Build a value scale from your own reference, read off the grey and hex of every step, and download it to keep beside the easel.
A printed grey scale runs in even steps from black to white. Almost no subject does. An overcast landscape may live entirely between 30 and 70 percent, and holding an even scale against it tells you very little.
The scale below comes out of the photograph you load. It shows the steps that are actually present, how far apart they sit, and what each one is in hex. That is the information you need at the moment of mixing, and it changes with every reference.
Five is enough for most work and forces real decisions. Nine matches the traditional teaching scale. Raise it only when five genuinely cannot describe what you are looking at.
The number on each step is its brightness on the 0 to 255 scale, not the share of the picture it covers. A step at 27 percent is a dark mid-tone whether it fills a corner or half the canvas.
The download button on the scale gives you a PNG with the step number, brightness and hex printed on each swatch. Print it, or keep it open on a second screen; either way you stop guessing halfway through.
Values are easy to misjudge and hard to describe. A hex code is neither: it pins a step down exactly, so you can sample it in a digital painting, check a mix against the screen, or write it in the margin of a study and still know what you meant a week later.
If you want to compare two areas rather than list them, the pipette in the tool names the difference between any two points in words.
A value scale taken from your own photograph rather than a generic printed strip. The tool reads the image, divides it into as many steps as you ask for, and gives you the grey and the hex of each one. You can then download the scale as a PNG and keep it beside the easel.
A shop-bought scale is evenly spaced from black to white. Your subject is not. A scale built from the image tells you which values are actually in front of you and how far apart they sit, which is the information you need when mixing.
Nine is the traditional teaching scale and five is enough for most alla prima work. Fewer steps force harder decisions, which is usually the point. Start at five, raise it only when five genuinely cannot describe what you are looking at.
Brightness on the 0 to 255 scale, where 0 is black and 100 percent is white. They are not the share of the picture that value covers. A step reading 27 percent is a dark mid-tone regardless of how much of the canvas it fills.
Mixing and matching. It lets you sample the same value in a digital painting, check a mix against the screen, or note down where a step sits without describing it in words.
No. The scale is computed in your browser and the download is generated on your own device. The image never leaves your computer.