How do you know if your color is off?
There are a few ways to know if your color is off. You can take a picture using the Macbeth Color Checker Chart as I did in the photo above. Then you can use the densitometer built into PhotoShop or Lightroom to compare each color patch the numbers for RGB.
Skin Tone: The telling sign of good color
The first giveaway to the human eye that the color is off will most likely be skin tone. Look at these photos here. I let the camera figure it out for the first one, which is acceptable on Auto White Balance. Look at the ones following.
There are times when a person is surrounded by dominate color, like a red wall. This will tell your camera that you are seeing in red light and will try an compensate giving your subject a cyan tone to their face.
I have done photo shoots where I used strobes and still needed to do a custom white balance because the ceiling, floor or walls were all creating a color cast that made the skins tones not look correct.
You can find online skin tone swatches that you can compare a person's skin to an approximate ethnicity color swatch. The RGB value for Caucasian skin is: R:239, G:208, B:207. Now the numbers may be darker or lighter do the the light on the skin, but the numbers will generally go up and down uniformly.
Here is a link to the Curvemeister website showing you how to use the skin swatch system to see if you are close for the right white balance in a photograph.
My recommendation is to shoot RAW but in every situation always get a custom white balance.
Look for upcoming Part 3