Just to prove I’m still playing with indigo, although I’ve had less time than I thought I would.
If you’ve only got a few leaves, try leaf prints.
This is Japanese indigo. The technique also works for woad leaves, although the print is fainter than this, at least from my plants; ‘true’ indigo should also work. I am astonished by how much of the leaf structure can be captured by this technique. (The skulls were printed by rubbing fresh leaves through a stencil; I have to post this, too!)
Leaf printing seems to work best on finer fabrics like this silk; I tried it on a heavier cotton/light canvas, and the juice didn’t penetrate far enough to make a good print.
Take a leaf, put it on the fabric, cover it with a piece of clear plastic/heavy cellophane (I used a piece from a packet of oat bran). Take a dessert spoon and hammer the leaf with the bowl of the spoon through the plastic; try to make sure you cover (damage?) the entire leaf area. I think this breaks the cells to release the juice. Then put a dab of washing-up liquid on the plastic to act as a lubricant (don’t get it on the cloth) and ‘polish’ the leaf through the plastic, using lots of pressure. Too much and you can see the leaf squash into mush that obscures the detail; too little and the juice isn’t pressed into the fabric. Practice. Have fun!