Corrective Coloring
I was having trouble taking the yellow out of a picture I wanted to use for an icon, and I went to my friend asking, "You remember when you told me a little green over patches of red would help even out the color? What do I do for yellow?" She then gave me the answer using the tips and tricks she learned about applying make up to herself. I realized that if I wasn't sure about this, then someone else might not know either. So this should help a little.
At one time or another we all want to conceal some type of nasty imperfection on our face, and we do it with the help of corrective make up. Now you can't slather on colored concealers onto your icons, but you can use layers to add neutralizing colors in the same way.
Neutralizing colors are colors that appear opposite on the color wheel. For example- blue neutralizes orange, green neutralized red and so on. So in order to cover red blemishes and blotchy skin, you must neutralize the color first with a green layer. How dark or light the layer you add will be decided by how much correction is needed. If the red to be neutralized is a light pink, you would use a corresponding light green.
Typically you will use one of 3 color choices - green, yellow, and lavender (mauve). You need to understand which color concealer will neutralize the flaw. Look at the flaw you want to cover. What color is it? Is it acne (red) or under-eye circles (blue)? By identifying this first, you will be able to pick which corrective color will make the best layer.
Here's a list of corrective colors and what they neutralize:
1. Yellow: Used to conceal bluish bruises, under-eye circles and mild red tones on the face.
2. Lavender: Used to normalize yellow-colored imperfections such as sallow complexions and yellow bruises. It can also help conceal very dark under-eye circles and dark spots on bronze skin tones.
3. Mint Green: Used to neutralize red tones on the skin. Use this for covering blemishes, red blotches, rosacea, port-wine stains.
If there is just a small area needing coverage, I find it's best to create a new raster layer and air brush the color with the density and opacity turned down on the airbrush. Once the color is applied, I then use the Gaussian blur effect on a setting of about one to blend. Then I set the layer to a number of different blend modes to find the best fit. Sometimes soft light works, sometimes it's best with saturation. Of course, if it's a large area you're trying to correct, flood filling the new raster layer also works.
What flaws can you correct using this method? Any number of them, including: under eye circles, sallow or yellow complexions, dark spots, bruises, acne, red blotchiness, rosacea, and even the effects of a night of partying. In some cases, you can even cover a tattoo. If the tattoo is a simple blue ink line drawing, you can use a corrective layer of yellow, and then a second layer of that of skin tone. It's really just a matter of trial and error mixed with patience.
Hope this becomes some help to your icon making.