Luma measures the brightness (luminance) of an image, independent of its color (chroma). It defines how light or dark pixels appear, usually measured in IRE or levels from 0 (black) to 100 (white). It’s what you’d see if the image were in black and white.
Luma is fundamental to exposure and broadcast safety. It affects contrast, dynamic range, and exposure. It’s essential for tonal correction, especially when adjusting highlights, shadows, or black levels.
Use luma controls when balancing contrast, fixing over/underexposure, or matching brightness across shots. Too high and highlights blow out; too low and shadows crush into black. Luma scopes (like waveform monitors) help analyze it accurately.
Check with scopes – Use waveform monitors to assess luma levels accurately.
Protect highlights and shadows – Avoid crushing blacks or blowing out whites by balancing luminance.
Use selectively in effects – Apply luma masks for transitions, keying, or compositing for creative precision.