Levels remaps tones with input and output black and white points and a gamma control. It has four independent sets of the same five controls: Master, Red, Green, Blue and Alpha.
How to use it
- Select a layer and choose Effects ▸ Levels.
- With Channel on Master, set Input Black and Input White to stretch the tonal range, and Gamma for midtones.
- Switch Channel to Red, Green, Blue or Alpha to adjust one channel.
All sets always apply (per-channel first, then Master). Switching Channel only changes what you are editing, not the picture.
Parameters
Each channel has these five:
| Name | What it does | Default / range |
|---|---|---|
| Channel | Which set is shown: Master, Red, Green, Blue, Alpha. | Master |
| Input Black | Input value that becomes black. | 0, 0–1 |
| Input White | Input value that becomes white. | 1, 0–1 |
| Gamma | Midtone curve. Above 1 brightens midtones. | 1, 0.1–10 |
| Output Black | Darkest output value. | 0, 0–1 |
| Output White | Brightest output value. | 1, 0–1 |
The panel also shows a levels graph for the effect.