A general scum that forms on non-image areas of the printing plate and is transferred to the paper. Originally believed to be caused by contaminants from coated paper, it is now known that tinting is more a function of plate desensitization, various ink formulations, fountain solution problems, and other aspects of press chemistry, in particular the emulsification of the ink by the fountain solution. In particular, tinting occurs when particles of ink pigment bleed into the fountain solution, and are transferred to the non-image areas of the plate, printing as a colored tint. The tendency for tinting to increase with increasing temperature has resulted in its also being known as hot-weather scumming. Tinting is rarely a problem anymore. Tinting is also known as washing, and in waterless printing is known as toning.
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