Synthetic Organic Pigments

At first this seemed a tremendous gain for art. However, it has turned out to be a treacherous gift. It soon became evident that the aniline dyes, developed first, soon lost their splendor in sunlight, and even pigments made or toned with them were subject to bleaching. Although the damage to painting by these defects has been exaggerated, the author knows of some tragic cases where artists saw the beauty of their watercolors, painted with these pigments, fade. During the first quarter of the twentieth century new types of aniline colors were discovered that possessed better properties. The azO- and Indanthren- groups have become the best known of them.

The worldwide reputation of the German dyestuff industry began with the above-mentioned indigo group. Madder was a similar case. It consists of the fugitive purpurine and the relatively light-fast alizarin. Once the artificial production of pure alizarin was possible, alizarin madder became a pigment far superior to that made from natural madder root. In an agreement made between artists and industry at Hannover in 1908, it was decided that any coal-tar dye used for artists' pigments should at least be as light-fast as alizarin madder. Meanwhile, Professor Dr. TÉuber has found a similar dye, purpurine carbonic acid, which surpasses the beauty and light-fastness of alizarin. Unfortunately this discovery has so far not been exploited by the color industry, because artists represent too limited a consumer group and reproduction would therefore not be sufficiently profitable. This is also the reason why no money has yet been invested in research, which today would most probably lead to the synthetic production of magnesium euxanthate, the principal constituent of Indian yellow. In any case, the introduction of synthetic organic colors has meant an advance. Although the first serious setbacks have been overcome, public institutes for paintng technique must still carefully test new products before artists can rely on them. To be sure, [p. 54] industry itself has exact testing methods but the quality of the production is not determined by the artists. The demands of artists, however, must be very strict.

Apart from the fine arts, colors have such a diverse range of application today that the demands upon the material have become very varied. [pp. 54-55]