The composition of watercolors uses finely ground, concentrated pigments and highly purified gum arabic. A high degree of grinding on a ceramic paint grinder gives transparent, pure and saturated colors. Watercolors mix well, are easily washed and have high lightfastness.

Cadmium red. A whole line of pigments. According to the chemical composition, they are mixed crystals of cadmium sulfide and selenide CdSxnCdSe, the color of which, depending on the content of CdSe, can vary from orange to dark cherry. Usually contain an admixture of heavy feldspar (from 58% in dark and up to 76% in light colors). These pigments form the brightest and purest range of red shades. This group includes red cadmopons (a mixture of CdS + CdSe + BaSO4). Cadmium sulphide has been known since 1817, patented in Germany in 1892. As a pigment, light cadmium red has been used since 1910, dark since 1920, sometimes instead of cinnabar.

Cadmium red does not dissolve in alkalis, acetic and dilute sulphuric acid, slightly soluble in dilute hydrochloric acid. Dissolves in concentrated hydrochloric and nitric acids and a saturated solution of ammonium chloride. Dissolves in aqua regia. Heat-resistant up to 350°C, and in the absence of oxygen - up to 700°C. Above 600°C it turns black.

Red cadmium pigments have good light resistance and fairly good weather resistance. When mixed with zinc or titanium white, light resistance drops. These pigments do not grind, are easily dispersed and do not have a chemical effect on most film formers. It is not recommended to use red cadmium together with pigments containing lead, copper and some other metals that form dark sulfides.

Undesirable mixtures of cadmium paints:

• mixtures of cadmium paints with ultramarine, violet madder and Van Dyck give them a lightening, but the paints retain their color;

• the entire group of cadmium paints is prone to erosion in the aging film, which was noted in mixtures of cadmium paints with cobalt, manganese, ultramarine, light ochre and volkonskoite.

• with dark ochres, brown mars, natural umber, ultramarine, as it can cause lightening or contamination of the tone.

•Chemical description: Cadmium selenide.

•Chemical formula CdSe

•Alkali resistance: 5

•Lime resistance: 5

•Acid resistance: 5

•Lightfastness - 8

•ColorIndex PR108

•Color Red

•Form cuvette 3.2