22 ago. 2008

A (Very) Brief History of Photography (Part 1)

“And God said, Let there be light: and there was light.”
And light was used by all: to frighten and to encourage, to blind and to lead, to destroy, and to create. And light was used to write…
The word photography comes from the Greek words phos (light) and graphis (brush). And that’s exactly what photography is all about: Drawing with light.
Photography is a complex art, being the result of a series of technical discoveries from several different disciplines. Photography involves math, physics and chemistry.

The first “photographic” device known to humanity is the Camara Obscura. Although the Camara Obscura had already been around for a while, it was Ibn al-Haytham, an Arab philosopher, who described it thoroughly in his Book of Optics (circa 1000 a.D). It was simply a box, with a tiny hole in it. The hole would let a small portion of light into the box, and strike a specific part of the back wall, usually a piece of paper, on which the artist would copy the image. As the hole got smaller, the image also became sharper, but more light would be needed (depth of field).

Then, Silver Nitrate and Silver Chloride were discovered in the 12th and 16th century, respectively. Silver Nitrate is the precursor to other silver salts, and Silver Chloride is the “magical” substance from which photographic film is made, since it turns from white to metallic- black/gray via photoreduction. Finally, in the mid-1820’s, Nicéphore Niépce, a French inventor, created the first “photograph”, and 8-hour exposition from a window in Le Gras. He named this new process “Heliographie” or “drawing with the sun”.

Shortly afterward, the term Photographie was used by Hercules Florence, a French artist, to name a process similar to Niépce’s. Meanwhile, William Fox Talbot, an English inventor, had discovered yet another process to create images from a silver salt-based process. Upon reading about Niépce’s invention, Talbot made some adjustments to his process to take faster expositions to be able to photograph people. John Herschel, another English inventor refined Talbot’s negative image process (called calotype) and created the cyanotype, or blueprints. He discovered sodium thiosulphate solution to be a solvent of silver halides in 1819, and informed Talbot of his discovery in 1839 that it could be used to make pictures permanent.

In 1851, an article, written by Frederick Scott Archer, appeared on “The Chemist”. The article reported Scott’s findings on the Collodion wet plate process. Collodion is a nitrocellulose solution in ether, which happens to be also toxic and extremely flammable (another name applied to Nitrocellulose is the word “Guncotton”, because it can be used as a projectile driver, with 6 times the gas generation of black powder (in his book From the Earth to the Moon, Jules Verne’s mega cannon Columbiad uses guncotton to propel a cylindroconical projectile to the Moon)). The discovery of the Collodion process disposed of the albumen process on glass plates, and made the time of exposure shorter. The new process required the projection surface (glass) to be cleaned extremely well. Then, the glass would be flowed with salted Collodion, after which, the glass would be immersed in a silver nitrate solution for about 5 minutes. The plate was then ready to be exposed, and the developed in an iron-based developer. The plate was then fixed with the exposure, and varnished with a mixture of gum sandarac, alcohol and lavender. This process had to be done within minutes of each other, which meant a photographer carried the chemicals wherever he went. It is quite extraordinary there are no reports of a photographer dying in a guncotton related explosion, or from silver nitrate-related poisoning.

Then, in the late 1880’s, the dry collodion plate was introduced to replace the wet plate. By 1884, the film process was created, but it was years before it was adopted as the standard exposure process.