Color and light
Color is reflected light
When we see color, we are actually looking at reflected light. When illuminating an object or scene, a light source emits a spectrum of colored wavelengths. For example, sunlight emits a spectrum including infrared, ultraviolet and all visible wavelengths, whereas candlelight emits only red, orange, yellow and infrared wavelengths, giving everything it illuminates an orange cast.
When a scene or object is illuminated, some of the light source’s wavelengths are absorbed and some are reflected. The reflected wavelengths create what we perceive as color. If no light is reflected (or if there is no illumination), the scene or object looks black.
The color of an object depends on two factors – the color of the light source and which wavelengths of light the object reflects. To view the true color of an object, we must illuminate it with a light source that includes all the wavelengths that the object will reflect. For example, if a light source only emits a partial range of wavelengths, an object’s true color may not be visible. For example, if we shine a light source emitting red, green and blue wavelengths at a red strawberry, then the green and blue wavelengths will be absorbed and the red wavelength will be reflected. This means that the strawberry will appear red. However, if only green and blue wavelengths are emitted, they will both be absorbed and the strawberry will appear black.
You can read more about different types of light sources later in this chapter.