Photography history – Before images were recorded
People have wanted to record images since pre-history. It was not until the 11th Century that the pin-hole image projection was invented. Light was allowed through a pinhole into a blacked-out tent. This projected an upside down image on the tent wall. The method was called the ‘Camera Obscura’. However, there was no way to record an image. People used the projection as a template for painting.
Many famous names appear in photography history. Francis Bacon described the camera obscura. He said it was a way of safely observing eclipses of the sun in the 13th Century. Leonardo da Vinci (1452–1519 AD) described the camera obscura too. Despite an early beginning, it was not until later that image making involved lenses. The use of lenses and mirrors were added to the camera obscura in the 17th Century. This made a portable device that projected an image the right way up. The “camera” was still unable to record an image. It was however an important part of photography history.
The earliest image in photography history
The first known recorded image was taken in 1825. Joseph Niépce (1765–1833; later called Nicéphore Niépce) experimented with ways to expose chemicals to capture images. Most images quickly faded. The first successful photograph was taken using bitumen dissolved in lavender oil. The chemicals were coated onto a pewter plate. The exposure too eight hours in a camera obscura. The plate was washed in lavender oil to remove the unexposed bitumen. This left a a thin layer of hardened bitumen making the image.
The Daguerreotype image
Niépce experimented with other ways to record images. The most successful method involved working with Louis Daguerre. After Niépce died in 1833 Daguerre continued the work and developed the Daguerreotype process. The Dagurreotype process used a copper plate. It was coated with silver and held in iodine vapours. The plate was exposed to the light source which created a positive ‘latent image’. This was ‘fixed’ to the plate by bathing in salt water. Exposures varied according to the chemical mixes and purity, but could be more than 15 minutes.
Later development lead to improved images and fixing. Daguerreotype images proved popular. But, the search was on for improved methods of image capture. Unfortunately, the Daguerreotype created a positive image. It could not be reproduced. More on Daguerreotype (Wikipedia) . It was, despite that, an big step forward in photography history terms.
Chemicals in photography history – Emulsions
Emulsion plates, followed the Daguerreotype images. During the 1840s various emulsion processes were invented. Emulsions react faster, some needing only two or three seconds exposure. A gel-like substance was coated on a tin or glass plate which was then exposed to create an image as a deposit. The unexposed gel was washed off and the remaining deposit was then ‘fixed’ leaving the final image. However, the chemicals in the gels varied and there were various processes. Popularity of photos drove the industry forward. It also left legacy systems. The important processes of the time included…
• The Calotype process (by Fox Talbot by 1840). A silver chloride emulsion produced a negative image.
• An Albumen emulsion invented by Niépce St. Victor (cousin of Joseph Niépce)
• Frederick Scott Archer. Invented the “Collodion” process (1851) with silver halide chemicals in gelatine.
The first emulsion processes needed wet plate processing within 15 minutes of exposure. Photos had to be developed on location. It was a problem for many types of photography.
As emulsions developed so did the equipment. Count Sergei Lvovich Levitsky made a bellows camera in 1847. This improved camera focusing. The camera could be folded. This made it more portable. Bellows are used in some modern cameras and lens systems. It’s a classic system which has stood the test of time. Lenses improved too. Astronomers, notably William Herschel, worked with lenses for many years. Photography benefited from the work too. In 1839 John Herschel (son of William Herschel) invented the glass negative. From it a number of reproductions could be made. This was not possible with the positive image. Reproducing an image was a big step forward in making photos useful. It changed photography history.
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By Damon Guy see his profile on Google+.