If you are still unsure if your carpet is vegetable dyed after reading
this post, bring photographs of your rug to our RugRag Forum!
In using the Rug Estimator Pro, if you don't know for sure about the dyes in your rug, select "No/Don't Know." Newer rugs are considered by many to be vegetable dyed if in fact 85% or more of the dyed wool is veggie dyed. Certain colors are not easily attained by natural dyes. For purposes of the Rug Estimator Tool, only use this selection if you
are 100% certain that your rug is made with vegetable dyes or natural
dyes. If the rug appears to have no dyes (e.g. only brown, ivory or
lighter colored wools), select "no/don't know".
About natural dyes
Natural dyes come from four main sources: vegetables, fruits, plants and insects.
It was not until the 1860's that synthetic dyes were introduced to rugs and carpets. These dyes were inconsistent, and were banned for use in Persia from around 1870 through 1905 as they were deemed inferior. There were some select groups that continued to use synthetic dyes, although it would not be until the 2nd quarter 20th century that well developed synthetic dyes could acheive satisfactory and proven results.
What do Vegetable or Natural Dyes mean to you
Unless you are in the market for an investment grade rug or are going "green" there is no point to assessing dyes. If the rug is newer, there's no exact way to determine the true source of dyes. You should make your rug purchase based on your desire for design, aesthetics, overall appeal, and if you are green, responsible living.
Initial negative reaction to synthetic dyes was well rooted back in the late 1800's. However, the stigma for which is attached to them has carried many decades too long. There is much debate about which is the superior dyeing - natural or synthetic. However, there are multiple factors which influence what is considered superior and inferior. Both natural dye and chemical dyes may run, and both can be colorfast - and much of this has to do with the mordants which are used to fix the dyes and the initial quality. Natural dyes tend to be more labor intensive and require a much more intimate technique. In antique rugs or carpets pre-1920's vintage, they are highly preferred. Nonetheless, natural dyes are now generally more costly.
Truly the best and most accurate way to check for your rugs type of dye is to purchase from a reputable dealer, and ask him outright what types of dyes are used. Unless they are the manufacturer or importer, they may not even know. Less reputable sellers may claim a rug to be natural dyed even if the rug only has a fraction of a percent veggie dye or even none at all. Some chemical dyes can mimic almost identically the appearance of natural dyes, and often they will be passed as such.