Drawing Techniques: a Guide
Dry Media: Brown, Yellow, Blue Chalk, etc.  
Ochres, yellows, browns and other natural colored chalks were available by the sixteenth century. Early in the century Milanese artists like Bernardo Luini, following Leonardo's example, were using them for flesh tones and for details. Jacopo Bassano and Federico Barocci of Urbino developed a sophisticated technique of combining them, blurring the contours by rubbing the chalk with the finger or a leather stump. By the eighteenth century French artists had formalized the medium for highly finished portraits which duplicated in their own way the effect of finished oils. At the same time manufacturers began to produce artifical chals, which superseded natural chalks within a generation or two.


Combined Chalks
Fabricated Chalks