GELATIN DRY PLATE

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Survey of Negative Processes Glass-Based Processes

Contents

[edit] historical background

steps of evolution:

  • forerunner: experiments with gelatin plates by Alphons Poitevin not successful

(EDER, JOSEF MARIA, 1932, p 473)

  • 1868 experiments by W.H. Harrison with gelatin dry plates: barely used

(GERNSHEIM, HELMUT, 1983)

  • 1871 publication by Dr. R.L. Maddox (plates are comparably insensitive, due to acidly prepared emulsion and a high excess of silver)

(NATIONAL MUSEUM OF PHOTOGRAPHY, FILM AND TELEVISION, 2000; TAFT, ROBERT, 1964, p 365 et seqq.)

  • 1873 first publication of a really successful process by Johnson

(NADEAU, LUIS, 2006, p 72)

  • 1873 first ready-made silver bromide emulsion by John M. Burgess in trade, with which plates could be self coated: not successful

(EDER, JOSEF MARIA, 1930, p 5; NORRIS, DEBBIE HESS, 1989b; NADEAU, LUIS, 2006, p 89)

  • 1874 washed gelatin emulsion as pellicles introduced by Richard Kennett: has to be solved in water before use, during solution due to the effect of heat the emulsion got incidentally ripened and thus the sensitivity got increased

(EDER, JOSEF MARIA, 1930, p 5; COE, BRIAN, 1986, p 39; GERNSHEIM, HELMUT, 1983, p 397 et seqq.)

  • 1877 improvement of sensitivity by Sir John Swan (heating of the emulsion), consequential develops the ripening process by Charles Bennett: addition of ammonium hydroxide, let it rest or warming up to 40°C for a week, or up to 100°C for 30 minutes (ripening by warming or alkalis leads to extension of the silver bromide grains)

(NORRIS, DEBBIE HESS, 1989b; GILLET et al., 1986; EDER, JOSEF MARIA, 1930, p 100)

  • 1878 first industrially made plates in trade (London, Wratten & Wainright and Liverpool Dry Plate Company) , from 1879 on also in Germany

(EDER, JOSEF MARIA, 1930, p 14; HANSCH, MARTIN, 1985, p 64)

  • in the beginning plates were only sensitive to blue light, from 1873 on orthochromatic plates exists which are also sensitive to yellow and green light (e.g. eosin-plates by Hermann Wilhelm Vogel: tinting of the silver salts by aniline dyes), 1874 also sensitive to red-orange, since 1899 panchromatic plates available (silver salts are tinted with isocyanides): color separation possible

(GERNSHEIM, HELMUT, 1983, p 403 et seq.; JAHR, 1930; HANSCH, MARTIN, 1985, p 64)

  • intensive use of gelatin dry plates from approximately 1880 on

(McCABE, CONSTANCE, 1991; EDER, JOSEF MARIA, 1930, p 14; TAFT, ROBERT, 1964, p 365 et seqq)

  • used up to the 1970ies
  • general process: photographic emulsion is prepared (including sensitization) then poured on the glass plate; this is an important difference to the former processes since there the light sensitive salts develop not until the plate is coated

(TAFT, ROBERT, 1964, p 365 et seqq.)

[edit] properties

advantages over the wet collodion process: easier to handle, long maintenance, increased light sensitivity and contrast (especially with the ripening process): for the first time snap-shot photography possible

(McCABE, CONSTANCE, 1991)

difference between gelatin and collodion plates:

  • gelatin generates an emulsion with the silver salts which are uniformly dispersed, due to hygroscopy of the gelatin the processing chemicals can deeply permeate into the emulsion
  • gelatin creates a protection layer around the silver grains which makes them softer and bigger enlargements possible
  • in collodion plates the image develops on the surface whereby in gelatin plates the image develops within the emulsion

(GERNSHEIM, HELMUT, 1983, p 402 et seq.)

gelatin gelatin is made of bones, skin, tissue and ligaments, depending on the composition it can have an impact on the sensitivity of silver salts.

(GERNSHEIM, HELMUT, 1983, p 402 et seq.)

[edit] process

publication by Maddox from 1871:

  • formula with aqua regia (hydrochloric acid and nitric acid), potassium bromide and silver nitrate *development with pyrogallic acid and silver nitrate
  • exposure time 30 seconds to 1,5 minutes
  • disadvantage: decomposition of the emulsion in very high temperatures

(GERNSHEIM, HELMUT, 1983)

during the 1870ies hand-coated plates possible, after that mainly industrially made

(McCABE, CONSTANCE, 1991)

[edit] preparation

  • cleaning and polishing of the glass
  • impregnation with sodium silicate

(GILLET et al., 1986)

  • substratum: dipping of the glass plate into a solution of 0,5 to 1% gelatin and chrome alum, substratum can also be made of collodion or albumen, alternatively etching of the glass surface

(GILLET et al., 1986; McCABE, CONSTANCE, 1991; ADELSTEIN et al., 1977)

[edit] sensitization

light sensitive salts (e.g. silver bromide by precipitation of silver nitrate and potassium bromide or ammonium bromide) in a solution of gelatin

(GILLET et al., 1986)

[edit] development

first developers for gelatin plates:

  • ferrous oxalate
  • pyrogallic acid

(TAFT, ROBERT, 1964, p 371)

