I usually to skin adjustments in Color Balance. Watch the info palette and shoot for a nearly equal balance between yellow and magenta, with a slight edge given to yellow for a normal skin tone. Of course, a little cyan will be present and it must also be adjusted on occasion. Some people can be very difficult to bring into a normal range. Here is a post from Kevin Brekenridge that I saved about 3 years ago. Hope it helps:

Matching skin tones has driven many scanner operators into retirement.

There is no magic formula or CMYK breakdown, but here are some general rules that have worked for me over the years.

First let me state the obvious, every person has a unique skin tone color, even within specific ethnic groups the variety is limitless. Unfortunately CMYK, and offset printing only allows us a fraction of choices, and equally unfair you are often forced to stereotype people with specific CMYK break downs to trigger those every present memory colors hard wired in our brains.

Take a look around the room, Caucasian, Asian, African American, Hispanic, East Indian, and Native American, all in reality don't have nearly the saturation of color we see in photographs and publications. So we have to cheat a little to give these images some punch, after all who wants a bunch of pasty smiling people on the cover of their magazine anyway!

A good rule of thumb for most skin tones is to have the magenta trail the yellow and the cyan trail the magenta, very little black even in African American people. Black should only serve to add density to a prominent shadow areas, if you have too much it will neutralize what color you have when it hits the press, those pressman always run up the Black so the text looks sharp.

Here come the stereotypical portion of color correcting skin tones:

When I set up a scan for Caucasian people the Magenta trails the Yellow slightly and the Cyan in less than half of the Magenta.

If I sample a quarter tone area the CMYK might look like this: Cyan: 10 Magenta: 25 Yellow: 30 Black: 0

Asian people get a little more of everything plus a slightly higher separation between the Magenta and Yellow.

If I sample a quarter tone - mid tone area the CMYK might look like this: Cyan: 15 Magenta: 35 Yellow: 45 Black: 0

African Americans and people with darker skin tones get a slightly warmer treatment with enough cyan to keep it from going to red on press.

If I sample a mid tone area the CMYK might look like this: Cyan: 25 Magenta: 47 Yellow: 55 Black: 5

The big trick is to mix it up a bit, I don't shoot for these numbers every time, I like to ensure the scan prints as close to the original as possible after all that's what a scanner operator gets paid to do, but if I have some creative license or the photo has poor color and overexposed, I apply these guidelines. I also watch the 3 quarter tones and shadow areas very closely, making sure they don't over saturate and become dominant. The skin tones should have a consistent Hue regardless of the values from highlight to mid tone to shadow. Don't make the highlight Yellow, the mid tone Brown and the shadow Red.

John_Wilkinson

Replied in the following topics

best way to fix yellow skin