the potential generated by the contact of two dissimilar materials in air or in a vacuum.
noun, Photography. 1. a photographic print made by placing a negative directly in contact with sensitized paper, with their emulsion surfaces facing, and exposing them to light. noun 1. a photographic print made by exposing the printing paper through a negative placed directly onto it
noun 1. an apparatus used for making contact prints, having a frame for holding printing paper and negatives together and a light source for making an exposure.
noun 1. the process of making contact prints.
noun, Chemistry. 1. a catalytic method for producing sulfuric acid from sulfur dioxide and oxygen.