Construction of Hand-Knotted Rugs – Dyes part 3 of 5
In the previous blogs in this series on Hand Knotted Rug Construction, we reviewed the foundation and the knots. Today’s topic is the dyes used to produce such intricate and beautiful patterns in hand knotted rugs.
There are many rug experts who are trained to be able to differentiate types of dyes – both with their “expert eye”, and through chemical analysis. This article is not intended to turn you into an expert, but to just share some basic information about dyes.
First, there are 2 primary types of dyes.
- Natural – also called vegetable or vegetal
- Synthetic – also referred to as aniline or chrome
There is a widespread belief that natural dyes are always superior to synthetic dyes. While it’s true that a quality antique hand knotted rug made with natural dyes is generally more valuable than one made with synthetic dyes, there are many more factors to take into account when valuing hand knotted rugs. For most people, the key questions you need to take into account when purchasing a rug is: are the colors pleasing to your eye and harmonious, or are they harsh and artificial? Will the colors develop more character and depth as they age, or will they fade or run noticeably?
Natural Dyes
As you would expect, natural dyes were the dyes used in the first rugs thousands of years ago, and continue to be widely used today. These dyes are all produced from nature – some colors from different plant material and some colors from insects! In historical times (and in nomadic tribes today), each group used its local indigenous materials in dyeing their yarns, so it was often possible to tell a rug’s origin by both the tribal pattern, and the predominant color palette.
To prepare natural dyes, you must gather the natural materials (plant or insect), dry it, grind it, and seep it. The yarn is prepared by first dipping it in a hot mix of alum or iron which prepares the wool to bond with the dye, and then the wool is cooked in vats of hot dye. The temperature, time, and number of different cooking periods depend on the color and shade desired. This is a very manual and time intensive process, and is why natural dyes are more costly than synthetic dyes.
Despite the higher cost, there is a reason rugs made with natural dyes are generally more valuable – it is actually hard to make natural colors look bad! With a skilled dyer, this process produces gorgeous colors with a lot of depth and character. Because you often have to use several different primary colors to produce the color you want (yellow and blue to make green for example), the resulting yarn will have a variegated color that shows specs of all of the colors used. In addition, natural dyes tend to be made in smaller vats leading to several different batches of yarn color that are not identical. Over time, these variations tend to show up more – one of the reasons antique rugs generally increase in value!
Natural dyes stable over time. You will find rugs in museum collections with vibrant rugs that are several hundred years old.
Synthetic Dyes
Synthetic dyes have a troubled history. The first synthetic dyes were aniline dyes introduced in the 1860s. These were horrible dyes that were extremely cheap and so were widely used to increase the production of rugs for export. These dyes bled, faded, and were very harsh to the eye. This ruined the reputation of hand knotted rugs, and aniline dyes were eventually banned in Persia (modern day Iran). Tradition has it that if anyone was found using aniline dyes the penalty was to cut off their right hand! These dyes are not used in quality rugs today – although some people still refer to all synthetic dyes as “aniline”.
Modern synthetic dyes are made of potassium bichromate (generally just called “chrome”) and thankfully for the tradition of hand knotted rugs, they are very good. They are easy to use, and produce a huge range of consistent colors that age extremely well. It is generally impossible for the non-expert to tell the difference between natural dyes and chrome dyes. The primary difference is that over time, the rug with natural dyes will develop more variegated color, while the rug with chrome dyes will maintain its more uniform color. This is an issue for those in the antique business, but generally not an issue for those who are using the rug in their home.
Well, that’s a very brief summary on the dyes! Next time we will cover another aspect of the construction of hand knotted rugs!
See Foundation part 1 of 5
See Knots part 2 of 5
See Wool part 4 of 5
Please let me know your thoughts in the comment section above.
As a rug designer, I am always interested in any valuable information I can pass along to my clients. With so many rugs on the market, education is particularly important. Thanks for sharing your excellent range of information.
-Barbara Jacobs