How Do We Tell Natural (Madder) Dyes from Synthetic Dyes?

⏱ Reading time: ~9 minutes · Last updated: July 2026

Rug lovers often ask, “How can you tell whether a rug's dye is a natural madder dye or synthetic?” But before the answer to “How is a madder-dyed rug recognized?” we should ask why it makes a difference how the dye was made.

Many rug collectors agree that natural dyes are more attractive than synthetics. In fact, whether a rug takes its color from a plant extract or a chemistry lab makes no aesthetic difference at all.

So then, why do rug collectors care about the answer to this question? The answer is actually very simple. Knowing whether a rug's color is natural or synthetic allows one to estimate the rug's age and average market value. Because madder-dyed rug prices are higher than the prices of synthetically dyed rugs.

How Is the Type of Rug Dye Determined? General Methods for Determining the Type of Rug Dye

Two methods are used to determine the type of rug dye. These are called chemical analysis or the trained-eye test (a term, I believe, coined by George O'Bannon). Both methods have their own advantages and disadvantages.

Chemical Analysis:

In the chemical analysis of dyes, a method called chromatography is generally used. Chromatography separates the chemicals in a mixture and, from the behavior they show during separation, provides information about the structure of the mixture. Sometimes this method is combined with spectroscopy, a physical technique that measures what our eyes perceive as color. Even the poorest of chemical-analysis methods such as chromatography and spectroscopy are more accurate at identifying dyes than the “trained eye.”

In today's textile-science literature the gold-standard method in this field is known as HPLC-DAD (High-Performance Liquid Chromatography – Diode Array Detector). Academic research shows that the natural reds obtained from the madder plant (Rubia tinctorum, also known in Turkish as “boya kökü” or “kızıl kök”) are in fact a distinctive mixture of specific anthraquinone molecules such as alizarin, purpurin and, in smaller amounts, nordamnacanthal, and that these molecules can be precisely detected with HPLC-DAD. That is, what we call “chemical analysis” is no longer an abstract concept; laboratories know exactly which molecule they are looking for.

The greater reliability of chemical analysis is an advantage. But this method has a number of disadvantages. First, chemical-analysis methods are expensive. Even the cheapest method, thin-layer chromatography, can be set up at home with an investment of a few thousand dollars. More complex forms of chromatography require tens of thousands of dollars in start-up costs. And if spectroscopy is to be included in the analysis, the cost of the laboratory can exceed figures of nearly $100,000.

Moreover, serious training and skill are needed to use chemical-analysis methods. For most people, sending samples to a central laboratory for analysis will be more practical than setting up the equipment at home.

Another disadvantage of chemical testing is that obtaining results takes time. Samples are first taken and then sent to the laboratory. Results can take hours, days, sometimes even weeks to arrive. This creates a serious problem, especially for potential bidders at auction or for those many sellers describe as “opportunist collectors.” Since most rugs have 5 to 15 different colors, several samples must be taken from each rug for analysis. And to take a sample, part of the rug must be cut. So it is unrealistic to expect sellers to be very willing about this. It is therefore no surprise that chemical analyses are rarely used.

The Trained-Eye Test

Although the “trained eye” test is not as reliable as chemical analysis, it has many advantages in practical situations. There is, however, the possibility of an error such as identifying some synthetic dyes as being of natural origin. Even so, after acquiring a little knowledge almost anyone can develop their “trained eye.” One thus has a fully portable, fast, cost-free, non-damaging and quite reliable testing method.

How Is the Trained-Eye Test Learned?

Some elements of identifying dye types by eye can be learned from books. But the ability in question is not gained by examining photographs found in books. Because photographs cannot reflect colors accurately.

The best way to develop the trained-eye ability is to learn from someone who already has a trained eye, itself trained by someone else in the same way. In this way the chain of experience reaches back into the past.

The eye-identification method also has some risks. The first is that erroneous identifications, which vary from person to person, come to be accepted as truth as they are repeated. Another risk is that, since natural and synthetic dyes have a very wide color range, thousands of examples must be examined to train the eye.

So where can we find people with a competent trained eye? And once we find them, how can we prepare, in order to learn the answer to how a madder-dyed kilim is recognized, an environment with enough kilims or rugs for these people? In this respect, knowledgeable sellers can help solve this problem by using their inventory as examples.

But having many teachers and many examples will be far more beneficial than a few sellers ready to share the examples in their limited inventory. For this reason, the two best places to receive training are the dealer fairs at rug congresses and the previews of auctions held at major auction houses such as Sotheby's, Christie's or Skinner's.

There you can see, touch and discuss several hundred to several thousand rugs in a single place. Moreover, you have the chance to ask questions of many people with expertise. Collectors, sellers and auction-house staff are all potential teachers. They are also generous about sharing their time and knowledge.

Some Basic Rules for Beginners

To develop a trained eye, looking at as many madder-dyed rugs as possible and receiving training from experienced people is essential. But there are also some simple starting steps you can take in your reading nook. Let us look at these a little.

Whether blue is natural or synthetic is somewhat debatable. Because the madder — rather, the natural dye — used for blues is the same chemical as synthetic indigo. Indeed, indigo is a preferred dye for the blues in contemporary fabrics, including jeans. One of the interesting things about indigo is that it dyes only the surface of the yarn, not its whole thickness. The scientific reason is that indigo is a “vat dye”: indigo is insoluble in water, and the dyeing process requires first reducing it to make it soluble, then re-oxidizing it once the yarn meets the air to give color; this chemical cycle causes the molecule to attach to the surface of the yarn rather than its core. That is why, when the surface wears, the natural color of the yarn appears. This is also the reason jeans “fade.” In fact no fading of the color occurs. The yarns have high and low regions. When the high regions wear, they take on a white look, so the jeans appear faded to our eyes.

