Abstract: An automated computer-controlled method and apparatus for measuring the quality or fineness of a pigment dispersion sample, comprising placing the pigment dispersion at the deep end of the tapered path of a Hegman gage block, placing the Hegman gage block in a holder in a motorized drawdown device that draws the scraper along the length of the tapered path at an angle and to at a contact pressure and at a controlled rate, thereby creating a tapered film sample of paint whose thickness tapers from a maximum thickness of 100 micrometers to a minimum thickness of zero. An illuminator assembly illuminates the sample with a substantially collimated light source at an intensity level and the light reflected from the sample is collected by a lens onto a photodetector array in a digital camera. After a time interval the camera acquires an image of the sample.

Abstract: The present invention relates to a process for making a titanium dioxide pigment having consisting of titanium dioxide and single layer of inorganic surface treatment consisting of aluminum phosphate wherein the pigment is characterized by and isoelectric point which is greater than pH 6 and a negative zeta potential of at a pH of 7.5 or more.