Which characteristic describes the intensity of a color in the Munsell Color Appearance System?

In the Munsell Color Appearance System, brightness is indeed the characteristic that describes the intensity of a color. Brightness refers to how light or dark a color appears, essentially measuring the amount of light that is reflected from a surface. It allows us to distinguish between colors that may have the same hue but differ in their lightness or darkness.

In this system, colors are categorized based on three dimensions: hue, value, and chroma. Hue indicates the type of color (like red or blue), value refers to the lightness or darkness of the color, and chroma describes the purity or saturation of the color. While saturation can also relate to the vividness of a color, it does so in terms of the amount of gray present in the color, rather than its overall brightness. Thus, when specifically discussing intensity in relation to how brightly a color is perceived, brightness is the most accurate term in this context.