The idea of stenciling canvases with the trademark of the shop selling artists' materials, originated in London in the late 1790's. By the 1830's, New York City adopted the English idea; a decade later other large American cities followed suit, such as Philadelphia and Boston. Stencils can often be used as a means of dating paintings when they do not contain any other identifying marks, as frequently the stencil bears the address of the preparator. These individuals, perhaps due to the vagaries of the business, frequently moved, so that one is assured in these instances that the fabric was prepared within a short span of time. The business directories of large cities are a convenient source of information on these art supply retailers. By carefully recording all of these individuals and the dates when they were at a specific location, as has been done for Boston, one can fix the dates of stencils that are discovered. Other data, such as the positioning of the stencil and the color of ink used, are important criteria which may reflect the idiosyncracies of the preparator. This information, in quantity, may be of use in dating unaddressed stencils. -- AATA