Abrash is color change in the face yarns of a rug due to differences in wool, dye lots or mordants used in the dying process. The color change occurs in straight lines across the width of the rug, left to right, along a row of knots and parallel to a weft yarn. Close observation at the back clearly shows the color change along a row of knots. Color change due to other reasons such as fading are irregular and follow no particular pattern.
Abrash can vary from subtle differences in shade to dramatic differences in color. Subtle abrash can be obscured by soil and becomes more apparent after cleaning, but a quick look at the back will confirm abrash.
Abrash is a characteristic of hand-woven textiles and does not, in itself, increase or decrease the value. In fact, some manufacturers of both hand and machine-made rugs intentionally weave abrash into their rugs. Abrash can enhance the beauty and desirability of a rug. Many modern rugs are woven intentionally with abrash. As in older, traditional rugs, the abrash can be subtle or quite obvious
Color Variation Due To The MIx Of Wool Used
Color variation in the face yarns can be a result of the type of wool used. The Afghan traders call it ‘Ghazni’ wool named after a trading town on the main road half way between Kabul and Khandahar. The perdyed wool is a mix of ivory and either gray or ginger colored fleece that is carded, spun and plied together to form a variegated/multi-colored natural yarn. These yarns are then dyed a single shade but the outcome is not a solid, uniform color.
Color Variation Due To Uneven Dye Absorption
Another cause of color variation is uneven dye absorption due to irregularities in spin (tighter and looser twists). When dipped into the dye vat, not all of the yarn is exposed to the dye and areas remain undyed or only slightly tinted. An example of this is similar to the process used to make tie-dye shirts.
Color variation can also be a factor of how densely the dye pot is filled with yarn and how often it is stirred in the dyeing process. Machine spun yarns tend to take dye more evenly which is why they are often less ‘interesting’ looking.
All content in this post comes directly from Rug Facts - Copyright 2016 Master Rug Cleaner