Tonal value refers to the lightness or darkness of a color or an object. It helps create depth and contrast in a painting or photograph. Full definition
Also, Minimalists like Ad Reinhardt's Abstract Painting no. 4 (1961) with it's varying tonal values of black — along with the earlier work of Russian constructivists like Kazimir Malevich, and his The Black Square (1915). (artthrob.co.za)
Color field painting is defined by expanses of color close in tonal value and intensity, large presentations and simple compositions. (theeagleonline.com)
Learning to paint with tonal values creates depth, realism, and dynamic beauty in our art. (arttutor.com)