Лако-красочные материалы — производство

A test method for evaluation of tinting strength of colored pigments is briefly described here. A white reduction of the test pigment and another of the reference pigment are prepared by dispersing them separately in the same quantity of suitable solvent-free vehicle with an identical mass ratio of colored pigment to standard white pig­ment. Drawdowns are made of the test and reference tint pastes side by side on a paper chart. The color difference is then evaluated visu­ally or photometrically by an instrument to compare the strengths. The lightening power can also be evaluated by a similar technique but using a test white pigment and reference white pigment with a standard absorbing pigment as described in standard procedures.

Detailed information on visual evaluation of tinting strength is found in ISO 787-16, and on photometric methods in ISO 787-24, ASTM D387 and DIN 55986 and DIN 55603. The methods to refer to for lightening power of white pigments are ISO 787-17, ASTM D 2745 and DIN 55982.