Abstract: A system for introducing flowable additive e.g. colorant from a syringe into paint varnish, woodstain or the like contained in a closed container provided with an inlet into the container which inlet is closed by a closure. The inlet is openable by insertion of the nozzle of the syringe into the inlet which thereby ensures that the nozzle of the syringe is correctly located in the inlet before expulsion of the additive commences.

Abstract: Measurement of the color properties of wet paint, such as lightness by colorimetry or photospectrometry, is carried out on a sample volume contained in a vessel and while the sample volume is subjected to shearing forces and advantageously also turbulence. The shearing and turbulence are created by a rotating disc having a spiral rib configuration on one surface which faces a window through which the measurements are made by a spectrophotometer.

Abstract: Surface coating films containing metallic flake pigment are characterized by (a) illuminating the film with a parallel beam of light which is inclined at a given angle to the film normal and (b) measuring the intensity of light reflected from a point on the film at a plurality of azimuthal viewing positions located in a circle which lies in a plane parallel to the film and through the center of which passes the film normal at the point. Apparatus suitable for carrying out the measurements is described. The invention enables the frequency distribution of the orientations of the metallic flake in the film to be determined.