Paint pigment works by selectively absorbing and reflecting light wavelengths; the color you see is the light that the pigment doesn't absorb.
How Pigments Give Color: The Mechanism
At its core, the color we perceive from a paint pigment is a result of how the pigment's molecules interact with light. When light, which contains a spectrum of different wavelengths (colors), hits a pigment particle, certain wavelengths are absorbed by the pigment, while others are reflected.
Pigments absorb certain wavelengths of light due to energy levels in their molecules that match the energy of specific light wavelengths. This absorption is a molecular process where the energy from the light is taken in by the pigment's structure.
The color that we see when we look at the pigment comes from the reflected wavelengths of light the pigment does not absorb. For example:
- A pigment that appears red absorbs most wavelengths (greens, blues, yellows, etc.) but reflects primarily red wavelengths.
- A pigment that appears blue absorbs most wavelengths (reds, greens, yellows, etc.) but reflects primarily blue wavelengths.
- A pigment that appears black absorbs nearly all wavelengths of light.
- A pigment that appears white reflects nearly all wavelengths of light.
Why Different Pigments Have Different Colors
The specific wavelengths that a pigment absorbs and reflects are determined by the chemical composition and structure of the pigment molecule. Different molecular structures have different energy levels, which means they will resonate with and absorb different specific wavelengths of light. This is why, for example, the molecular structure of a cadmium red pigment is different from that of an ultramarine blue pigment, leading them to absorb and reflect different parts of the light spectrum.
In essence, the color of paint pigment isn't inherent in the pigment in the absence of light; it's a property that emerges from the interaction between the pigment's molecular structure and the light that illuminates it.
