The wet collodion process

- [voiceover] In 1851 the Englishman Frederick Scott Archer invented the wet collodion process of making negatives. This process allowed photographers to produce finely detailed images on paper and to print an unlimited number of copies. These key features were improvements over the previous two photograph processes, the daguerreotype and the calotype. From 1851 until about 1880 the wet collodion process became the dominate method for making photographs throughout Europe and North America. Producing a wet collodion image had to be done quickly and efficiently. This is because collodion, the main chemical used, will dry up and lose its sensitivity after about 10 minutes. Photographers used portable darkrooms, so the plate could be developed immediately after it was shot. The wet collodion process can be broken down into a number of equally critical steps. First the edges of the glass plate are smoothed with a sharpening stone to help the collodion adhere better to the plate. The glass is polished with a solvent, such as rotten stone or glass wax. Next the glass is carefully cleaned again to remove any dust particles. This is important because any remaining particles will show up as dark spots on the final image. A mixture of iodides, bromides, ether, and alcohol are added to the collodion to help make it photosensitive. The solution is then allowed to age for (mumbling) a week prior to use. Using a method called flowing the plate, the collodion is poured carefully onto the center of the glass. The collodion enables the silver nitrate to adhere to the plate, so it is crucial that the collodion covers the entire surface. Inside the darkroom the photographer dips the plate into a bath containing silver nitrate, the chemical that will make the plate sensitive to light. The plate is left in the bath for about three to five minutes. The photographer then removes the sensitized plate from the silver bath and lays it inside the plate holder. The collodion side is placed face down so that it can receive the path of light once inside the camera. Any excess silver nitrate is removed from the back. Once closed the plate holder emits no light, which allows it to be safely removed from the darkroom. in the back of the camera the photographer makes final adjustments to the composition to the image before inserting the plate holder. He must make any changes now, for once the holder is in place it is no longer possible to focus the camera. The plate is exposed to light by first pulling the dark slide out and then removing the lens cap to expose the plate for the required amount of time. The lens cap is then placed over the lens and the dark slide inserted back in the plate holder. Once closed, the plate holder is removed from the camera and brought back into the darkroom. In the darkroom the glass plate is removed from the plate holder. Developer is then poured onto the plate. It is important that the developer is poured in an even, sweeping motion, otherwise it will leave ridges and markings on the final image. When the photographer is satisfied with the image, water is poured over the plate to stop the development. The exposed and developed plate is placed in a bath of fixer to permanently preserve the image. The plate is left in the fixer until it clears. After removal the plate is washed thoroughly in water. After the plate is dry it has to be varnished to protest the fragile image surface from damage. The plate is heated to facilitate this process. A clear coat of varnish is applied to the plate, much as the collodion was. This must be done very carefully, since the varnish can accidentally dissolve the image. Once the plate is varnished a print can safely be made from it. Photographers most commonly printed wet collodion negatives on albumen paper. This is made by first floating a sheet of photographic paper on a solution made from egg whites, then floating it in a tray of silver nitrate. After drying, the paper is placed in contact with the negative in a printing frame. The negative is then exposed to sunlight and the image emerges during the exposure. The photographer watches it carefully to determine when to arrest exposure. The finished print is called an albumen print. Colors range from reddish to purplish-brown and the prints have a lush, glossy surface. Albumen prints made from wet collodion negatives remained extremely popular until about 1880 when they were replaced by more industrialized photographic methods.