From what little we know of the studio procedures of artists, it seems that, as elsewhere in Europe, the face was probably drawn and perhaps painted at an initial sitting or two. The typical number of further sittings is unclear - between zero (for a Rembrandt full-length) and 50 appear documented. The clothes were left at the studio and might well be painted by assistants, or a brought-in specialist master, although, or because, they were regarded as a very important part of the painting. Married and never-married women can be distinguished by their dress, highlighting how few single women were painted, except in family groups. As elsewhere, the accuracy of the clothes shown is variable - striped and patterned clothes were worn, but artists rarely show them, understandably avoiding the extra work. Lace and ruff collars were unavoidable, and presented a formidable challenge to painters intent on realism. Rembrandt evolved a more effective way of painting patterned lace, laying in broad white stokes, and then painting lightly in black to show the pattern. Another way of doing this was to paint in white over a black layer, and scratch off the white with the end of the brush to show the pattern.