The principles of design are the fundamental parts of an artwork. Identifying these principals is one way to understand an artwork.
#5 - VALUE
Value in art refers to the lightness and darkness of color and is often described in varying levels of contrast.
A value scale shows the range of tones from white, which is the lightest, to black which is the darkest. The closer together the values are on a scale, the less contract we see.
Artists utilize a range of techniques to show value, including use of line and intensity of color.
Henry Ossawa Tanner, Artist The Banjo Lesson, 1893