A lady wrote to me today to ask my advice about editing skintones in Photoshop Elements.
Her problem is shared by all Elements users - namely, the absence of CMYK numbers in the Info Palette. There are lots of tutorials on the web about editing skintones, but most of them advise doing it by the CMYK values. You know the kind of thing - "Cyan 1/3 of Magenta, Yellow slightly higher, etc".
How do you edit "by the numbers" if you don't have the numbers?
Well, the first answer is "by looking at the photo!" This might seem flippant, but seriously, it's possible to get so bogged down in "technical this" and "percentage that" that you forget to just look.
If your instinct says "that guy is too rosy" or "healthy people don't look as grey as that" or "she's too dark" or whatever, then that's what counts. Are people going to hang a little Info Palette beside your photo on their living room wall? Of course not. (Actually, that would be pretty funny!)
But, despite all that, I'm aware of the value of numbers. It's easy to start second-guessing yourself on skintones, and it's certainly easy to over-process and get lost in a mess of adjustments, and start to go insane. It's great to have numbers that you can check.
So, are Elements users doomed to insanity? No, of course not. You've got numbers - RGB ones.
RGB numbers aren't too hard to get used to. Broadly speaking, the rule is pretty simple: R>G>B. The Red value will always be higher than the Green value, which in turn will be higher than the Blue value.
Let's get a bit more specific. The Red value will usually roam between the mid-100s (in shadow areas) to mid-200s (in highlight areas).
The Green and Blue channels will usually roam from just under 100 to just over 200. What's important is the margin. The Green value will be an average of 20-30 points higher than the Blue value. If you keep that approximate margin, the colour of the skin will look good.
Please note that I'm talking about sRGB numbers here. If you consider yourself advanced enough to use Adobe RGB or ProPhoto RGB, then I would expect you to already be very proficient with skintones, and you don't need my help.
So don't despair that you can't afford a full version of Photoshop; and please don't think that you can't achieve great photos and great skintones in Elements. It's a powerful tool, and with a little practice, you'll be able to adapt CMYK-centric tutorials for your purposes.
Lastly, I want to say that people who truly understand how the R, G and B channels interact to make colour will become masters of their craft. CMYK numbers are not "real" values, and in the long run, will teach you very little about digital colour.
Please take a moment to read my Ramblings about skin, where you'll find some more useful information.