One thing I’m noticing is that colour profiles are crucial when working in Mac Photoshop, even if the final product is meant for on-screen display.
A long-time trick/crutch of mine on Windows was the screen capture. Alt + PrntScrn grabs a shot of the active window to the clipboard, which is easily pastable to a Photoshop canvas. I never even thought about it, I just did, and I did a lot.
Because the Mac handles screenshots a little bit differently (Cmd + Shift + 4 dumps a user-defined area to a PDF file, instead of the clipboard) I’ve had to start importing the screenshot instead of pasting it. This involves a dialogue asking if I want to save or discard the colour profile attached to the document.
I’m getting hung up on this is when I can’t remember which instances require using the embedded profile, and which involve converting to the working space. I’ve configured my default working space in Photoshop to ‘Color LCD’ which seems to keep input and output consistent relatively, but OS X saves each screen shot to ‘Generic RGB Profile’ which produces a mismatch warning. By discarding the profile attached to the file and just using my default colour space, I’m theoretically working with the raw pixels, non-corrected.
I’m still not confident I’ve got it though. Above is a shot taken as I was struggling to figure out which settings keep the colour consistent. The blues on the top are warmer, almost purple compared to the blues on the bottom. The top shot half is the screen shot, the bottom is the actual dock. Subtle difference, but this can be a big deal when you’re dithering for transparency and colour-matching. Consistency is really important.
It strikes me as rather odd, though, that working solely with on-screen imagery requires such juggling of colour modes. Especially when I never had to think about it on Windows.
update: Brian Warren points out that Cmd + Ctrl + Shift + 4 copies the screen shot to the clipboard instead of dumping it to a file. Pasting that into an open document seems to alleviate any profile matching problems with screen shots. Excellent!