Low key-of reduced intensity; restrained; understated.having chiefly dark tones, usually with little tonal contrast .
Dictionary.com
-When something is less vibrantĀ or grasping
high key-having chiefly light tones, usually with little tonal contrast.
Dictionary.com
-Making something pop over the other tones in the project.
texture density-It also involves groups of objects appearing denser as they move farther away. Also could be explained by noticing a certain amount of detail depending on how close something is, giving a sense of depth perception.
wikipedia
– 
the way something looks more detailed then another objective giving it a sense of space in relation to its focus.
gouache-a method of painting using opaque pigments ground in water and thickened with a gluelike substance
– changing the texture of the paint to make it look darker and thicker.
Tonal progression-is a succession of color mixtures proceeding from dark to light. In addition to value change
Theryderstudio.com
-The more color you add changing it to different lightness or darkness.
shade- a color, especially with regard to how light or dark it is or as distinguished from one nearly like it.
Google.com
-How light or dark something is
tint- Ā various lighter or darker shades of a color.
Merriam-webster.com
-how the shades look lighter or darker
tone- in an artistic context refers to the light and dark values used to render a realistic object, or to create an abstract composition.
wikipedia
-how lightness and darkness make art realistic.Ā
venn diagram-uses circles to represent sets, in which the relations between the sets are indicated by the arrangement of the circles.
Dictionary.com
– The way colors over lap when they combine
