Abstract: In accordance with the instant invention red transparent iron oxide pigment is prepared from yellow transparent iron oxide pigment filter cake by drying and calcining in a single operation using a spray dryer employing a nozzle of the two fluid design.

Abstract: An apparatus for purifying copper phthalocyanine pigment in a continuous process without the use of acid. This apparatus comprises a container for preparing a slurry of said pigment in water, a pump and a conduit for conducting the slurry from the container to the inlet of the pump, a first heating apparatus capable of heating the slurry to a temperature of at least about 75.degree. C., a conduit for conducting the slurry from the pump to the first heating apparatus, a thin film pressure filter, and a conduit for conducting the slurry from the first heating apparatus to the thin film pressure filter. The apparatus is arranged such that the temperature of the slurry passing through the thin film pressure filter is close to the exit temperature of the slurry from the first heating apparatus. A product outlet is provided for the filter and a control valve is positioned in the product outlet.