Abstract: A process for preparing a pigment based on bismuth vanadate by reacting an acidic solution of bismuth nitrate with a basic solution of ammonium metavanadate to form a precipitate in a very acidic reaction mixture with a pH value of between 1 and 2. The pH of the reaction mixture is brought to a value of about 7, and the temperature of the reaction mixture is established at 80.degree. C. or higher for a period of about 30 minutes. The reaction mixture is stirred for a period of time of at least one half hour until a pH of approximately 6.5 is reached, and then the precipitate is filtered from the reaction mixture. Finally, the precipitate is washed and dried to obtain a dried pigment.

Abstract: The invention relates to an organic pigment, preferably an azoic pigment, characterized in that it has been treated with polyalkylene imine with a view to improving its characteristics when used in painting. This treatment can be carried out both on an organic pigment treated by known methods and on an untreated pigment. A treated pigment is generally preferred, however, particularly if maximum opacity is desired.

Abstract: A bismuth vanadate based yellow inorganic pigment is disclosed together with a process for making bismuth based yellow inorganic pigments.