This article explains that color is a perception created by light of certain wavelengths. The human eye detects light in the range of 380 to 800 nm. Colors arise from reflected or scattered wavelengths; cameras use the RGB system based on the eye’s three types of cones. White balance is important because light sources have different spectra. Spectral colors correspond to the colors of the rainbow, while mixed colors like magenta do not occur in the spectrum.
Category: Photography Basics > 5. Color & Light Article ID: 5.1 Created: May 2026
Key Points in Brief
- Color is not a property of an object, but a perception: light of certain wavelengths hits the eye, and the brain interprets it as color
- The human eye perceives light between 380 and 800 nanometers wavelength – this is the visible spectrum (rainbow colors)
- Cameras and screens use the three primary colors red, green, and blue (RGB) – because the eye has exactly three receptor types for these ranges
Explanation
What Is Light?
Light is electromagnetic radiation. The wavelength determines which color we perceive:
| Wavelength | Perceived Color |
|---|---|
| 380–400 nm | Blue-Violet |
| 400–470 nm | Blue |
| 470–560 nm | Green |
| 560–600 nm | Yellow |
| 600–630 nm | Orange |
| 630–800 nm | Red |
Below 380 nm is ultraviolet (UV) – invisible to the eye. Above 800 nm is infrared (IR) – also invisible, but felt as heat.
White light contains all wavelengths mixed. A prism (or raindrop in a rainbow) separates the light into its spectral colors.
How Do We See Colors?
The human eye has three types of color receptors (cones), each especially sensitive to red, green, and blue. The brain calculates the color impression from the ratio of these three signals.
Therefore:
- Red + Green → the eye sees yellow (even though no “real” yellow light is present)
- Red + Blue → the eye sees magenta/purple
- Green + Blue → the eye sees cyan
- Red + Green + Blue → the eye sees white
Digital cameras and screens use exactly this principle: three color channels (RGB) are sufficient to simulate almost every perceivable color to the eye.
How Is the Color of an Object Created?
When light hits an object, it can:
- Be reflected (bounced back)
- Be absorbed (taken in, usually re-emitted as heat)
- Be scattered (deflected in many directions)
- Be transmitted (through transparent materials)
The color we perceive arises from the reflected or scattered wavelengths:
| Object | What Happens | Perceived Color |
|---|---|---|
| Ripe Tomato | Absorbs everything except red | Red |
| Blue Sky | Blue light is scattered more strongly | Blue |
| Black | Everything is absorbed | Black |
| White | Everything is reflected/scattered evenly | White |
| Gray | Everything reflected and absorbed equally | Gray |
| Mirror | All wavelengths reflected evenly | No color impression, only reflection |
Why Does an Object Appear Different Under Wrong Lighting?
A red tomato under pure blue light appears dark – because it absorbs the blue light and no red light is available to be reflected. This is why white balance is so important in photography: different light sources have different spectra, and the camera must know which wavelengths represent “white.”
Spectral Colors and Rainbow Colors
The complete visible spectrum from 380 to 800 nm corresponds to the colors of the rainbow:
Violet – Blue – Cyan – Green – Yellow – Orange – Red
These are also called spectral colors. Colors like magenta or purple do not appear in the spectrum – they arise only through additive mixing of red and blue in the brain.
Practical Tip
In image editing programs (including Paint), you can directly experience color mixing: manually enter RGB values and observe what appears. (255, 0, 0) = Red, (0, 255, 0) = Green, (0, 0, 255) = Blue, (255, 255, 0) = Yellow, (0, 0, 0) = Black, (255, 255, 255) = White. This experiment illustrates additive color mixing better in a few minutes than any explanation.