Original text - Engels - imprimatura

The degree of darkness or lightness of imprimatura should be chosen in relation to the largest light area of the future painting, such as a white drape or a face.
You can use only yellow ochre and lamp black. However, Prussian blue and burnt umber are added to accelerate drying of the next layers.
The presence of Prussian blue and burnt umber in imprimatura enables you to make your mixture warmer or colder.