Van Dyke Brown Prints
A brown print and its younger sister, kallitype, can be made on paper, leather, or fabric and can yield permanent images rich in detail, with subtle separations in the middle tones and shadows, ranging from pale to deep Van Dyke brown. A photographic negative, when placed in contact with the silver-based emulsion, produces a positive picture after relatively short exposure to daylight or ultraviolet light. The longer the exposure, the darker the brown of the print. A brown print also reacts positively to such toners as polytoner, selenium, sepia, copper, and blue (see Chapter 3, Toning) to produce purples, pinks, and blues. Brown printing, which is costlier than cyanotype, due to the price of silver nitrate, one of its component chemicals, can be combined with some other techniques described in this book and with traditional artists’ materials such as paint and pastels.