On Sep 12, 2005, at 12:49 PM, [EMAIL PROTECTED] wrote:
Thanks Godfrey. I was wondering why you didn't respond immediately.
You've been busy <g>. What you posted before sounded complicated
because it was detailed. I tend to oversimplify. I appreciate the
clarification and your evaluative tests. I've always wondered if I
was losing a lot with my color space. Apparently, if there's any
loss, it's minor. I have tried Colorsync color settings with Adobe
98 color space, and the results were not pleasing. I will try the
North America Prepress settings one of these days, but I'm always a
little leer of change when things are going well.
You're welcome. I tend to err on the side of detail and precision...
it's the Mathematician/Engineer breaking out. ;-)
The only way to really know what works best is to test and experiment
with the printing system you're going to be using, and with photos
typical of what you're going to print. That is really the bottom line.
Regards the differences between A-RGB and sRGB colorspaces:
The test photo was an average snapshot/group photo taken in my
partner's house in Tijuana ... available light, a lot of light color
walls, four people's skin tones, camera triggered remotely. Not
stressing the color envelope very much. I happened to be looking at
it and wanted a few prints anyway...
The R-G toes on that set of comparison histograms demonstrate some
clipping in those channels on the conversion to sRGB, but the effect
on the photo is relatively small because the photo doesn't stress
reds and greens very strongly. Only the skin tones move a little bit.
I'll probably repeat the test with some roses and leaves and a
Macbeth color checker chart (I do this once in a bit to see if the
inks/paper calibrations are working...) once I can find my chart
again. It seems to have gone walkies since my move in April. Anyway,
I suspect that the chart will show more significant deviations in the
print output between the sRGB and Adobe RGB profiles. The A-RGB
profile does represent a substantially larger gamut.
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.
Godfrey
