Test mixture for impregnating sample cloths used in testing the graying effects of washing liquids or powders over time comprises between 0.1 and 30 percent of black or black-coloring pigments

摘要

Test mixture containing dirt and or impurities comprises 0.1-30% of black or black-coloring pigments. The pigments include rust, graphite and/or iron oxide. The mixture further contains 20-80% alumina.