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No other pigment poses as many problems for the user as carbon black (C.B.). These problems are related to the exceptionally small particle size and the complex adsorption layers on its external and internal surfaces. C.B.'s range in size from 70 milli‐microns down to 10 millimicrons.

During film formation, many physical factors play a roll, namely: temperature, composition and speed of evaporation of the solvent, viscosity, surface tension, specific gravity and solubility of the resin in the solvent. At the point of application of a paint film, all these factors are equally balanced. Upon disturbance of this equilibrium, the liquid seeks a new equilibrium by which surface defects may occur.

With the increasing industrial usage of epoxy coating materials, Ault and Wiborg have published a leaflet covering the systems and substrates applicable to their Peridite solvent‐free epoxy coatings. The leaflet describes the properties and applications, and explains the various methods of use.

The pace of technical development in the paint industry is seemingly nowhere more rapid than in the field of raw materials, with almost every issue of paint journals containing reports of new products and details of their practical application. In truth many of these new materials are comprised of nothing more radical than standard products with slight changes in some minor detail, but at the other end of the spectrum are those materials which are so novel that whole new avenues of research are opened up. Wherever any new product is placed on the broad spectrum of novelty however, there is no doubting that many new opportunities are constantly being created for paint chemists to utilise. This series of articles will consider some of the literature that has appeared in the technical press in the last three years, and will cover recent developments in the technology of pigments and extenders, convertible and non‐convertible media, as well as solvents and additives. It is hoped that these reviews will enable paint chemists to take full advantage not only of the new products which have recently appeared on the market, but also heighten their awareness of new approaches to formulating with established raw materials. This first article is concerned with colouring pigments which here have been split into two broad categories of white and spectral colours. Later articles will consider developments in anti‐corrosive pigments and extenders.