COLOUR IN LIFE.

Hokitika Guardian, 3 April 1924, Page 4

COLOUR IN LIFE.

NATURAL AND ARTIFICIAL DYES

It lias been the custom of man throughout countless ages either to stain his body varied hues or to bedeck himself in brightly coloured raiment. From time immemorial colour has played a tremendous part in mail’s dross, and until the 19th. century all these colours were obtained from natural sources.

Indigo, one of the oldest known dyes, was formerly obtained from a plant found in India, Java and South America, and known as Indigoferae, the juices of which are yellow, but on exposure to air turn blue. That indigo has been known thousands of years Is evident- from tho fact that garments found in graves in Peru were dyed with this colour. Mummies found during excavations in Egypt wore wrapped in cloths dyed with indigo, which proves that the ancient Egyptians were conversant with this colour. Strange to relate, when Julius Ceasar first led a Roman army into England almost two thousand years ago, he found the ancient Britons adorning their bodies with a dull blue colour known as woad. This colour has been proved to be indigo in ail impure form. For a red dvo our ancestors used cochineal, wliic-li was obtained from a small insect found in Central America. These insects were specially cultivated, and when full grown were simply dried and put on the market. When these were dissolved in water a brilliant red colour was obtained, and for a considerable time this was the only dye used to dye the scarlet coats of the British army.

The principal yellow colour was obtained from the flowers of the yellow crocus, and was known as saffron. This was afterwards superseded by a more powerful yellow dye known at turmeiie, and obtained from a plant growing in India and China. From India also came dyes known as outch. and gambier, extracted fijcmi leave.') and nuts etc., from which rich shades of brown were obtained. By far the most important vegetable dye to-day is logwood, which furnishes excellent blacks on wool and silk, and is largely used by the tanners. It is extracted from a tree growing in the West Indies, and was first introduced into England in Queen Elizabeth's reign, much to tho annoyance of one section, of tho dyers, who had its importation prohibited by Act of Parliament. It was over a hundred years before the Act was repealed, and logwood universally used. A hundred years ago the dyer bail a very limited range of colours at his disposal—-to-clay he has thousands to choose from, and is still far from satisfied . ARTIFICIAL DYES. The manufacture of artificial dyes dates hack to 1806, when a young chemist named l’erkin made a remarkable discovery. It had lieen the custom to charter a boat to take out to sea all the coal tar accumulated by the various gasworks, and “dump” it. The reason for this needs no finding. The introduction of illuminating gas, which took place, about the beginning of the nineetenth century, meant that everyday the various gasworks were making tons of tar as a by-product, and for which they could find no use. It was soon apparent that as the illuminating gas industry advanced some use must be found for this “foul-smelling liquid”—coal tar. Research work was commenced, and, piineipallly owing to the work of Holman, benzene was extracted from it. Further research work turned the benzene into aniline, and it was from this product that the chemist, Perkin obtained the first aniline dye. Perkin became obsessed with the idea, that be could make quinine from this aniline, but insead of obtaining the beautiful white crystals he had hoped for, lie obtained a black porous mass which to his surprise dissolved in alcohol with a beautiful violet colour, which dyed wool and silk a beautiful mauve. Naturally, such a discovery excited the chemical world, and it was not very long before other chemists working on the same lines as Perkin discovered better and more brilliant dyes. I’erlcin took out a patent for bis discovery, and a factory was established for its manufacture in Manchester. The next discovery of interest was the manufacture of artificial alzarin by two or three firms, only one of which is manufacturing in the British Empire.

Since the advent of Perkins’s mauve dye never a year lias passed without more synthetic dyes being added to the list, and as the industry gains ground the colours produced are becoming of greater fastness. Although prior to the war, the dye business was monopolised by German and Swiss manufacturers, due chiefly to the apathetic British Government, and the natural British disregard for research work, British firms have been making a bold hid for supremacy. "Whether they have succeeded in equalling or excelling the German products is a matter of opinion, each dyer having his own opinion of their merits and demerits. The fact, however, remains, that there is a long way to go before we reach the high standard of dyes we had before the war. There is much research work to he done, and many colours still to be made, which have not yet been made outside Germany, before the various industries which use dyes will be satisfied.

It might he mentioned that the “so. called secrets” of German dyes are only secrets in this way. They are secrets of much research work, of careful plodding and infinite patience, of attention to detail and of careful manufacture. They are secrets of careful standardisation, and above all of supplying goods up to sample. The German dyes of today are the same as they were before the war. They are always uniformly the same, which is more than can be said for the dyes of some of the British manufacturers.