Recently my social media has been filled with people using salt to extract colour from fresh indigo leaves. I tried this method with my woad plant last year with some less than exiting results, but not one to shy away from a failed attempt I wanted to have another go with indigo.
I collected a small amount of indigo (Persicaria Tinctoria) leaves (58 grams) and added approx. two table spoons of salt into a bowl with some un mordanted wet linen, cotton and silk and started rubbing them all vigorously together.
That is the long and short of it. A whole lot of rubbing. Last year with my woad leaves, I only worked the fibres with the leaves once and managed to get a very light mint green shade, which has unfortunately faded to nothing. With the indigo leaves, I worked the fibres 4 times, letting them oxidise and rest between rubs and the colours were much deeper. I realize indigo generally gives stronger colours than woad, but I am now interested in trying woad leaves again.
I left the fibres to dry out for about and hour after my last rub and then washed them in some PH neutral detergent and left them to dry.
I am pretty pleased with the results, especially how well the plant fibres took the colour. I have mainly seen this method used on silk and it works beautifully on that so I am expecting the plant fibres to fade a little. I am planning to harvest my leaves again tomorrow, for another vat. When the plants have picked up again, Id like to try the salt rub again with mordanted fibres to see if the colours are different.