Watercolor ultramarine 3.2 ml

The composition of the watercolor uses finely ground, concentrated pigments and highly purified gum arabic. A high degree of grinding on a ceramic paint mill gives transparent, pure and saturated colors. Watercolor mixes well, is easily washed and has high lightfastness.

In 1826 (according to some sources in 1827) Guimet discovered a method for preparing artificial ultramarine. Although, in fairness, the appearance of artificial ultramarine should be considered 1828 - the year Gmelen published his method, because Guimet kept his method secret until that time. In literature, an earlier date for the discovery of ultramarine by Tesar is sometimes given - 1814. The date of the beginning of industrial production is 1830, when Guimet built a factory for the production of ultramarine. Around the same time, its production began at a porcelain factory in Meissen. In 1834, Guimet demonstrated his ultramarine at the Paris Industrial Exhibition. The company Winsor & Newton had been producing artificial ultramarine for oil and watercolour painting since 1832.

Artificial ultramarine has been produced in Russia since the mid-19th century. Since the discovery of artificial ultramarine, many methods and recipes for its preparation have been proposed. At first, the raw materials in industrial production were kaolin, Glauber's salt, soda, sulfur, infusorial earth and coal or coal tar pitch. The mixture obtained from these components (for example, 100 parts kaolin, 105 parts Glauber's salt, 23 parts coal, 16 parts soda and 20 parts sulfur) is placed in crucibles and fired without air flow in furnaces at 750 - 770 ° C. The resulting mass, after proper cleaning and drying, can be used under the name "green ultramarine". To obtain blue paint, green ultramarine is again subjected to calcination with an admixture of a new amount of sulfur (8%) with access to air. As for the proportions of the above-mentioned materials included in the mixture subjected to calcination, changes in the composition of the mixture can be allowed within the widest limits, which, of course, affects the quality of the product and causes the appearance of different shades of paint. •

The color, intensity and glazing ability largely depend on the degree of grinding of the pigment - the finer the powder is ground, the higher the quality of the pigment - higher color intensity and a purer tone.

Being a strong reducing agent, ultramarine destroys most biocides (their active components). In this regard, there is a difficulty in selecting preservatives for ultramarine paints.

Artificial ultramarine is inferior in many ways to its natural analogue.

Chemical description: Ultramarine is a synthetic sodium aluminosilicate with the inclusion of sodium polysulfides.

•Chemical formula: n(Na2O Al2O3 mSiO2) Na2Sx

•Lightfastness – 6-7

•Alkali resistance: 5

•Lime resistance: 5

•Acid resistance: 3

•ColorIndex PB 29

•Color deep blue

•Form cuvette 3.2 ml