Developing - Antique and Vintage Cameras

Developing

Image of Developing

There were several different methods for developing negatives:

Inspection
This was the earliest and was still in use well into the 20th century. The negative was placed in a dish with the developing solution, the photographer judged when development was complete by holding the plate to a safelight. To compensate for wrong exposure or lack of contrast it was normal, at the time, for the constituents of the developer to be altered during development based on how the image was appearing.

Factorial
Introduced in 1893 by Alfred Watkins. It was found by Watkins that the time of initial appearance of the image indicated the speed at which the developer was working and that the complete development time was a simple multiple of the appearance time. The multiple differed for each developer and was known as the Watkins Factor. The type of plate and the temperature affected the appearance time but not the Factor. The photographer could alter the Factor depending on the degree of contrast required.

Stand
Very weak developer was used together with a prolonged development time of several hours. With shortened times this method merged into the Time method. A tank was generally used.

Time
Also called Time & Temperature. In the early 1900s development of plates and especially roll-films started to be standardised based on the type of developer, temperature and the type of plate. The popularity of roll-film, which was difficult to process by inspection, and smaller negative sizes were major factors in this change. The change meant that development could take place in light-tight tanks rather than a dish. With development (and enlarging) now able to take place in daylight, away from the darkroom, this branch of photography was opened up to the beginner and part-time photographer.

Thermo
In the early years of Time development the factors affecting development time (temperature, type of developer and plate type) were understood but not well formulated. Around 1908 Watkins, with his skill of systematising, published tables of plate types classified into their development speeds. A table was then used to give the dilution strength of developer to be used based on plate type and developer. This combination gave a solution that required a fixed time (6 m for dish, 24 m for tank) at 60F to produce a correctly developed plate. For other temperatures the Watkins Time Thermometer or tables supplied with the Watkins Time Developer could be used. The plate classification can be found on the Watkins speed list, plates were grouped into: VVQ, VQ, Q, MQ, MS, S, VS for very very quick, very quick, quick, medium quick, medium slow, slow, very slow. The standard Time Thermometer was calibrated for developers having a Temperature Coefficient of 1.9, for other developers the photographer would need to construct his own scale, a template was provided to do this. Watkins published and patented details on how to construct a calculator with settings for Temperature Coefficient and temperature but this does not seem to have been made commercially. Thermo became obsolete as better information was published by plate manufacturers. The Temperature Coefficient is the rate at which the development time changes with varying temperature, its value is expressed for a 10C temperature change.

Daylight developing tanks, both plate and roll-film, for the Time method appeared in the early 1900s. They were preceded by what might be described as miniature darkrooms that could be operated in daylight, these took the form of an enclosed tray or developing area, a safelight window to inspect the plate and a spout to pour out the liquid.

References & Notes:
Watkins Manual 1911, p, 92. BJA 1909, p. 577. BP 22456/1907 (Thermo). Watkins, Photography. Its Principles and Applications, p. 87. Cyclopedia of Photography, p. 179. Neblette, Principles and Practice, p. 305.

Further Information:
Photographica World no. 127, article by Geoff Preece on developing tanks.

Rocking Dishes

Hanoware

Two, quarter-plate dishes. These are porcelain dishes with a groove in the base, by placing a pencil in the groove the dish is converted to a rocking dish.

Trident Roll-Film Developing Weight

c. 1904

W. Butcher & Sons

London

England

Image of Trident Roll-Film Developing Weight

  • 3 " wide film, with quarter-plate dish.
  • 3 " wide film, with registered design number of 424609 in the inscription.
  • 3 " wide film, with registered design number in red box carrying the Ensign Ltd name, after 1930.
  • 5" wide film, in brown box carrying the Butcher name.

The 3 " size was advertised as the No. 1, the 5" size as the No. 2. Also sold under the Primus brand name.

References & Notes:
BJA 1908, p. 167. Butcher's British Cameras, 1924, p. 110.


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Butcher & Son

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