This week: A step by step on how to avoid indigo spots from the dye vat.
Each week, we are emailed with questions from our natural dye community asking simple and complex questions that we thought might be worth sharing. Here are a handful from this week answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors:
I keep getting very dark- ink-like spots on some of pieces. There seems to be no rhyme or reason to it… and of course it ruins the dye piece. Do you have any advice on how to avoid these dark spots? I followed all the instructions and even brought the dye pot to a high heat to and stirred a lot to make sure no sediment was left. A quick dip with the fabric moving constantly still produces these marks.
If you are getting tiny dark pinpoint spots, that might be undissolved dye. If you see undissolved dye or sediment, add more water to your container and you can also add a small amount (1/8th teaspoon or less) of soda ash, which will deepen the purple shade somewhat. You can also filter or strain the dye liquid prior to adding it to the pot.
If you are getting dark, irregular blotches, that can be a result of uneven mordanting, irregular handling of the goods in the dye pot or starting your dye pot too hot. We recommend for the dye process:
1. Make sure dye is dissolved completely and stir into dye pot. Use enough water so the dye is dissolved.
2. Enter in scoured and mordanted goods while dye pot is cold. Use a large enough pot so your goods move freely.
3. Saturate goods, moving constantly for 15 minutes in the cold or lukewarm dye pot.
4. Slowly bring up the heat, moving constantly. This is critical for evenly dyed goods. You need to keep the goods moving while the dye strikes into the fabric.
5. Hold at temperature for 45 minutes moving less often but don’t let the fabrics “cook” in one place.
Keep in mind that different fabrics (open weave vs. tightly woven, light vs. heavy knits) will behave differently in the dye process. Lighter and more open fabrics will dye more evenly. A quick dip in a hot dye pot will not avoid unevenness.
Another area where uneven dyeing commonly occurs is if the mordant process resulted in uneven mordanting. Make sure your fabrics aren’t bubbling up and leaving air pockets and that you move the fabrics in the dye pot or container while mordanting.