A Short History of Photographic Processes - up to 1900 by Mike Ware Buxton U3A February 2014 Photo by Mark Osterman

Alhazen’s Camera Obscura ca AD

Camera Obscura with Lens ~1550

The Raw Materials of Proto-photography Sunlight Silver chloride (Angelo Sala 1612)

The “Gernsheim Question” (Photohistorians Helmut and Alison Gernsheim) 1000 Camera obscura known with pinhole 1512 (Girolamo Cardano) with lens 1610 Silver chloride darkening in sunlight 1839 Announcement of photography “Why was photography not invented long before the early 19 th century?”

Tom Wedgwood ( ) Contact-printed images on silver nitrate coated on paper and white leather ca Unfixed – none survive? No camera images made Published with H. Davy Royal Institution 1802

Joseph Nicéphore Niépce ( ) Bitumen of Judaea coated on a pewter plate is hardened by light-exposure. Rendered insoluble in oil of cloves. Exposure many hours Ca

Niépce’s Heliographic Process The “First Photograph” 1826 Niepceotype

William Henry Fox Talbot ( ) Inventor of silver halide photography on paper (1834) Chief contributions: Sensitized by excess Ag + Fixed by excess halide Negative-positive process Collection of National Media Museum RPS Collection

Talbot’s “First Negative” on paper

Talbot ’ s Working Method “ Photogenic Drawing Paper ” 1)Immerse writing paper in ~1% salt for 2 minutes 2)Blot dry 3)Brush over with 20% silver nitrate (a 6x excess): AgNO 3 + NaCl  AgCl  + NaNO 3 4)Expose for ~10 minutes in sunlight to darken UV + AgCl(s)  Ag(s) + Cl 2 (g) ↑ 5)Fix with ~30% salt or ~2% potassium iodide

Photogenic Drawings by Talbot ca 1839 Thiosulphate fixed? Chloride fixed?

Iodide fixed Photogenic Drawing WHF Talbot “ Agrostis Gigantea ” On verso: “ H.F. Talbot Photogr ” Paper is J. Whatman Turkey Mill 1838 National Media Museum UK

Sir John F. W. Herschel ( ) Invented ‘ Hypo ’ fixation in Based on chemical experiments of 1819 with ‘ hyposulphites’ (now thiosulphates) which dissolve silver chloride. Still used in ‘fixer’ today. Portrait, Royal Society 1843

Thiosulphate-fixed Salt Print WHF Talbot “ Melrose Abbey ” National Media Museum UK

Proto-photography “ Prints-out ” Sun supplies all the energy of image formation Exposure by direct solar irradiation ~1 minute AgCl(s) + UV  Ag(s) + 1 / 2 Cl 2 (g) ↑ For contact prints: Photogenic Drawings Prints from engravings and camera negatives Exposures in the camera are very lengthy – lens only captures 1/100 to 1/1000 of the light

Camera Exposure Factors Given only proto-photographic materials: contact exposures take about 1 minute camera exposures (at f/4) take 1-2 hours (at f/11) 10 hours Camera photography is nearly impossible A marginal technology, at best, as Talbot & Daguerre found independently - until they separately discovered different ways of: Development of latent images in silver iodide

Louis Jacques Mandé Daguerre ( ) Daguerreotype Silvered metal plate Iodized with I 2 vapour to Give coat of silver iodide. Exposed in the camera for a few minutes. Latent Image in the AgI developed with Mercury vapour – Ag/Hg amalgam Ca Published 1839

Talbot ’ s “ Waterloo ” Paper Annotated “ w ” : uses silver bromide sensitizer

Photographic Development Talbot in 1840 discovered that gallic acid can “ bring out an invisible dormant picture ” impressed on silver iodide by very little light The developer supplies the chemical energy His camera exposure times reduced by 100x An extraordinary fluke - not predictable Photography was practice-led: No theory of latent image until the mid-C20 th

Gallic acid Developer 3,4,5-trihydroxybenzoic acid C 6 H 2 (OH) 3 COOH Oak Galls

Chemistry of Talbot ’ s Calotype 1) Iodize: AgNO 3 + KI  AgI  + KNO 3 silver nitrate + potassium iodide  silver iodide + potassium nitrate 2) Excite: Talbot ’ s “ Gallo-nitrate of silver ” AgNO 3 + acetic acid + gallic acid 3) Expose: Moist or dry ~1 f/15 4) Develop: “ Gallo-nitrate of silver ” reduces Ag + + e -  Ag  silver cation + electron  silver atom 5) Fix: KBr (or hot strong thiosulphate) Ag + + Br -  AgBr  silver cation + bromide anion  silver bromide 6) Wax: Less refractive index difference

