In the meantime, I got impatient and did a bit of an experiment using the liquid stuff from Michael's.
The challenge with using the liquid is there's no indication of the concentration. Is it mixed at a 2:1 ratio? 3:1 ratio? More? So, when my recipe calls for an ounce of gum arabic, I really have no way of knowing how much of the liquid to use. I ended up just eye-balling it, which is always a good way to go with chemistry. :)
I boiled down the indigo dye as instructed, then added my gum arabic. I then let it settle overnight so the indigo sediment settled. To get a decent coating without too much natural colour showing through I needed to do at least three layers, but I suspect that would vary by batch.
The colour is very much a blue, but when I apply it to the leather it gets very dark. You can see the blue tinge but it really depends on the light. In some light it looks like a dark grey or even black.
It also didn't bind at all to the leather. I was able to use a damp paper towel and almost completely wipe the colour off the leather, after it had dried. I was worried this might be a problem with this recipe, since every other recipe using indigo I've seen requires a strong chemical like lye to break down the indigo. It could also be because I used the liquid gum arabic, maybe it wasn't strong enough. From what I've read, the gum arabic is supposed to act like a glue and help bind the colour to the surface, so its certainly possible. I'll have to try again when I get the gum arabic powder.
Even if the next batch binds better to the leather, I'm not entirely sure I like the colour. It's just not "blue" enough in my books. There are a number of other recipes in the book for blue, including one that calls it "light blue", so I may need to keep experimenting.
|Me waiting for the watched pot of indigo to boil|
|This is the finished dye. You can see the blue on the glass is pretty nice.|
|In the light of the flash the dye looks black-ish but in normal light it is a dark blue.|