Color printing digital printing methods do not have the restriction of a single color space that traditional CMYK processes do. Many presses can print from files that were ripped with images using either RGB or CMYK modes. The color reproduction abilities of a particular color space can vary; the process of obtaining accurate colors within a color model is called color matching. Inks used in color printing presses are semi-transparent and can be printed on top of each other to produce different hues. For example, green results from printing yellow and cyan inks on top of each other. However, a printing press
Conservation and restoration of photographs Additive Color Model Applied physician James Clerk Maxwell made the first color photo by mixing red, green, and blue light. 1871: Gelatin dry plate Richard L. Maddox discovered that gelatin could be a carrier for silver salts. By 1879, the gelatin dry plate had replaced the collodion wet plate. It was a revolutionary innovation in photography since it needed less light exposure, was usable when dry, meaning photographers no longer needed to pack and carry dangerous liquids, and could be standardized because it could be factory produced. 1873: Platinum Printing (Platinotype) William Willis patented platinum printing in Britain. The process