Your screen is lying to you about yellow. Every color you see on a monitor, phone, or TV is built from just three: red, green, and blue. RGB is an additive color model, which means colors are created by adding light together. Combine all three at full intensity and you get white. Turn them all off and you get black.

This is the opposite of how paint works. Mix red and green paint and you get a muddy brown. Mix red and green light and you get yellow. That difference trips up a lot of people moving between print and screen design. CMYK, the subtractive model used in printing, starts with white paper and subtracts light by absorbing certain wavelengths. RGB starts with darkness and adds light.

How RGB values work

• Each channel ranges from 0 to 255 in standard 8-bit color
• Pure red is (255, 0, 0)
• White is (255, 255, 255)
• Hexadecimal shorthand like #FF0000 encodes the same values

Modern displays pack millions of tiny red, green, and blue subpixels into each screen. Sit close enough to an older LCD and you can see them. Your eye blends the light from those subpixels into every color you perceive. RGB is not a property of objects. It is a recipe for light.