Cobalt is an extremely active & most widely used drier in coatings & capable of being used even as a single Drier. It is primarily an oxidation catalyst & acts as a "Surface Drier ". It may have a tendency to cause surface wrinkling, hence to provide uniform drying. Cobalt is generally used in combination with other metals, such as Manganese, Zirconium, Calcium and Combinations of these metals.

As quantity of Cobalt Drier used is very small, it minimizes discoloration in paints & enamels as compared with other Driers. Cobalt does not discolor white paints as the deep blue color of the cobalt counteracts the yellow of the oils & resins & thereby enhances the optical brightness of the paint. The unique feature of cobalt is that it is least affected by atmospheric humidity. Cobalt is an effective accelerator for polyester.