If you have ever tried to deal with grass stains on children's clothes, you may be surprised to learn that natural green dye is quite a rare thing. The palettes of some very early Turkmen works contain natural dark green. But most of the greens seen in the types of handwoven kilims produced using madder before the discovery of synthetic dyes were obtained by dyeing the yarn successively with indigo (woad blue) and natural yellow. When green madder dyeing is done this way, it is quite easy to recognize. Because some natural yellows are quite sensitive to light. In rugs dyed with such dyes, the color on the light-exposed surface becomes blue while the back shows that the rug was once green. Another clue that a green is a natural madder dye is wear on the yarn surface. Yellow patches appear on surfaces where the indigo layer has worn away.

Blacks and dark browns, although sometimes obtained naturally from sheep with dark-colored wool, were usually produced using dyes that have a corrosive effect on wool. For this reason dark brown or black areas wear more quickly than other colors, and a pronounced relief effect could be seen. In many old rugs the blacks or dark browns are so worn that the pile in these areas is almost entirely lost.

A word of caution: many a modern kilim, especially Turkish products with Caucasian patterns, has black areas cut deliberately at a shorter pile height than the other colors. One way to distinguish these from naturally corrosive blacks is that the wear in areas dyed with corrosive blacks varies from one part of the rug to another.

Purple madder dyes are relatively rare. But a purple antique madder-dyed rug can easily be told from synthetic purples. Purple madder dyes are very sensitive to light. Usually, when the pile is pushed back or the back is turned over, pale tips and vivid purple bases can be noticed. There are, however, some weaving groups that use corrosive natural purple.

The color group where it is hardest to separate natural and synthetic dyes is the reds. Both natural and synthetic reds have a very wide range of tones, and the only way to be experienced in this is to see many examples. Early synthetic reds (and some contemporary red dyes) are prone to color bleeding. But the presence of red bleeding does not indicate that the dye was not obtained from the madder plant. Some synthetic red dyes so closely resemble madder tones in appearance that even the most experienced eyes can be deceived — indeed, academic analyses done with HPLC also show why this distinction must be confirmed not only by eye but at the molecular level. On the other hand, those with truly trained eyes must also have a trained mind that is aware of this problem.

Oranges and yellows create problems similar to those of reds, but they usually appear in far smaller areas of a rug than reds. Apart from the early synthetic orange with a striking exuberance, these are rarely the only synthetic dyes in a rug's palette.

Finally, there are also rugs whose palettes have very vivid colors and whose tips have largely faded. This becomes much more evident when the pile is opened so the bases of the knots can be seen. These rugs contain many synthetic dyes and are usually Persian or Caucasian weavings made between World Wars I and II (roughly the second quarter of the twentieth century).

Final Word

There is no doubt that identifying dyes through chemical analysis is far more reliable than the “trained eye” method. But because chemical analysis is not practical and is quite expensive, it does not seem likely to be widely used in the near future either. The rugs for which the analysis expense is likely to be only a small part of the total cost are only the most expensive and usually very old rugs. But these are also the rugs for which the “trained eye” is least likely to make an error.

There are few experts who test rug dyes, and one of the best known is Paul Mushak of Durham, North Carolina. By my estimate, fewer than 500 kilims have had any of their colors subjected to dye analysis to date. The number that have had all their colors tested is probably at most 10 to 20. If we consider that the major auction houses on the U.S. east coast put roughly 10,000 kilims up for sale every decade, and that each of their catalogs states an estimated age based on a visual examination of the dyes, you can understand how firm a place the “trained-eye test” has secured in the rug world.

I believe every serious collector owes it to themselves to train their own eyes, and that there is no way to do so other than seeing many a madder-dyed kilim and letting more experienced people be your teachers. Remember that the material must be verified as well as the dye: we explained the tests for distinguishing genuine silk from silky fibers such as viscose and bamboo, especially in silk rugs, in our “Silk Rug Guide”.

Frequently Asked Questions

What is madder dye?

Madder dye is a dye obtained from natural sources such as plant roots, leaves or flowers. Its best-known example is the madder plant (Rubia tinctorum).

How is a madder-dyed rug recognized?

It is recognized either by the definitive but expensive chemical analysis (HPLC-DAD) or by the fast but experience-demanding trained-eye test.

Which color is the hardest to tell whether it is madder or not?

Reds; both natural and synthetic reds have a very wide range of tones.

What is HPLC-DAD?

It is a chromatography method that scientifically confirms whether a dye is natural or synthetic by detecting molecules such as alizarin and purpurin in natural dyes.

What is the difference between blue madder dye and synthetic indigo?

They are chemically the same. Because indigo is a vat dye, it dyes only the surface of the yarn.

Why are madder-dyed rugs more expensive?

Because they are usually older, rarer and go through a more laborious production process, they command higher value in the collector market.

Related posts: What Is a Vintage Rug? · Rug Pattern Guide · How to Tell an Antique from a Vintage Handwoven Rug · Kilim Motifs and Meanings · Silk Rug Guide

This article is reprinted with the permission of the author, Steven Price, and can be found on the TurkoTek website.