Many customers ask the question, are the dyes in this rug vegetable or synthetic? The only way to answer this question without taking a sample of your rug to a laboratory for chemical testing is for an experienced professional to inspect your carpet.
Synthetic dyes were introduced in the late 1800’s, and were widely used by the 1920’s. Therefore, not all “antique rugs” today have vegetable dyes. Your 90 year old carpet may very well have synthetic dyes.
There are a few shortcuts to determine whether your rug has natural or synthetic dyes, however they do not apply to every Oriental rug.
Turkotek has some fantastic educational tips on telling the difference between synthetic and natural dyes. Natural green dyes are rare, they were originally made by combining a yellow plant dye with blue dye obtained from indigo. Due to wear, or sun exposure the blue or yellow color can fade causing the green to disappear and leave one of the original colors in its place. By flipping the rug over and examining the back, you will see the original green still remains on the backside because it has not been exposed to sunlight or traffic. This tells you your rug is made with vegetable dyes.
One synthetic dye in particular stands the test of time and is a bright orange. This color won’t fade and it is a sure way to tell your rug has synthetic dyes. Another synthetic dye, purple, will fade quickly into a grey colored tone. If you turn your rug over, or pull back the pile you can usually see the original purple color.
Don’t despair if your rug was not made with vegetable dyes, because most synthetic dyes will last longer and you will have more years of enjoyment from your handmade Oriental rug.