Re: My picture looks fine in Photoshop, but when I post it onthe Web the colors are o
Folks, note that this thread was originally posted in September 2010. Since then, in the past three years, lots has changed.
Since then, the major internet browsers (ie, IE, Safari, & Chrome) have all incorporated color management, as Firefox has had for many years. This means that if your file is in any of the common working color spaces (eg, sRGB, Adobe RGB, ProPhoto, Apple RGB, ColorMatch RGB, and possibly a few others), all four of these browsers will display an image in any of these spaces correctly.
Obviously, if for some bizarre reason, you incorrectly use either an input or an output *device* color profile (eg, a printer/paper profile, a scanner profile, a camera profile, etc.) as your working color space, no browser will recognize it, and it will almost certainly be displayed as if the numbers in that file represent colors in the default sRGB space, so people will see some truly bizarre colors.
With respect to CMYK, I haven't tested how the major browsers handle all the different flavors of CMYK, but as almost all of these should be considered output device or soft proofing profiles, not working spaces, I wouldn't risk posting on the web in any CMYK space.
The bottom line is that even in spite of the improvements that have been made to browsers, the safest approach is still: No matter what space you prefer to work in, ALWAYS *CONVERT TO* sRGB as your last step (not "assign to"), and save a copy of the result for posting on the web.
FWIW, personally, I never use the "do not color manage" option because I want to know exactly what space I'm working and make my choice explicitly instead of doing what essentially amounts to sweeping the issue under the rug and not speaking about it.
Just my $0.02,
Tom M