Gamma needs to be increased to 1.1 - 1.15 or so.
Any idea what's causing this?
Thanks in advance,
--
Alastair M. Robinson
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