144. Chapman Jones Plate Tester, c. 1901
Signed: 'Fraction Tint / Actinometer / Sanger Shepherd & Co.' [and address].
The speed of the photographic plate was determined by the last number of this plate tester visible after exposure (and printing). Sanger Shepherd supplied the material for colour photography by the three-colour separation method (Items 102 to 105 and 147).
Height 107 mm, width 82 mm.
Inventory no. 58,605.