Gelatine Dry Plates
The first successful use of gelatine silver bromide emulsion was by Richard Leach Maddox in 1871.1 He described not a complete, finished, process but the results of experiments that provided a basis for others to work from. Further work was undertaken by others over the next few years:2
- J. Burgess (1873) placed ready made emulsion on the market without disclosing his formula. An alkaline developer was used.
- Joshua King (1873) recommended removing the soluble salts from the emulsion.3
- J. Johnston (1873) recommended the emulsion have an excess of bromide.
- W.B. Bennett (1873) published a process where the gelatine was gradually added to the emulsion.
- Richard Kennett (1873) published a formula for a washed emulsion (to remove the soluble salts) that could be stored for later use. He patented the process of drying the emulsion, called a pellicle, which could then be stored and later revived with water. The pellicles were sold by Kennett from about this time, later, pre-coated plates were also sold.4
- Peter Mawdsley of The Liverpool Dry Plate Co. sold pre-sensitised plates in 1874.
- Joseph W. Swan (1877) discovered that heating the emulsion for a long period (ripening) increased their sensitivity, though details were not announced.5
- Charles Bennett (1878) published details of his ripening process which resulted in much more sensitive plates.
The adoption of gelatine dry plates is curious, following Maddox's announcement there was a flurry of activity until the end of 1874. Then very little happened until around 1878 when interest and usage increased dramatically, by 1880 gelatine dry plates had all but replaced the old collodion processes. They were by that time faster than wet-plates, easy to handle and reasonably consistent in quality.
By 1879 the list of gelatine dry plate manufacturers included Wratten & Wainwright, Samuel Fry, Liverpool Dry Plate Co. (Bennett plates) and Mawson & Swan.
An early amateur user was the Rev. H.J. Palmer of Liverpool who published a letter in the Photographic News saying he had used the process to photograph the inside of Beverley cathedral.7
References & Notes
BJA 1880, p. 23. Provides a summary and history of the process. Eder, History, p. 421. Gernsheim, History, p. 327.
[1] The BJA 1903, p. 681 carries an extensive obituary of Maddox (1816 - 1902) written by his daughter.
[2] Gelatine had been proposed as a carrier for silver salts before this time but nothing came of the ideas. For a description of earlier work see W. Jerome Harrison's History of Photography (1888) or BJA 1880, p. 23.
W.H. Harrison published an article in 1868 on his partly successful experiments with gelatine silver bromide.
[3] BJP 12/6/1874, p. 277. BJP 19/6/1874, p. 294.
[4] BJP 19/6/1874, p. 291, article by Kennett on the use of his gelatino-bromide process. Phot. News 1/1/1875, p. 6.
BP 3782/1873. It was wrongly thought at the time that Kennett was attempting to patent the complete process rather than just the pellicle.
Kennett's formula: heat 1 lb of gelatine in 100 oz. of water until dissolved, mix in 8.25 oz. of potassium bromide, add 11.25 oz. of silver nitrate and mix. Pour the emulsion into a dish and allow to set. The emulsion is then cut into strips and washed to remove the free potassium bromide and nitrate of potash. Once dried the emulsion can be stored. To use, dissolve the pellicle in hot water.
[5] Phot. Journal 12/1928, p. 509.
[6] BJP 1877, p. 86.
[7] Phot. News 9/4/1875, p. 178. The exposure was 1' 10" taken in December.