  • later on also hydroquinone (since 1880, intensive developer)
  • pyrocatechol
  • hydramine (hydroquinone + para-diphenylamine)
  • derivatives of phenol, metol or glycine

(GILLET et al., 1986)

[edit] hardening

solution of potassium alum or chrome alum

(GILLET et al., 1986)

[edit] fixing

exclusively sodium thiosulfate

(GILLET et al., 1986)

[edit] post treatment

[edit] coating
  • protection varnish possible (formulas like with collodion plates) or collodion varnish

(GILLET et al., 1986; PEDERSEN et al., 2005)

  • after 1890ies rarely protection varnishes (after that gelatin plates only varnished if designated for printing with printing-out paper since silver from the paper can result in stains in the negative emulsion)

(McCABE, CONSTANCE, 1991; PEDERSEN et al., 2005)

  • 1888: recommendation for coatings of sandarac on gelatin dry plates: enables pencil retouching

(DAFFNER, LEE ANN, 2003)

[edit] retouching
  • retouching by grating and scratching (knife, abrasion by a powder)
  • with panchromatic plates less corrections or coatings necessary since the production of negatives is so much easier that one single plate is not that valuable anymore

(PEDERSEN et al., 2005)

  • coating combined with retouching by scratching for attenuation (e.g. gelatin coating makes the fringes of scratches softer by slight swelling)

(PEDERSEN et al., 2005)

[edit] chemical post treatment

GILLET et al., 1986

intensification with

  • mercuric ammonium chloride
  • mercuric iodide
  • copper bromide

reduction with

  • potassium cyanide
  • copper salts
  • thiosulfates
  • potassium ferricyanide
  • permanganate

[edit] industrial production

[edit] preparation

  • treatment of the glass with a diluted solution of sodium silicate or coating with an substratum made of chrome alum hardened gelatin

(EDER, JOSEF MARIA, 1930, p 30 et seq.)

  • anti-halation by :
  1. double layer (very insensitive emulsion between glass and high sensitive emulsion): in use for only a short period
  2. tinted back-coating
  3. tinted layer between glass and emulsion

(JAHR, 1930; EDER, JOSEF MARIA, 1930, p 34)


[edit] References

  • ADELSTEIN et al., 1977. Adelstein, P.Z.; Gray, G.G.; Burnham, J.M.. Manufacture and physical properties of film, paper and plates. In: John M. Sturge ed. Neblette's Handbook of Photography and Reprography. Materials, Processes and Systems. New York: Van Nostrand Reinhold Company, 127-147
  • COE, BRIAN, 1986. Das erste Jahrhundert der Photographie 1800-1900. Bindlach: Gondrom
  • DAFFNER, LEE ANN, 2003. "A Transparent Atmosphere": The Paper Negatives of Frédéric Flachéron in the Harrison D. Horblit Collection. JAIC, 42 (3), 425-439
  • EDER, JOSEF MARIA, 1930. Ausführliches Handbuch der Photographie. Band 3, Teil 1. 6. Auflage. Halle a.S.: Knapp
  • EDER, JOSEF MARIA, 1932. Ausführliches Handbuch der Photographie. Band 1, Teil 1. 4. Auflage. Halle a.S.: Knapp
  • GERNSHEIM, HELMUT, 1983. Geschichte der Photographie: Die ersten 100 Jahre. Frankfurt/ Main: Ullstein
  • GILLET et al., 1986. Gillet, Martine; Garnier, Chantal; Flieder, Francoise. Glass Plate Negatives. Preservation and Restoration. Restaurator, 7(2), 49-80
  • HANSCH, MARTIN, 1985. Frühe Photographien - ihre Technik und Restaurierung. Überherrn/Saar: Kabinett-Verlag Uwe Scheid
  • JAHR, 1930. Jahr, R.. Die Fabrikation der photographischen Trockenplatten. In: Alfred Hay ed. Handbuch der wissenschaftlichen und angewandten Photographie, Vol. IV. Wien: Julius Springer. 214-247
  • McCABE, CONSTANCE, 1991. Glass Plate Negatives: The Importance of Relative Humidity in Storage. In: Sauvegarde et Conservation des Photographies, Dessins, Imprimés et Manuscrits. Actes des Journées Internationales d´Études de l´Arsag, 30 sept.-4 oct. 1991, Paris. Paris: Association pour la Recherche Scientifique sur les Arts Graphiques, 36-44
  • NADEAU, LUIS, 2006. Encyclopedia of Printing, Photographic and Photomechanical Processes (1st eBook ed., V.1.1.). Fredericton, NB (Canada)
  • NATIONAL MUSEUM OF PHOTOGRAPHY, FILM AND TELEVISION, 2000. Photography on Glass. Bradford: National Museum of Photography, Film and Television (Information Sheet 5.3.21)
  • NORRIS, DEBBIE HESS, 1989b. Gelatin Dry Plate Negative. University of Delaware
  • PEDERSEN et al., 2005. Pedersen, Karen Brynjolf; Kejser, Ulla Bøgvad; Johnsen, Jesper Stub; Christensen, Mads Chr.. Coatings on Black-and-white Glass Plates and Early Film. In: Constance McCabe ed. Coatings on Photographs. Washington D.C.: AIC. 108-131
  • TAFT, ROBERT, 1964. Photography and the American Scene: A Social History, 1839-1889. New York: Dover (Reprint)


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