Red pigment reflects red wavelengths of light. Pigments appear as certain colors because they absorb some wavelengths of light and reflect others. Red pigment absorbs all colors of light except red, which it reflects back to our eyes, making it appear red.
For example, if you shine white light on a red object, the red pigment in the object absorbs all colors except red. The reflected red light is what we see.
It's important to note that red pigment doesn't reflect only a single wavelength of red light, but rather a range of red wavelengths. However, it primarily reflects red wavelengths, giving it its characteristic appearance.
