Warnerke Standard - Antique and Vintage Cameras

Warnerke Standard

1880

Marion & Co. Ltd

London

England

Image of Warnerke Standard

Consists of a printing frame, density plate with 25 squares of varying density, phosphorescent tablet and holders for magnesium ribbon. Quarter-plate size.

Notes:
Address on box: Marion & Co. 22 & 23 Soho Square.

With:
Box with Marion label.

This is the earliest commercial sensitometer preceding the work of Hurter and Driffield. The standard light source is a phosphorescent tablet that has been exposed to burning magnesium ribbon. The plate to be measured is placed behind the graduated density plate in the printing frame and exposed for a fixed time to the phosphorescent tablet. The rapidity of the plate can be gauged by seeing which of the graduated squares is visible. This instrument was widely used and several manufacturers labelled their plates with Warnerke numbers. The value measured was the threshold value of the plate. Each Warnerke number represented a 1/3 increase in speed over the previous. The price was 15/-.

References & Notes:
Marion's Guide to Photography, p. 261. Eder, History, p. 450. Abney, Instruction, p. 141.


Company Details:

Marion

Sensitometry

Warnerke Standard

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