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Tone Sampler and Info

Use the Tone Sampler to read the tones of your photograph. It never changes the picture and adds nothing to the undo history.

Read a tone

  1. Choose the Tone Sampler from the toolbar, or press I.
  2. Move the pointer over the photograph. A small black label follows it, and the Info panel shows the same reading.

A reading has these parts:

  • R, G and B: the red, green and blue of the pixel under the pointer, from 0 to 255. On a black and white picture they are equal. With a Toning layer they differ, so you can see the colour you have added.
  • Grey and its percentage: how light the pixel is, from 0 (black) to 255 (white), and as a percentage.
  • Zone: the tone as a darkroom printer would name it, from 0 (black) through V (a middle tone) to X (white). Zones are estimates of the lightness you see, not exposure measurements.

The values are in the app's working space (a grey with a gamma of 2.2), the same numbers an 8-bit grey export would hold. They include every visible layer, so they change as you edit.

Place sample points

Click the photograph to place a numbered point, up to ten. Each point stays on its pixel and its reading is listed in Info, beside the pointer reading, so you can compare tones in different parts of the picture while you edit. The readings update as you adjust layers.

  • Drag a point to move it.
  • Drag a point off the picture to remove it, or Alt-click it (Option on a Mac), or click the × beside it in Info.
  • The bin button in Info removes every point.

Points belong to the open picture. They are not saved in the project, but they stay in place when you rotate, flip, straighten or crop.

Sample size

Sample in Info sets how many pixels each reading averages: Point reads one pixel, and the others average a square of pixels, from 3 × 3 up to 101 × 101. Use a larger average to ignore grain or dust when you judge a tone. A point keeps the size it was placed with; changing Sample affects the pointer and new points.