What is Gamma Correction?
Gamma correction applies a nonlinear relationship between stored signal values and displayed brightness. It accommodates transfer standards, display behavior, and aspects of human visual perception.
How Gamma Correction works
Digital imaging uses transfer functions to map between scene- or display-linear light and compact signal values. Although the process is often described with a power curve, common color spaces may use piecewise functions and distinct encoding and display transforms. Filtering or compositing encoded values directly treats those nonlinear numbers as if they represented proportional light. A color-managed workflow therefore decodes to an appropriate working space, performs light-dependent operations, then applies the output transfer function.
Key facts
- The sRGB transfer function includes a linear segment near black and a nonlinear segment elsewhere, so treating it as one simple power law is only an approximation.
- Alpha compositing and image resampling produce physically more plausible luminance when color channels are linearized first; applying the same math to encoded values often darkens transitions.
- Missing or incorrect color-profile and transfer metadata can cause no correction, double correction, or the wrong curve. Pixel values alone do not identify their intended light relationship.
When Gamma Correction matters
Image pipelines must identify the applicable transfer function before resizing, blending, or converting colors. Treating gamma-encoded values as linear can produce dark blends and incorrect luminance.