The quality and depth of a colour that has been mixed with either white or black, which affects the way it reflects light. To help with a common misconception: the tone refers to the depth of a colour, and the hue to its essence, i.e. whether it is red, green, yellow…Black and white don’t affect the hue, but are essential for changing the tone of a colour.
Tone is also a term used to describe the character and atmosphere of a space.