A few weeks ago I tried dip dyeing in the indigo vat at Morley College. To put it bluntly, it was not a huge success. I now know that this was probably because the vat was too strong to get really pale blues – and I was leaving the fabric in too long.
Also, because we are requested to keep the lid on the vat during dyeing to prevent the indigo oxidising, I had to rig up a kind of Heath-Robinson contraption to try to lower the calico into the vat bit by bit over 10 minutes. You can see in the piece on the right in the photo below where the fabric was suspended by the upper corners that never got immersed in the vat!
The piece on the left was dip dyed in my home vat. Because it’s been six days since I started the vat, my kitchen where the vat is kept is very cold, and the vat was very dilute to start with, my test swatch came out very pale, even after one minute.
So I warmed up the vat, added tiny amounts of indigo, hydros and washing soda, and tried the dip dye. Much better!