Perhaps the most appealing attribute of oriental carpets is their wealth of colour, and this charm on the sheen and texture of the wool from which each individual carpet is made. The splendour of the colours, their lustre and sheen, are perhaps to be attributed to the fact that the oriental craftsmen often come from the most primitive strata of society, living still on a nomadic, or semi-nomadic level, as yet untouched by the influence of more advanced civilization. They have a natural artistic sensibility, and the simplicity of their lives has led them to develop to high degree a sense for colour and its complementary rhythms. Their innate artistic feeling enables them to distribute the colours and divide these so that do not clash, but attain a significant harmony. Be this as it may, the best carpets seem to achieve a wonderful effect of richness and splendour. But its important to realize the difference between the old colours obtained from natural dyes, whether vegetable or animal, and the modern chemical dyes obtained in the first place from Europe. Aniline and alizarin dyes have been used to some extent in most parts of the Orient since the end of the impart the glowing effect of the old vegetable dyes, and when bright they look merely garish and crude. The early chemical dyes which were obtained were misunderstood and improperly compounded; most of them proved extremely lacking in colour-fastness. Although the old vegetable dyes often fade to a greater or less extend, they seldom lose anything of their original beauty, and the best of them are relatively fast. Particularly fugitive are mauves, violets and greens. Chemical dyes, particularly in the early period of their use, proved highly detrimental to the quality of oriental carpets. Since then the more far-sighted manufacturers and weavers have avoided this abuse, caused by the importation of cheap chemical dyes, and although an attempt to forbid the importation of synthetic dyes proved abortive, their use has generally become better understood and more limited. Synthetic dyes are found least of all in the Turkoman carpets. In fact, they hardly penetrated at all into the inaccessible regions inhabited by these nomad tribes.
It is always important to establish the colour-fastness of the dyes of a given carpet. This can be gauged to some extent by examining the front of the carpet in contrast to its back and observing the relative degree of fading. By bending back the knotted pile and examining the wool near the knot, one can see how much fading has taken place at the surface. To establish the tenacity of a given dye a rug may be dampened with hydrochloric acid and rubbed hard over the colour in question on the front of the carpet. Most chemical dyes will be revealed by this test. If hydrochloric acid is not at hand, a quick test can be made by moistening a handkerchief with water; a fast colour should not be moved by this, but it will be found that with hard rubbing many colours will tend to be moved. When carpets are washed, as all carpets must be in the course of time, dyes which are not truly fast to water will tend to run. This running of colours is always discernible to an experienced eye and is a sign of faulty dyes. It should be remembered that many oriental carpets are made with partly vegetable and partly chemical dyes, and therefore considerable discretion is to be used in assessing their value. The best synthetic dyes will stand up to the washing test, and also carpets where the colours have been fixed with the use of certain chemicals, such as chlorine.
Natural dyes are mostly made from plants in the form of roots, seeds, stalks, rinds of fruit and suchlike. The colours obtained from vegetable dyes tend to vary a great deal in shade. The reason for this lies in the technique of dyeing into which a number of imponderable factors enter. Madder root is a source for many shades of red, and the age of the root plays an important part in establishing its tone.
BLUE is obtained from the indigo plant through oxidization with air.
YELLOW from the stamens of saffron, a kind of crocus, an excellent yellow is obtained, but it is a rare and valuable colour and for this reason very seldom used today. Yellow is also obtained from vine leaves and the rind of pomegranates.
DARK BROWN AND BLACK are obtained from the gall-nut, a parasite which lives mainly upon oaks; but black dyes usually contain a certain amount of iron oxide and this is a great disadvantage, since with exposure to light the acid tends to eat through the woollen fibre and dissolve it in time. It may frequently be noticed that the black parts of old carpets have worn very much lower than the other parts of the pile. Sometimes this gives the effect of a pattern standing out in relief against a dark ground, but whether this effect should be admired is highly questionable since it is purely fortuitous and it is in fact defect. In some of the best carpets, wool from black sheep is used; needless to say it does not suffer from this disadvantage.
UNDYED BROWN wool from sheep and particularly used, especially in Hamadan carpets and those from the Karabagh region.
UNTREATED WHITE sheep's wool does not look pure white but is grayish or yellowish in tone; if it is not it may be suspected of being chemically treated.
GOOD RED is derived from kermes, which is beetle gathered from the kermes oaks or cacti. The shells of the beetles are dried and yield an excellent dye.
PURPLE in antiquity, purple was a highly prized colour and was obtained from a certain type of seashell. Purple is normally obtained from the blending of red and blue dyes.
PINK is a relatively rare colour. A peculiar light wine red which is almost pink is a favourite colour in carpets from Karabagh region.
GREEN is a rare colour for the ground of a carpet since it is the sacred colour of Mohammedans and associated with the Prophet. No believer will step on a green carpet with his feet. None the less, as a complementary colour in the pattern, green is often found in the older carpets, such as the Vienna Hunting Carpet. When green is found in prayer carpets, the sacred use of the carpet sanctifies the colour.
Occasionally it will be noticed that a particular colour shows a marked change in different parts of the carpet; sometimes there will be light and dark stripes of the same colour. This need not be regarded as defect in the carpet. On the contrary it is sign of a carpet made under simple conditions by a nomad tribe or in a primitive home. The nomad does not want to burden himself and his animals with pots of colour during his trek. He will prefer to make up a little colour, use it, and count on making up a fresh supply when he has moved to new pasture - lands. Often, however, he does not succeed in exactly matching the colour at the next halt where conditions may be somewhat different; the shade of the colour will therefore vary in tone from one end to the other. Often it may be said that these variations serve to enhance the quality of the carpet. It should also be remembered that with Mohammedans a certain unevenness and lack of uniformity in their works of art matches with their religious views, since the Mohammedan does not consider it right for man to create anything perfect. Only Allah is capable of perfection, therefore nearly all Islamic carpets show definite and intentional irregularities in the pattern. Once can observe this particularly in the corners. Whilst machine-made European carpets will show complete regularity of pattern, asymmetry is the hallmark of the genuine oriental carpet. For the same reason the oriental prefers uneven numbers. Another characteristic may be noticed, namely that rugs made by nomadic tribes, and particularly the Turkoman herdsman, are dark in tone, for these people who spend so much of their day in the glaring sunlight find relief and joy resting their strained eyes on dark colours in the home.
Oriental Rugs, Page 57-60, Herman Haack, 1960