Tone: histogram, exposure and clarity
Press ⌃1 for Tone. The panel opens on it the first time; after that it opens on whichever tab you were last in. The histogram at the top tells you where the tones sit, and the sections under it move them. The field above the histogram, Ask for an adjustment…, and the tone curve, the last section of this tab, each have a page of their own: Asking for an adjustment and The tone curve and Levels.
Reading the histogram
The Histogram section is first and is the only section in the panel that reads rather than writes. It owns no setting, never lights the tab's dot and has no reset.
- RGB draws the three channels as translucent fills on one shared scale, so a colour cast shows as channels at different heights. Luma draws one neutral curve. The choice is remembered.
- Under the plot: crushed and blown as percentages of the frame, and mean as a value from 0 to 255. All three are read from the same measurement the curve is drawn from.
- The line beneath always begins Measured on the 2048 px preview, not the file, then says which state the well is in. Normally it names the size, in pixels, the numbers were counted at. While a slider is under your hand it holds the last full render's numbers rather than measuring the half-size draft, and adds Held while you drag — the numbers are the last full render's, not the draft's. A frame that has not finished rendering shows an empty well, a dash in each of the three readouts, and Nothing measured yet — this frame has not finished rendering.
The clipping warnings on the top panel use the same two thresholds, so the overlay and these numbers can never disagree. See Zoom rungs and viewing aids.
Exposure and Contrast
The Exposure section holds the two controls every frame starts with.
| Slider | Range | What it does |
|---|---|---|
| Exposure | −2 to +2 stops, shown as +0.35 EV | Overall brightness, in stops |
| Contrast | −100 to +100 | How far apart the tones are pushed |
Both start at 0. The number beside each slider turns orange once it has moved; double-click a row to put it back to 0.
On a RAW file, Exposure is applied inside the RAW decoder rather than to the finished picture, which recovers highlight detail a rendered image has already thrown away. The slider looks and moves the same, but a subject or background scope does not narrow it. See The RAW stage.
Highlights and Shadows
The High dynamic range section has one slider for each end of the tonal scale.
| Slider | Range | What it does |
|---|---|---|
| Highlights | −100 to +100 | Above 0 brightens the bright tones; below 0 darkens them |
| Shadows | −100 to +100 | Above 0 lifts the dark tones; below 0 deepens them |
Each slider moves the tones about a quarter of the way in from its end of the scale, by up to about 15% of the scale at full throw, and holds pure black and pure white where they are. So Highlights below 0 darkens a bright sky, but a pixel that has already clipped to white stays white; the slider does not bring back what the exposure lost. Shadows is the same at the dark end.
Reach for these before Exposure when only one end of the frame is in trouble: a bright sky over a correctly exposed field wants Highlights down, not the whole frame darker.
Clarity, Texture and Dehaze
The Clarity section holds three sliders, each from −100 to +100 with 0 as no change.
- Clarity pushes local contrast at a broad scale — the midtone punch a landscape or reportage frame often wants. Below 0 it softens instead.
- Texture is the same push at a much finer scale: skin, fabric, stone, without the broader lift Clarity also brings. Below 0 it smooths fine detail.
- Dehaze works out the colour of the haze itself and how much of each part of the frame reached the lens through it, then takes the haze out. Below 0 it lays a veil of that same haze back over the frame.
Both Clarity and Texture work from the frame's brightness alone, so a red jacket pushed harder comes out a more contrasty red, not a different red. Where there is nothing to react to, such as a plain wall, the pixels do not move.
Dehaze reads a large, flat, mid-toned area — a grey wall, a blank overcast sky, a snowfield — as haze, and darkens it. There is nothing in a single photograph to tell the two apart. On such a frame, keep Dehaze low. A mask cannot narrow it to the distance: Dehaze, like Clarity and Texture, applies to the whole frame, and a mask carries only the eight tonal sliders.
This section has an eye: switch it off to see the frame without all three.