Abstract: A pigmentary particulate material selected from the group consisting of titanium dioxide, doped titanium dioxide, and a mixture of titanium dioxide and doped titanium dioxide. The pigmentary particulate material has a mean crystal size of from 0.3 to 0.5 microns, a crystal size distribution such that ?40 wt.-% of the pigmentary particulate material has a crystal size of from 0.3 to 0.5 microns, and a ratio of a mean particle size to the mean crystal size of ?1.25.

Abstract: The present invention provides titania particles which are formed by providing a titania sol and spray drying the titania sol. A morphology of the dried titania particles is controlled by producing the titania sol from a TiO2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania by adding a peptizing agent to reduce an extent to which the titania sol is flocculated, or by producing the titania sol from a TiO2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry by adding a dispersant to reduce an extent to which the titania sol is flocculated. The titania particles have a continuous exterior convex surface, a diameter of 30 ?m or less, a BET specific surface area of 50 m2/g or more, and are porous.

Abstract: A pigmentary particulate material selected from the group consisting of titanium dioxide, doped titanium dioxide, and a mixture of titanium dioxide and doped titanium dioxide. The pigmentary particulate material has a mean crystal size of from 0.3 to 0.5 microns, a crystal size distribution such that ?40 wt.-% of the pigmentary particulate material has a crystal size of from 0.3 to 0.5 microns, and a ratio of a mean particle size to the mean crystal size of ?1.25.

Abstract: The present invention provides titania particles which are formed by providing a titania sol and spray drying the titania sol. A morphology of the dried titania particles is controlled by producing the titania sol from a TiO2 containing slurry and controlling the pH of the slurry to be 3 pH units or more from the iso-electric point of the titania by adding a peptizing agent to reduce an extent to which the titania sol is flocculated, or by producing the titania sol from a TiO2 containing slurry and adjusting the iso-electric point to be 3 pH units or more from the pH of the slurry by adding a dispersant to reduce an extent to which the titania sol is flocculated. The titania particles have a continuous exterior convex surface, a diameter of 30 ?m or less, a BET specific surface area of 50 m2/g or more, and are porous.

Abstract: The invention provides a process for the production of titania particles with a desired morphology. The process comprises providing a titania sol and then drying the sol to provide dried titania particles. The process is characterized in that the morphology of the dried titania particles is controlled by applying one or more of the following criteria: (a) the titania sol is produced from a TiO2 containing slurry obtained using a precipitation step in a sulphate process, wherein the size of micelles formed during the precipitation is controlled; (b) the titania sol is produced from a TiO2 containing slurry and the pH of the slurry is controlled in order to affect the extent to which the titania sol is flocculated; (c) the titania sol is produced from a TiO2 containing slurry and the iso-electric point of the titania is adjusted in order to affect the extent to which the titania sol is flocculated; (d) the titania sol is dried by application of heat and the temperature used during the drying step is controlled.

Abstract: The invention provides a process for the production of titania particles with a desired morphology. The process comprises providing a titania sol and then drying the sol to provide dried titania particles. The process is characterised in that the morphology of the dried titania particles is controlled by applying one or more of the following criteria: (a) the titania sol is produced from a TiO2 containing slurry obtained using a precipitation step in a sulphate process, wherein the size of micelles formed during the precipitation is controlled; (b) the titania sol is produced from a TiO2 containing slurry and the pH of the slurry is controlled in order to affect the extent to which the titania sol is flocculated; (c) the titania sol is produced from a TiO2 containing slurry and the iso-electric point of the titania is adjusted in order to affect the extent to which the titania sol is flocculated; (d) the titania sol is dried by application of heat and the temperature used during the drying step is controlled.

Abstract: The invention provides a method of characterizing a scattering colored pigment for use in the determination of the absorption and scattering coefficients of the scattering colored pigment, the method comprising the step of obtaining a reflectance spectrum of a mixture of the scattering colored pigment with a substantially non-absorbing scattering pigment at a plurality of different volume fractions wherein the substantially non-absorbing scattering pigment has a particle size greater than 0.6 micron. Also provided is a pigment characterization system adapted to perform the method of the invention to characterize a scattering colored pigment.

Abstract: The invention provides a method of characterising a scattering coloured pigment for use in the determination of the absorption and scattering coefficients of the scattering coloured pigment, the method comprising the step of obtaining a reflectance spectrum of a mixture of the scattering coloured pigment with a substantially non-absorbing scattering pigment at a plurality of different volume fractions wherein the substantially non-absorbing scattering pigment has a particle size greater than 0.6 micron. Also provided is a pigment characterisation system adapted to perform the method of the invention to characterise a scattering coloured pigment.