solarization

Solarization is a word used in a few fields, but its best-known meaning comes from photography. There, it describes an effect in which tones are partly reversed after very strong exposure to light, or after film or photographic paper is exposed to light during development. The result can look strange and striking, with bright edges and an almost negative-like appearance.

The word is also used more broadly for processes that use the sun's heat or energy. In agriculture, soil solarization means covering soil so the sun heats it enough to reduce weeds, pests, and some plant diseases. In some contexts, it can also mean changing something over to solar power.

Solarization is most often understood as a photography term, though it appears in a few other areas as well. In photography, it refers to a reversal or partial reversal of tones caused by very strong exposure to light. The word is also commonly used for a darkroom effect in which film or photographic paper is briefly exposed to light during development, producing an image with unusual contrast, glowing edges, and a mix of light and dark values that can feel both positive and negative at once. In careful usage, that darkroom technique is often called the Sabattier effect, though many people casually use solarization for it too.

Outside photography, solarization can describe the act or process of using the sun's energy for a practical result. In farming and gardening, soil solarization means trapping solar heat, usually under clear plastic, so the soil becomes hot enough to suppress weeds, pests, and certain diseases. In some modern usage, the word can also refer to converting a building, system, or area to solar power.

Across these meanings, the common idea is the strong action of sunlight or intense light. Sometimes that light changes the look of a photograph; sometimes it is used as a tool to heat soil or provide energy. In each case, solarization describes a change brought about by exposure to the sun or to powerful light.