Converting/assigning profiles

Question

I've been experimenting with various settings in CS (on a mac OS X) and reading this forum (as well as G Ballard's helpful website). Could someone clear up a few questions for me:
I read on GBallard that I should honor the source file's embedded profile. And that the file's source space should equal PS working space. Also, sRGB is the preferable space for both (am I wrong in that?). My main confusion is in trying to align the file and PS spaces.
-- in PS working space settings, if I choose US Prepress Defaults as recommended, it automatically chooses Adobe RGB for working space. Should I leave it on this setting, or should I change working space RGB to my monitor RGB (which then changes the setting to 'custom')?
-- Then -- what should my source space be? my photo files are tagged Camera RGB. Should I convert these files to the same space setting as the PS (such as sRGB)? I use images on both web and an epson R800.
Basically, I'm really confused about whether I should be changing color profiles at all. I initially started tinkering because my prints were so dark and muddy, and changing profiles seemed to help. (AppleRGB worked best, for some reason) I'm now more or less getting the results that I wanted, but I would really appreciate some guidance, so it doesn't feel so hit and miss.
(I have calibrated my monitor to 2.2 gamma 6500/D65 profile)
Thank you,
Keiko

Answer 1

Keiko,
One question at a time -
"I read on GBallard that I should honor the source file's embedded profile.
Yes. That means that when you open the tagged file (file with an embedded profile) you should have Photoshop either "Preserve the Embedded Profile" or "Convert to Working RGB." You set these in the Color Settings section where you should also check the boxes to have Photoshop prompt you for Profile Mismatches (the profile in the file is different from the Working Space that you have selected for Photoshop) when opening files and pasting and when opening files that have Missing Profiles.
Photoshop is "honoring" the file's profile when it "Preserves" or when it "Converts." In either case, it uses the file's profile to accurately determine the actual colors in the file. The profile lets Photoshop reference the file's RGB values against an "absolute" color space called CIE Lab to arrive at an accurate understanding of the colors.
When it "Preserves" the profile, it writes that profile back into the file when it Saves. When it "Converts" it writes its Working Space Profile into the file. Either way the color will be accurate. But I recommend Converting. That way a "standard color space" profile gets written into the file when you're done editing.
"And that the file's source space should equal PS working space."
No. You're misunderstanding something. The file's source color space is described by its profile. Read the above regarding Preserving or Converting the file's color space when bringing it into PS.
Also, sRGB is the preferable space for both (am I wrong in that?). My main confusion is in trying to align the file and PS spaces. "
No again. The file gets its original color space (created and assigned) by the device creating the file. That color space MAY be sRGB, or it may be some camera's proprietary profile.
But, sRGB is a good space to use as Photoshop's Working Space if you are primarily working on images destined for the Web.
Adobe RGB 1998 is also a good general purpose Working Space, especially if your images are going to be printed on a printing press. You can work in Adobe RGB 1998, then convert to sRGB before Saving for Web.
Working spaces constrain the decisions PS must make in "mapping" (converting) color information from source space (a digital camera) to destination space (monitor, printer). Without Working Spaces, PS would need to give inordinate importance to colors far out of gamut for the destination space, to the detriment of accurate representation of "less exotic," more "important" colors.
NEVER, NEVER, NEVER set Photoshop's Working Space to your monitor's profile. You may be able to get things set up so that you get consistent results looking at your images on your monitor, printing to your printer, but no one else will see the colors you "think" your images contain. Use Adobe RGB 1998, sRGB, ProPhoto RGB. These are all Device Independent spaces. Your monitor profile (color space) is unique to your monitor (Device Dependent).
"-- Then -- what should my source space be?"
Your Source Space is whatever profile your digital camera embeds in the file when it creates it.
"my photo files are tagged Camera RGB."
That's right.
"Should I convert these files to the same space setting as the PS (such as sRGB)?
Yes. See above.
"I use images on both web and an epson R800."
When you Save for Web you need to make sure you save the Web jpeg file in sRGB space, that is, Convert to sRGB as part of your workflow in Saving for Web. (You also should embed the sRGB profile in it. But the reality is that Web browsers, whether they understand ICC profiles or not, assume files are in sRGB space, whether they have an sRGB profile or not, and act accordingly on them)
If your PS Working Space is sRGB and you Convert files you bring into Photoshop to sRGB on opening, then no further conversion is needed before Saving for Web.
Whatever your PS working space, you will print to your Epson 800 through your Epson 800 ICC Printing Profile (either supplied as a "canned" profile from Epson, or a custom profile that you have generated or paid for through a profiling service). You let PS manage the color conversion involved in translating from its Working Space to the printer's Destination Space by selecting "Let Photoshop Determine Colors" under "File/Print With Preview/Color Management/Options.
That's a lot of information. Please read it several times. But don't hesitate to ask if something doesn't seem to click.
Rich