TAPPI UM 658:2015 provides laboratory procedures for comparing the color strength and shade of paper dyes against a selected standard dye. It covers soluble dyes used for calender staining and surface coloring, soluble and insoluble colorants used in beater applications, and pigment evaluation.
The document includes two methods: Method A for surface-coloring dyes and Method B for beater dyeing. It outlines required apparatus, reagents, sample preparation, dyeing procedures, handsheet formation and drying, visual evaluation under daylight or a standard daylight lamp, reporting requirements, and guidance on shade differences. The method indicates that comparative color strength can generally be estimated within 5% when carefully applied.
Application Scope: For paper mills, dye and pigment manufacturers, laboratories, and quality-control personnel evaluating comparative color strength and shade in paper-coloring applications.
