Curves

Curves are graph-based grading tools: you drag a line to remap one image attribute against another. The plain custom (luma) curve maps input brightness to output brightness, so lifting a point brightens the tones beneath it — and where you grab it matters, because the black end, gamma middle and white end target different tonal ranges. The HSL curves — hue-vs curves (hue-vs-hue, hue-vs-sat, hue-vs-lum) and the lum-vs-sat curve — instead let you isolate one hue or one brightness zone and adjust it alone, which biases you toward gentle, artifact-free moves. Because hue runs in a circle, the hue curves wrap around at the edges, just like the vectorscope.

First used in: 2.5 · The curves family