title: Optical methods for measuring the pearlescent effect in toiletries.
abstract: Synopsis Pearling agents used to improve the appearance of toiletries are generally judged visually, as it is difficult to devise suitable quantitative tests. If a pearling agent is added to a stirred liquid, moving light and dark patches may be seen. A method has been developed to put this simple test on a quantitative basis. The reflected light is measured using a fibre optic probe. An on-line computer calculates the ratio of the standard deviation to the mean of the intensity; this is a measure of the pearlescent effect. By combining such measurements with turbidity data, a two-parameter description of the appearance of the product is obtained. The method may be used for quality control, comparison of commercial formulations or to monitor changes during storage.
authors.affiliation: Hoechst AG, Postfach 80 03 20, D-6230 Frankfurt a.M., West Germany.
authors.forename: D J
authors.initials: DJ
authors.lastname: Miller
authors.forename: A K
authors.initials: AK
authors.lastname: Reng
authors.forename: W
authors.initials: W
authors.lastname: Skrypzak