Final answer:
To create a skin tone with primary colors, mix red and yellow to make orange, then add a bit of blue and adjust with more primary colors as needed. For lighter tones, use less blue; for darker ones, add more blue or use a brown base made by mixing all three primary colors.
Step-by-step explanation:
To make a skin tone using only the primary colors red, yellow, and blue, start by mixing equal parts of red and yellow to create orange. Then, add a small quantity of blue to darken the tone. Adjust the color by adding more red or yellow for warmth, or more blue for a cooler shade. Since pure black can be challenging to create with primary colors and may result in a brownish tone, use this to your advantage for creating neutral colors that are often found in various skin tones. To achieve lighter skin tones, mix in white (if available), or use less blue and more red and yellow. For darker tones, incrementally add more blue or create a brown base by mixing all three primary colors and alter the hue as needed.