When light strikes a surface, whether it be a building, landscape, or face, the outcome depends on the texture, tone, and color of the material, as well as the angle and color of the light.
If the material is opaque, like metal or brick, some of the light is reflected, while some is absorbed. Darker materials reflect less light, so a black object in the sun will heat up more than a shiny silver one.
Colored materials reflect their specific color wavelengths and absorb most of the other wavelengths. For example, blue paint reflects blue and absorbs red and green from white light. Under a red light, a rich blue will appear almost black because the blue paint cannot reflect red light.
Understanding these effects is crucial for using color filters effectively. You can also modify colors during post-production if you scan the negative and use digital printing software. The surface finish greatly influences light reflection as well.
A matte surface, like eggshells, drawing paper, or dry skin, scatters light evenly, making the angle of incidence less significant. However, a smooth, shiny surface, like crystal or glossy paint, behaves like a mirror and reflects most light in a single direction, known as specular reflection.
If light strikes a shiny surface at a right angle, it reflects back along its path, creating a bright spot, such as when a flash hits a glass window or glossy wall directly. To avoid glare, adjust the lighting direction or the camera angle to redirect the reflective light away from the camera when photographing highly reflective surfaces.
