Pierre Galafassi

Dear TTekers,
My statement about the near impossibility to detect modern synthetic dyes on rugs without significant lab work, might have been a strong disappointment for many.
However, as mentioned by Steve, TLC does not require any expensive hardware, could be performed at home without necessarily leading to a divorce with either wife or banker and would still allow to reach interesting conclusions.
Home-made TLC will never identify all dyes on your rugs (since most required reference dyes cannot be bought), but could easily answer the limited question "Is the red dye in my rug truly madder or cochineal ?" for example.
Steve has saved on the server a description of hardware and method, for anybody wanting to start a new career as TLC cottage guru.
The url is http://www.turkotek.com/journal/dyes_TLC.pdf
Enjoy.
Pierre

Note: The link above now leads to an improved version of the document.

Horst Nitz

Hi Pierre,

first, thanks a lot for that brilliant essay on the matter.

It may not be too difficult to set up ones personal reference library of dyes. What it needs is a number of samples (one or two knots from each rug should be sufficient) from trusted rugs. Running them against one another should show them equal in at least one or two of their main components (Alizarin, Purpurin, Pseudopurpurin) if the dyes are truly built on madder. What the common main components are can easily be assessed, since to some degree not only qualitative answers can be elicited, but also quantitative ones (area of blot, colour density etc.) Any other suspected red dye, i.e. artificial, that has to run against that collective (or is to be compared with it - conditions all equal) should show a much different distribution in the zone of main madder components as well as in the overall - in a given solvent mixture.

For our practical purposes the reference library of artificial dyes may not need to be very comprehensive either. If I aim for a differential analysis natural vs. artificial in a let say late 19th c Central Anatolian rug, I may be able to buy a complete reference library in the form of two or three rugs of the matching area and period on regional flea markets.

Does this sound reasonable to you? Actually, TLC may appear somewhat dated only from our super elevated stance in time; to researchers like Schweppe or Whiting in their days it must have been a leading edge technology. Few of the dyes that were developed after their researches (1950-80) are what we are looking at in the rugs we are interested in anyway. In this sense the technique is still fully up to the job - and much fun! Hmm, if I only think of all this lovely amyle acetate, acetic ester and chloroforme involved....

Thanks again and let's have fun,

Horst

Pierre Galafassi

Hi Horst,
I have a feeling that you plan to rob your kid’s magician outfit, Uh?

I agree with you. TLC is a very good method. As you put it, «fully up to the job».

To identify the usual natural reds and blue is perfectly feasible for any gifted amateur. Pure samples of these dyes are easy to get on internet. No need even to ask Madame Tzareva for a piece of her Salor khali. As you say, the same five or six dyes are found in various concentrations in the different botanical varieties of madder. With a sample of two or three madder varieties (R. Tinctoria and Munjeet for example) the field is nicely covered.

It will be a bit more tricky for the natural yellows (including tannins), since the number of candidates is much higher and samples of some major plant extracts are not so easy to find. However 3 or 4 dye molecules are much more important and frequent than the others.
Seeds of most of the plants can be bought. Two friends of mine have even started a little dyeing-plants section in their gardens. Its fun, even though local rabbits feature funny shades. (I shall post a list of the main plants and dyes used in rugs, based mainly on Drs. Böhmer and Schweppe superb books).

With these reference samples of natural dyes and playing with various solvent mixes, you will be assured to identify the main natural dyes, thus answering with reasonable certainty the main question: Synthetic or Natural???
If it is not an identified natural dye, it must be synthetic, the chance that it would be an unknown natural dye is reasonably low and keeps decreasing with increasing number of reference samples of natural dyes in your collection.

Never mind the identity of the synthetic dyes!

But if you really would love to identify as well synthetic dyes, then you would be well advised to aim only at the 1:1 chrome dyes. A small number of them have dominated the market for the past eighty years at least. With a little bit of luck, reference samples can be obtained from the dye suppliers.

Trying to identify dyes from the previous generation (1858-1920) is a lost battle. In the early phase of the industry, new dyes were created by the thousands and tried on wool by the hundreds. No way to get samples of most of them. Even Dr. Mushak a true expert of the field, rarely managed to identify synthetic dyes in ancient rugs, no doubt for lack of reference samples. The idea of buying a XIX century rag on the market is brilliant, but will probably yield only a few references of old synthetic dyes.

Ooh, about solvents: a very efficient one is Cabernet Sauvignon. In my next post I shall explain how to use it.
Best regards
Pierre

Pierre Galafassi

Hi Horst,
The tables below show the main tinctorial plants and insects used for dyeing yellow and red shades on rug wool and the main dyes in each plant.
The list may seem very long, but fortunately some dyes are likely to be found much more frequently and in higher concentration than others on rugs. I believe also that some Eastern Asian plants had only a local importance and never went West in any significant way.

Thus, I would guess that one can do a pretty good TLC job with:

For yellows: powder samples of the first five plants listed (Reseda Lutea, Matricaria chamomilla, Alium cepa, Delphinium zalil and pomegranate). They will allow to identify the important dyes Luteolin, Apigenin, Quercetin and Rhamnetin and two types of yellow tannins.

For reds: powder samples of Rubia tinctoria , indian madder and american cochineal . Enough to identify on TLC plates all the main red chromophores (Alizarin, pseudo purpurine, purpurine, munjistin and carminic acid)

Blues are a piece of cake.

You may want to addd a sample of Juglans regia, which main dye juglone was an excellent brown (direct) dye and probably reasonably frequent, but perhaps less used than brown wool shaded with the mentioned reds and indigo.

The Museum of Applied Arts, Budapest, has identified the natural dyes present on a large number of its (turkish) rugs, the results were published in F. Batari’s «Ottoman turkish Carpets». It gives a pretty good idea of which dyes were important in this region of Rugdom, between XVI and mid XIX centuries.
Have fun!






Regards
Pierre