FEEDBACK FRIDAY: This Week in Natural Dye Questions

This week: What kind of dye pots should you use, do liquid dyes need a mordant and how to shift color with iron

Every week, we are emailed with questions from our natural dye community asking simple and complex questions that we thought might be worth sharing. Of course, all of your burning questions are answered by natural dyer in chief, Kathy Hattori, Founder of Botanical Colors.

I have been following your Instagram page for some time now and often link into the Feedback Friday questions….most enlightening! I am wondering what grade/ brand of stainless steel pots you use for indigo dyeing? I have ruined 2 pots making organic indigo vats (banana) – the stainless steel has been corroded off the inside of the pot. The pH was 11 to 11.5.

Stainless steel is normally impervious to alkalinity, so if the inside of your pot is getting corroded, it is probably an aluminum pot, or very thin stainless. Stainless should have a rating of 18/8 or 18/10. We have pots like this and have used them without problems for nearly 30 years. Typical brands are Vollrath, Tramontina (usually a good value). The pot will be pretty heavy, and not thin and shiny, or matte and very light.

Can I use your liquid dyes with alum mordants?
Yes, the dyes work with alum mordants such as aluminum potassium sulfate and aluminum acetate. You may see different color results depending on the mordant that you use.

How do I use iron for color shifting a color like logwood darker?

We have lots of info on that here but here’s some info from that page:

1. Fill a dye pot with enough water to hold fibers, and add iron solution and stir well.
2. Add fibers, rotating often for the first 15-20 minutes, then make sure they are fully submerged in the iron solution
3. Heat the iron mordant bath to 130°F (55°C) and hold for 30 minutes, stirring carefully and constantly to avoid streaks.
4. Remove from heat, let cool to handle easily and rinse fibers in cool water.
5. For color shifting, immerse your fibers in the cold iron bath after you have first dyed your fibersa base color. Watch your fiber or yarn and remove it when the iron has shifted to the color you desire. This may take only a few minutes, so watch carefully, and your iron bath temperature
may still be cold or barely warm, as this reaction works fast. Cool the fibers, then rinse in cool water. If you want very dark grayed shades, allow the fibers to remain in the bath and bring the temperature to 130°F (55°C), removing when it is the shade you desire. Cotton, linen and hemp
will tolerate higher dye bath temperatures, and you can bring those to 180°F (82°C) for darker shades.

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