In metallography*, offset* and in the preparation of zinc or aluminium plates according to lithographic methods, the solution of gum arabic used does not penetrate the plates but is nervertheless strongly attached to the plate. This type of adhesion is called adsorption and is a partially unexplained phenomenon which may be opposed to that of absorption encountered in lithographic work on stone surfaces. [ *lithography]
The gathering of molecules of a particular kind at the interface between two phases such as the pigment and vehicle in printing inks. Adsorption can effectively remove a component such as the drier from an ink vehicle. It is not a chemical reaction and the binding force is a loose one.
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