Cobalt siccative, oil paints accelerator drying. Cobalt siccative one of the best siccative for art painting. It’s very concentrated as it contains 1.5% cobalt. It is added for faster drying. For 1 liter of pure linseed oil add 5 ml of this siccative. The amount of 100 ml is therefore sufficient for 20 liters of linseed oil. In normal use, it is added drop by drop. A larger addition is not beneficial, but detrimental in that the top coat dries very quickly, forming a hard film, and then the paint dries through all layer with difficulties.