Non-linear tonal curve defining the relationship between input signal and displayed brightness.
Definition
Gamma describes the non-linear relationship between electrical signal and luminance. Historically determined by CRT tube characteristics, today mathematically defined for color space standards.
Application in Practice
Standard gamma 2.2-2.4 for displays. Log gamma for acquisition (maximizes dynamic range). PQ (Perceptual Quantizer) for HDR. The correct gamma setting is essential for proper contrast.
Technical Details
Mathematically: Output = Input^γ. Rec.709 uses gamma ~2.4 with toe adjustment. sRGB has a more complex curve with a linear segment. Log curves (Log-C, S-Log) use a logarithmic function instead of a power function.
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