Technical analysis of several paintings by Jan van Goyen and Salomon van Ruysdael indicates that the characteristic appearance of the Dutch tonal landscapes cannot be ascribed only to physical alterations with age. The appearance of the support through the paint and the limited tonality are deliberated aesthetic effects achieved by the artists' choice and use of their materials. The use of low refractive index, thinly applied grounds and paint, bone black, ground glass and limited palettes suggest the effect the artist intended.