Ben Day shading mediums, for art work on stone, metal & card board;
A trade manual issued by Ben Day, Inc. in New York in 1920, explaining the Ben Day shading-medium apparatus to commercial artists, engravers and lithographers. Line diagrams show gloved hands pressing inked screen films onto stone and card, plus exploded plan views of the holdfast, carriages and lever clamps, useful as period technical drawing, hand gestures, and printshop hardware.
