The Kinetics of the Dark Reaction in Bichromated Colloids.

The kinetics of the dark reaction in Iithographic coatings have been found to provide a powerful tool for research. The path of the dark reaction can be described with good accuracy by the mathematical expression for a first order reaction. The specific reaction rate is found to be a function of the two variables, temperature and relative humidity. Utilizing a mathematical expression employing empirical data it has been possible to predict with relative ease the shelf life of a number of different coatings. The paper introduces the concept of half life into lithographic terminology and is concerned largely with the classical derivation and practical verification of the first order chemical equation.