Method of colouring or tinting paper

Abstract From the Canadian patent

The colouring or tinting of paper is achieved during the paper making process by adding at least one of only the three primary colour dyes to a base furnish. The colouring or tinting provides a tighter control for any shade of white paper while maintaining maximum brightness and opacity. The control is obtained at a reduced cost compared to the use of fillers. The method comprises the steps of selecting a set of optical properties for a required paper representing luminosity value (L), red to green colour difference value (a), and yellow to blue colour difference value (b) measuring the L, a and b values of a base furnish determining the deviations between the selected values and the …