Titanium dioxide treated with polymeric hindered amine stabilisers

A pigment forming material comprising particulate titanium dioxide and wherein the particles have been treated with a polymeric stabilizer with hindered amine. The stabilizer is a polymer with a main chain substantially free of acid groups and with stabilizing groups of hindered amine. The stabilizing groups comprise at least 35% by weight of the polymer. The titanium dioxide particles are preferably also treated with an organic compound such as a polyhydric alcohol, an alkanolamine, a polysiloxane or a fatty acid.