Tone curves for photographers: S-curves and faded blacks

For photographers who reach for the curve and aren't sure why. Checked against CullTone on 20 Oct 2026.

The tone curve is the one panel that can do the work of five sliders, and the one most people use by feel. Read it like a map and it gets simple: the bottom edge is the brightness going in, the left edge is the brightness coming out, and the diagonal means nothing changed.

Above the diagonal, that tone gets brighter. Below it, darker. Steeper than the diagonal, more contrast in that range of tones; flatter, less. That is all of it.

The S-curve, and the orange skin it brings

An S-curve is the classic contrast move: pull a point in the shadows down, push a point in the highlights up. It looks crisp on a landscape. On a portrait it has a side effect that catches a lot of people out. Applied to red, green and blue together, more contrast also means more saturation, so skin gets more orange as the curve gets steeper. If faces go warm and loud after a contrast edit, the curve did it, not the white balance.

Two fixes: make the S gentler, or apply contrast to brightness only, which many editors offer as a luminance curve or a separate contrast slider. Then check the faces (skin tones).

Faded blacks and held whites

Lift the bottom end of the curve off the floor and nothing in the picture is fully black. That is the faded, matte finish of a lot of film-inspired editing. It suits a garden wedding in soft light. On a dark reception it can look like fog, because most of that frame lives in the very tones you just greyed out.

Pull the top end down a touch and nothing is fully white either. A small amount of that saves the lace on a white gown and the clouds in a bright sky; a lot of it makes the whole set look like it was printed on newsprint.

Several of the 54 looks are built on these shapes. Fine-art film and Matte pastel use faded blacks and soft whites, Low-key dramatic uses a firm S with deep shadows, High-key bright lifts exposure and shadows while holding the highlights, and Vintage fade lifts its blacks and warms them (all the looks). Each one has a strength slider, so you set how much of the curve a wedding gets.

Curves for each colour

Most editors also let you curve red, green and blue separately. This is where split toning comes from. Raise blue in the shadows and they turn cool; lower blue in the highlights and they turn warm. A little gives a cinematic separation. Overdone, every shadow in the set goes teal, including the ones on people's necks.

Three mistakes worth unlearning

• Copying a curve between scenes. A curve that suits a sunny ceremony will crush a candlelit dinner. Curves belong to light, not to a wedding.
• Points everywhere. Two or three points do almost everything. Seven points usually means the exposure was wrong to begin with.
• Fixing exposure with the curve. Set exposure first, then shape. A curve can't recover highlights the exposure already clipped.

Our position, which some editors will dispute: most finished wedding sets need less curve than they get. If you can see the curve when you look at the photo, it's too much.