Лако-красочные материалы — производство

For standards, see Table 1.1 (“Scattering power, relative”). The relative scattering power S is the ratio of the scattering power ST of the test white pigment to the scattering power of a white reference pigment SR [1.55]. It can be determined in two ways:

1. Black-Ground Method. The relative scattering power is determined from the tristimulus values Y of the pigmented medium applied in various film thick­nesses to black substrates. Compared with the gray paste method, the black — ground method has the advantage that it is not restricted to any particular test medium. Apparatus: spectrophotometer.

2. Gray Paste Method. The relative scattering power is determined from the tris­timulus values Y of gray pastes. The method has the advantage of being less time consuming than the black-ground method. The results of the two meth­ods are not, however, generally in agreement. Materials and apparatus: black paste, spectrophotometer.

1.3.4