Alternative processes

Cyanotype

Cyanotype is one of the easier alternative processes, made by a mix of iron compounds.
To make a cyanotype, Potassium ferricyanide and Ferric ammonium citrate are used and mixed seperately with water. Then both substances are mixed together equally. Whatever absorbent material is being used is covered with the mixture and needs to be air dried in the dark. Then the objest or photo being used is placed on the material covered in mixture, and is put under a UV lamp or in the sun. Once the photo is at desired exposure, rinse in water and let dry. This creates a blue background with a white print of the negative or object.

Daguerrotype

 Each daguerreotype is a detailed, photo on a polished, silver-plated sheet of copper, sensitized with iodine vapors, exposed in a large box camera, developed in mercury fumes, and stabilized with salt water. Through this long and intricate process, Iodine fumes react with silver causing a color shift in the plate.

Gum Bichromate

A mixture of gum arabic, a dichromate, and pigment is mixed together and spread on a canvas. The negative is placed on top of the canvas and put under the sun or a UV lamp. A sheet of glass is put over the negative in order to ensure that the negative is constantly touching the mixture on the canvas. Finally the canvas is put in a series of water baths and dried. This process creates vivid colors in the image.



http://www.metmuseum.org/toah/hd/dagu/hd_dagu.htm
http://www.alternativephotography.com/wp/processes/daguerrotypes/becquerel-daguerreotype
http://www.alternativephotography.com/wp/processes/gum-bichromates/an-introduction-to-the-gum-bichromate-process