Översaturation

Översaturation, or supersaturation, is a state in which a solution contains more dissolved material than the equilibrium solubility at a given temperature and pressure. The condition is typically metastable: the excess solute is unsustainable in the long term and the system tends toward equilibrium through crystallization or precipitation when disturbed.

The formation of an oversaturated solution can occur by cooling a saturated solution slowly, by evaporating solvent, or by changing the solvent or temperature in other ways. Crystallization is often triggered by a nucleation event, such as the introduction of a seed crystal or a small disturbance, after which the excess solute gradually precipitates out.

Oversaturation is utilized in various fields. In chemistry and materials science, supersaturated solutions are used in recrystallization and controlled precipitation to obtain purer or differently structured crystals. In geology and mineralogy, supersaturation in aqueous systems can lead to mineral deposition as conditions change during transport or evaporation. In meteorology and atmospheric science, brief vapor supersaturation can occur and promote condensation, contributing to cloud or fog formation when nucleation sites are present.

In imaging and digital media, översaturation refers to color channels that exceed the maximum representable value, a condition known as clipping. This can produce unnatural colors and a loss of detail in the affected areas. Oversaturation can be intentional in some photographic effects but is often undesirable in accurate color reproduction.

Overall, översaturation describes a transient, non-equilibrium state in which more dissolved material or signal content exists than the system can stably hold, prompting a return to equilibrium through crystallization, condensation, or clipping effects.