1. History of Photography II From Calotype to Film

2. Evolution cont. • Daguerre’s and Niepce’s work was publicy announced at the Academie des Sciences in 1839 • Caused immediate public interest in the images • French painter Paul Delaroche declared “from this time on, painting is dead!”

3. Calotype • Following on the announcement of Daguerre, an englishman, William Henry Fox Talbot, announced his research to the Royal Society and the Royal Institution in England • He developed a process known as “Photogenic Drawing” • Used paper sensitized with silver chloride. Would expose in a camera and fix with a salt water bath. Talbot then contact printed the paper negative to a sensitized paper to form a positive print. Exposure times decreased. • Detail not as great as daguerreotype • Calotype process used to create first book of photography “The Pencil of Nature” 1844

4. William Henry Fox TalbotThe Open DoorPlate VI, "The Pencil of Nature"c. 1844

5. Fixing the Image • John Hershel invented a true method for fixing images • Used sodium thiosulfate, which he mistakenly called sodium hyposulfate. • Called it hypo and the term stuck to today! • Salt water fixatives became a thing of the past • Hershel coined terms photography, negative and postive

6. Collodion Wet-Plate Process • People wanted the ease of the negative to positive process, but with clarity and depth of detail found in daguerreotypes. • Experimented with coating glass plates with silver halide, using egg whites (albumen) as a carrier • Glass plates not as sensitive • Tried same process with paper and had better results. • Billions of eggs used in the late 19th century

7. Collodion cont. • Frederick Scott Archer used collodion as transparent adherent • Collodion = dissolved gun cotton in ether and alcohol which dries clear and tough • Mixed collodion with potassium iodide and coated on glass plate • Plate sensitized by dipping in silver nitrate, which created silver iodide • Drawback= plates had to be exposed and processed before collodion dried or development chemicals would not penetrate • Incredible results, could create many prints from plates….by 1850’s, daguerreotypes a thing of the past

9. Dry plate process • Gelatin became important adherent/carrier for silver salts. • Richard Maddox discovered in 1871 • Others perfected process by 1879 • Allowed for development at a later time and allowed for mass production

10. There’s More! • Glass plates still in use, but heavy and fragile • Search went on for a flexible, light and durable base • George Eastman invented a flexible base • First roll film! • However, base not transparent, so emulsion had to be stripped from base and processed at manufacturing plant. • Eastmen developed a returnable camera and promoted the slogan “You Push the Button, We Do the Rest!” • Modern day photography and mass appeal is born!