On Sep 13, 2005, at 8:30 AM, Godfrey DiGiorgi wrote:
The A-RGB profile does represent a substantially larger gamut.
I did the following plots a while ago for a friend of mine. These
were done using the "high quality" profiles available on Epson's
website.
Adobe RGB plotted against the Epson 2200 (umm, premium glossy paper I
think... or maybe semigloss):
http://www.digistar.com/~dmann/temp/epson_adobe.jpg
And the same with sRGB instead:
http://www.digistar.com/~dmann/temp/epson_srgb.jpg
Those plots came from the ColorSync Utility that comes bundled with
the Mac OS. You can compare any two profiles and rotate them around
in 3D.
Note that the colours shown are only an indication of which colour
channel is in which direction. They don't represent actual colours
within the colour space.
In both cases the grey wire-frame is the Epson profile. You can
probably see the disadvantages of using an RGB colour space to edit
and a CMYK device for printing :) The limit of what's available from
the output stage of the workflow (ie printing) is defined by the
intersection of the two volumes.
Just for kicks, I did some large-gamut comparisons as well:
Ektaspace:
http://www.digistar.com/~dmann/temp/epson_ektaspace.jpg
Kodak Pro Photo RGB (I had to make the Pro Photo one grey here, as it
envelops the Epson profile completely):
http://www.digistar.com/~dmann/temp/prophoto_epson2.jpg
I won't go through the ins and outs of one working space vs the
other, or even large vs small. It'll take me too long and it depends
a lot on your intentions for input, editing, archiving and printing
and for most people it's all academic anyway. If your screen is
calibrated and your workflow is set up OK, then for most purposes it
won't matter which colour space you choose.
The crux, though, is how well the profile conversion to the printer
does the job. The latest print drivers seem to be working more
smoothly.CS2's print system does seem to do a better job, with less
adjustment necessary, than CS did. Perhaps Adobe's continued
development has improved things as well.
I use PS for my whole colour workflow, but PS is the only colour-
critical app I use. I've yet to be disappointed with the colour
rendering of a print from my printer, except once when some nozzles
clogged and I lost all yellow :)
- Dave
