Wooden box with opal glass at one end; backed by perforated plate with holes of different sizes, box internally divided into squre compartments. Glass plate, 1/2 plate size with number sequence painted on in squares; 7, 8, 10, 11, 14, 16, 20, 23, 28, 32, 39, 45, 56, 64, 78, 90, 111, 128, 156. With manuscript instructions. Spurge sensitometer
Sensitometer. Used at Harrow. Rotating sector wheel; filter box with flap shutter; light source missing. Sensitometer
Electric motor-drive; metal sector disc approx 260mm diameter; flap shutter; no light source. Disc sensitometer
Darkslide containing step wedge with 21 steps. Phosphorescent plate made luminous by burning magnesium and placed in holder. Plated exposed through wedge under luminous plate for 30 seconds. No.79. L.Warnerke. Warnerke's Standard Sensitometer
Box containing Chapman Jones plate tester in darkslides. Exposure board with candle holder (folding candle shade missing) and candles. Sanger Shepherd and Co. The Chapman Jones Plate Tester