The “ Black Art ” of Development “ Surely you deal with the Naughty One ” Sir John F.W. Herschel (16th March 1841) William Henry Fox Talbot

Outline of Silver Development Silver halide microscopic crystals suspended in a photographic “ emulsion ” - a colloidal binder A small amount of image light striking any crystal sensitizes it - forming a ‘ latent image ’ - an invisible cluster of ~10 atoms of silver Developers chemically reduce the sensitized crystals of AgX entirely to grains of Ag metal A Crystal may contain 10,000,000 AgI, so amplification is 1,000,000 & Exposure becomes ~ 1 hour ÷ 1,000,000 = 1/300 second

Albumen Print of Buxton UK

Cartoon from ‘ Punch ’ 1847 Behold thy portrait - day by day, I ’ ve seen its features die; First the moustachios go away, Then off the whiskers fly…

Processes for Camera Negatives ProcessInventorDateHalideSurfaceBinderDeveloper Photogenic Drawing Talbot1834AgClpapernoneNone Print-out Daguerreo- type Daguerre1837AgImetalnoneHg vapour CalotypeTalbot1840AgIpapernonegallic acid + AgNO 3 AlbumenNiépce de Saint Victor 1847AgIglassalbumengallic acid + AgNO 3 Wet Collodion Scott Archer 1851AgIglasscellulose nitrate pyrogallol or Fe 2+ + AgNO 3 Gelatin Dry Plate Maddox1871AgBrglassgelatinPyrogallol (alkaline)

Relative Exposure Times ProcessASA speed Projection  (f/number) 2 Contact Modern film Modern paper Gelatin dry plate Wet collodion Calotype Daguerreotype ,00010 Photogenic drawing Proto-photography ,000,00010,000

Chromium-based Printing 1839 Mungo Ponton ( ) Paper coated with a soluble dichromate is light-sensitive. Chromium(VI) is reduced and hardens organic colloids – gelatin, gum etc Pigments may be bound in to form a photograph. Carbon & gum processes.

Iron-based Printing 1842 Sir John F.W. Herschel Ferric salts of ‘vegetable acids’ – e.g. citric, oxalic, tartaric, are light-sensitive and form ferrous salts. The photoproduct can reduce salts of noble metals (silver, gold, platinum) to an image in the metal. Ferrous can couple with ferricyanide – Prussian blue

Photochemistry of Iron(III) Salts e.g. Citrate, Oxalate, Tartrate UV Light Fe(III) Salt –> Fe(II) salt ‘ ferric ’ ‘ ferrous ’ The Fe(II) photoproduct can:- 1. Precipitate a noble metal from its solution 2. Couple with ferricyanide –> Prussian blue 3. Leave Fe(III) to form inks with gallic acid

Historical Iron-based Processes 1842 Herschel Cyanotype Prussian blue 1842 Herschel Argentotype Silver 1842 Herschel Chrysotype Gold 1842 Herschel Celaenotype Mercury 1861 Colas Ferrogallate Iron-gall ink 1873 Willis Platinotype Platinum 1889 Nicol Kallitype Silver 1916 Willis Palladiotype Palladium

Characteristics of Siderotypes [Iron-Based Printing Processes]  Aqueous sensitizer – no colloidal binder  Plain paper – matte surface texture  No ‘ amplification ’ – contact printing only  Large format negative required  Sensitive only to UV and blue light  Archival permanence with Pt, Pd, and Au

Chemicals for Cyanotype

Cyanotype from an Engraving

Anna Atkins ( ) Botanical illustrator Sun-printed sea-weeds in Herschel’s cyanotype to make the first book which was illustrated photographically.

Anna Atkins - British Algae

An Aesthetic Blueprint !

“ Made in Scotland from Girders ”

Scotland’s other National Beverage! Contains 0.002% Ammonium Ferric Citrate

New York Subway - Brooklyn

Prussian blue in art & science

William Willis jr Used sensitivity to light of ferric oxalate to make prints in platinum metal. The most stable and most beautiful photographs ever seen

Commercial Platinotype ca. 1900

“ The Artists go on boldly, and are not afraid to be Chemists, the Chemists gain courage and long to be Artists. ” The Athenaeum, 1858