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Dyes
Three types of dyes have been used in the dyeing of Oriental rugs:
natural (vegetable or animal), aniline, and chrome. Aniline and chrome
dyes are synthetic dyes.
Natural Dyes Vegetable and Animal
Making and using natural dyes is tedious and time-consuming
and can be quite expensive. The colors are derived from a number of
different sources depending on what is available to the dyers. When local
abundance of a natural source makes it economically feasible, vegetable or
animal dyes are still used.
These sources vary from country to country. The most common of the natural
sources:
In older rugs there often appears a
slight change of color which will
run horizontally through the field of the carpet. This is called an abrash. This occurs when the weaver begins using
yarn from a different dye lot than that previously used. With natural
dyes, it is quite difficult to obtain an exact color match. This is
not objectionable in itself and does not affect the value of the rug.
Aniline Dyes
The use of aniline dyes was introduced
to the carpet industry in the latter half of the nineteenth century.
Being easier and cheaper to use, these dyes were all too readily
adopted. They were strongly acidic, which destroyed the natural oil in
the wool, thus weakening the pile and causing it to wear rapidly. The
colors not only faded when exposed to sunlight, but ran when washed.
The use of these dyes was not limited to one area but spread
throughout the rug-weaving world. Aniline dyes are not as widely used
as they once were; their use is generally limited to inferior-quality
rugs. In older rugs aniline dye can easily be recognized by the faded
color of the pile; the back of the carpet will be much brighter than
the sunlight-faded front. To check for aniline dye in new rugs, rub a
damp cloth over the pile. A good-quality vegetable or chemical dye
will not rub off onto the cloth. If a color does appear on the cloth,
an aniline (or other inferior) dye has been used and the rug should
not be purchased.
Chrome Dyes
The majority of rugs are now dyed with
what are commonly referred to as "chrome dyes." These are synthetic
dyes which have been treated with potassium bichromate. In contrast to
the natural dyes, chrome dyes are much cheaper to use, simpler to
prepare, and their dye lots easier to match. These dyes provide a
wider range of shades and colors and are colorfast; they will not fade
when exposed to sunlight, or washed with water or an alkaline
solution. The natural oils of the wool are not removed by the dyes, so
the wearing qualities of the rug are not impaired.
The major complaint about the early
chrome dyes was that their colors were harsher than the hues of the
natural dyes. This problem was corrected by the use of a light
chemical wash.
Chemical Wash
Most rugs are given a light chemical
wash before being exported. This wash simply enhances the richness of
the rug and does not affect its durability. A luster, or sheen, may be
given a carpet by the chemical wash. Several factors affect the amount
of luster imparted: the type of wool used for the pile and the
chemical concentration of the wash. Wools vary from region to region;
certain wools are more receptive to the chemical wash, gaining a more
lustrous appearance than others.
An "antique" wash has been developed to
give new rugs an old look. This is a rather heavy chemical wash which
tones down the colors and gives the impression of being an antique
rug. Rugs with an "antique" wash can be detected by splitting the pile
and examining its base. The top of the pile will have a drabber, muter
color than the base. The wash also gives the fringes a brownish cast.
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