I have a hydrosulphite indigo vat outside the entrance to my house. It is too cold in the middle of winter and I simply stir it a few days a week to keep in touch. It ices over when the temperature drops below minus 5. I'll dip in something that needs a single quick dip but it is next to impossible to spend any length of time in the cold dying. A few students have been coming to class and working on shibori the past few months. They couldn't wait for spring to dye their work so I put a tropical fish tank heater inside a tube of water and submerged it in the indigo to warm it up. We dyed yesterday outside on a freakishly warm day. The snow was melting and it was a muddy squishy mess...
But the joy of indigo dying took aver and the focus was on the dye and not our freezing feet.
Using a hydro-sulphate vat everyday in the warmer weather I sense what the pH is and how much pigment is left and how much oxygen has been introduced into the dye bath. Starting the season yesterday involved some guesswork to get the indigo in top condition after it sleeping for several months. The pH had dropped substantially and I added 150 grams of slaked lime and about 100 grams of hydro-sulphate and 100 grams of indigo powder. The condition was perfect and aside from terrifyingly cold rinse water from the outside tap the day went well.
These pictures of indigo drips on melting snow sum up the day.
