Just playing around with silver, blue, and black inks in mixtures. Firstly, black lines painted on the paper, then varnished, then silver, then blue, all in various layers.
Looks ok, but nothing special.
For a second attempt, I tried varying from top-to-bottom the blue and black. This is quite pleasing:
The gradient here is great, although there is not much to this. Would be nice to have more structure. Sadly I think that both of these were thrown away, as I cannot find them any more…