How to Use Curves in Photoshop

Curves in Photoshop: Adjustment Layer, Not Adjustment

Image > Adjustments > Curves bakes the change into the current layer permanently. Layer > New Adjustment Layer > Curves – or the half-dark circle icon at the bottom of the Layers panel – creates a separate, re-editable Curves layer with a mask attached. Always take the adjustment layer route.

Reading the Curves Graph

Darks sit on the left of the Curves graph, lights on the right, with the histogram behind the line showing where your image’s information actually lives. Drag the bottom-left point to the right and everything left of it goes pure black. Drag the top-right point left and everything right of it goes pure white. Drag those same points vertically instead and your blacks become gray or your whites become gray – the matte, faded look.

Making a Curve in Photoshop

Click anywhere on the Curves in Photoshop line to add a point, then drag it up to brighten that part of the tonal range or down to darken it. Add a point in the highlights and one in the shadows and pull them in opposite directions and you have the classic S-curve for contrast. You can add as many points as you want – though a fancy curve is not automatically a better photo. Most real-world edits are a single point in the middle nudged slightly up or down.

Color by Channel with Curves in Photoshop

The Curves in Photoshop channel menu defaults to RGB, which is exposure. Switch it and each channel works between complements: on Red, up adds red and down adds cyan; on Green, up adds green and down adds magenta; on Blue, up adds blue and down adds yellow. Move the endpoints rather than the middle and you tint only the shadows or only the highlights – blue in the shadows with yellow in the highlights is a cross-process look built in about ten seconds.

Hand, Eyedroppers and the Pencil

The Curves hand icon lets you click on any area of the photo and drag up or down; Photoshop finds that brightness value on the curve and moves it for you. The three eyedroppers set black point, gray point and white point by clicking – the gray one only helps when there is a genuinely neutral area to click on. The pencil icon lets you draw a curve freehand, which is fun and almost never useful.

Presets

Curves in Photoshop ships with presets like Increase Contrast, Cross Process and Color Negative. Build a look you like, then use the panel menu and Save Curves Preset to keep it – it loads into the preset dropdown on every future Curves layer.

Masking Curves in Photoshop

This is how Curves in Photoshop gets used most. Brighten the image with a curve, then select the layer mask and Edit > Fill with black to hide the effect completely. Now paint with white using a large soft brush over just your subject’s face – the brightening appears only where you painted. Dodging and burning specific areas this way, rather than lifting the whole frame, is the heart of most retouching work.

Curves in Photoshop Quick Reference

• Ctrl/Cmd + M – Curves (or Layer > New Adjustment Layer > Curves)
• Click the line to add a point; drag up to brighten, down to darken
• Channel complements: Red/Cyan, Green/Magenta, Blue/Yellow
• Edit > Fill with black on the mask, then paint white to target an area
• Panel menu > Save Curves Preset – reuse a look