I heard on Woman’s Hour recently that red onion skins give green. I thought that was worth a go. Onion skins are very light, and you hear tales of people getting their friends and neighbours to save all theirs to go into the dye pot. As most people are dying enough fibre to make a garment or a quilt, while I’m only wanting to dye a silk scarf, I thought it was worth a go.
One supper from a Nadiya Hussain red onion recipe gave me more than I needed, in fact I had enough for two. I scrunched up both scarves, and put rubber bands round the bundle for one to get a marbled effect, and on the other I put some clothes pegs to give a random resist pattern.
The dye bath was pretty much the same colour as the skins that went in, but the result was a definite old gold, as so many natural dye stuffs yield. It is a nice colour, and it is quite different from the burnt orange I got with white onion skins.
So I wondered whether it was a mistake to use mordanted fabric. I just reached for the basket of alum mordanted scarves waiting to be processed, forgetting that white onion skins don’t need a mordant, so probably the red don’t either. The result was much more like the colour of a red onion.
But not green. And it proves that changing the mordant changes the result. But I didn’t have anything mordanted with another chemical handy. What else might change the dye colour? Acidity.
There was quite a lot of colour left in the second due bath, so I got out the ph indicator paper, and found that it was neutral. So I split it into two bowls, and added vinegar to one to make it acidic, and bicarbonate of soda to the other to make it alkali. Nothing terribly scientific, just enough of each to get the ph to 8 and 3.
So here are the results of the red onion experiments so far. From left to right, we have:
- the two alum mordanted,
- the exhaust dye bath from the one on the left, with white vinegar added,
- and the other half of the exhaust due bath, with bicarbonate of soda added.
So still no green. I’m guessing the bicarbonate of soda had no effect, as the paler colour is probably the result of reusing the dye. Of course, what I should have done is to split the dye bath into three, so I had an un-adapted “control”, but I didn’t think of that in time.
So now the experiment is on pause until I have more red onion skins.