In the field of colour theory tone describes the darkness of a colour or hue.
- In the context of additive colour models such as RGB or HSB, a darker tone of a hue is produced by reducing its colour brightness. The result is a desaturated, muted version of the original colour.
- In the context of subtractive colour models such as CMY and RYB, A darker tone (or shade) of a colour is achieved by adding black to it. The result is a desaturated, muted version of the original colour.
- In photography, tone refers to the different shades of grey that can be produced, ranging from pure white to pure black.
- In the context of a greyscale, tone is used to describe the relative darkness or lightness of a specific shade of grey.
- A greyscale is the result of removing hue from a range of colours leaving their saturation and brightness unaffected.
- Whilst yellow appears to have a very light tone when converted to greyscale, blue appears to have a very dark tone.
- Tone is closely related to the term value.
- Value refers to the amount of light reflected from a surface or emitted by a computer screen.
- White has a high value while black has a low value.