Weigh 0-1 gram of the test group, 1 gram of standard zinc white well and 15 drops of raw flax oil (0.7 grams), put this mixture on a glass plate or a porcelain plate, and carefully adjust it into a uniform mixture with a pair of knives. slurry. Then make a slurry with standard ultramarine blue and the same weight of zinc white and oil. The amount of standard chrysanthemum in the formulated pulp gradually decreased, or on the contrary gradually increased (0.098; 0.075 or 1.05; 1.10; 1.15). From the pulp made with the standard group, select the pulp with the same shade as the sample. When comparing color light (related instrument: Colorimeter), the two pastes must be painted on the glass plate in rows, and then inspected through the glass plate under reflected light. The coloring power of the tested ultramarine blue can be represented by the following formula:
