Cross-Dyeing
May 2023
The cross-dye technique requires a fabric or garment composed of multiple fiber types (e.g., wool and linen) and exploits each fiber’s unique affinity for dye to create multicolor effects. This can be accomplished with synthetic or natural fibers and dyes; however, the possible range of effects becomes limited when using only natural fibers and dyes.
In our February 2023 post, we explored the simplest form of cross-dyeing with natural dyes and fibers. There, we used a wool/hemp/silk blend to highlight how different mordant methods affect the result when using only one dye (lac). This form of cross-dyeing, simply relying on different fiber types in a fabric, tends to create subtler effects that can appear two-toned or a bit more nuanced when preventing the hemp fibers from taking any dye, such as with the one-bath acid dye.
Another method, which we’re not exploring here, is combining a direct dye and a mordant dye in the same dye bath when dyeing a fabric containing protein and cellulose fibers that has been mordanted for cellulose. The hope here is that the direct dye will primarily attach to the protein fibers and the mordant dye primarily to the cellulose fibers. We’ve tried this once with cutch, a direct dye, and madder, a mordant dye, and obtained a yellowish brown on the protein fibers and a pinkish brown on the cellulose fibers.
Here, however, we’re focusing on using indigo as an underdye with a one-bath acid overdye to obtain two distinct hues on our wool/hemp/silk fabric. The basis for this cross-dye technique relies on indigos greater affinity for cellulose fibers and one-bath acid dyes, which dye only protein fibers. Below you’ll find the fabric (i) in its natural state, (ii) dyed with indigo, (iii) dyed with indigo and overdyed with lac, and (iv) dyed with indigo and overdyed with cutch.
Natural / Undyed
The fabric we used for this experiment comes from an Italian wool mill, Lanificio Bottoli. As part of its eco-friendly collection, this twill is composed of three undyed fibers: wool, hemp, and silk. The taupe yarn is pure wool, whereas the white yarn is 2-ply and composed of hemp and silk yarns.
Indigo
This swatch was dipped in our indigo vat once for ten minutes. We created a strong vat at 8 grams of indigo per liter of water, which is how we obtained such a saturated color after only one dip. Though we only used one dye, we still obtained a cross-dye result given indigos greater affinity for cellulose fibers and the wools natural taupe color. The hemp/silk yarn dyed a typical indigo blue, whereas the wool yarn turned a cool shade of gray.
Indigo Underdye + Lac One-Bath Acid Overdye
By far our favorite, this swatch highlights how two distinct hues can be achieved on a fabric with natural dyes. As with the above swatch, we dipped this in indigo once for ten minutes and then overdyed it with lac using the one-bath acid dye method. Because the one-bath acid dye method prevents cellulose fibers from taking any dye, the hemp fibers remained a true indigo blue. The wool and silk fibers, however, took the lac dye. The wool turned a deep burgundy, whereas the silk stayed a handful of shades lighter. If you look at the frayed ends closely, you can see how the hemp/silk yarn is really a 2-ply yarn with a hemp yarn (blue) and a silk yarn (burgundy) twisted together.
Indigo Underdye + Cutch One-Bath Acid Overdye
We dyed this swatch same as the one above but used cutch as the overdye. The results here are much more subdued but still multicolored. The hemp fibers remained blue. The wool and silk fibers, however, turned a similar shade of gray, which we didn’t anticipate. Typically, and without assists or modifiers, cutch yields a soft shade of cinnamon, and we would’ve expected a warmer, brownish color on top of the indigo underdye. But as always, dyeing is unpredictable, and regardless, the colors are beautiful.
Cross-dyeing brings an aspect to natural dyes that is often overlooked and one we love to explore and offer. An unfortunate truth is that this process, especially when using indigo as an underdye, is time and resource intensive. Currently, our Panelled-Pocket Short and Panelled-Pocket Jacket explore the easier side of cross-dyeing, i.e., using one dye on a fabric composed of both cellulose and protein fibers to create tonal effects. We hope in the future to offer the more complex side of cross-dyeing shown by the indigo underdye + lac or cutch one-bath acid overdye swatches.
