[argyllcms] Re: Printing using an ICC profile
- From: "Alastair M. Robinson" <profiling@xxxxxxxxxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Thu, 21 Jan 2010 18:28:22 +0000
Hi :)
Pedro Côrte-Real wrote:
I assumed that the idea was to use the monitor profile to try to match
the screen.
Not exactly - while it would be possible to convert images first from
source profile -> monitor profile, and then from monitor profile ->
printer profile, every conversion causes some loss of information, so
most software, PhotoPrint included, tries to avoid unnecessar conversions.
PhotoPrint uses a Source -> Monitor transform to display images, and a
separate Source -> Printer transform to print them - so it's the source
profile you should provide to colprof.
I redid the test with sRGB and the result was pretty much
the same.
OK
But then do I need to convert the image to this v4 sRGB before giving
it to photoprint or will it do that itself?
If you do decide to experiment with those profiles, you want the V2
variants at the bottom of the page, not the V4 version.
But no, you don't need to convert the images to the black_scaled profile
- the point of using a different source profile is to interpret the
image data differently. sRGB is a theoretical colour space with a
"perfect" black. The black_scaled version of sRGB is a version of the
same thing, but with a "typical" imperfect black (as found on real-world
monitors and printers) which causes Argyll's gamut mapping to behave
slightly differently. I've found in some cases that difference is
beneficial to skin tones.
I'm guessing that is probably it.
If you set PhotoPrint's display mode to "Simulate Print", then do a
print preview (which goes full-screen, thus removing all distracting
white-point cues from the display) then look from the on-screen version
to the printed version, are the skin tones markedly different between
screen and print? If so, the problem is likely to be profile accuracy.
(Don't try to hold the print beside the screen and look at both
simultaneously - that rarely works without laboratory conditions!)
Thanks for the help,
No problem :)
All the best
--
Alastair M. Robinson
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