Richie,
Thanks for the nice comment. I use IsoPropyl alcohol from the grocery or drug store. typically I like the 90% or so, evaporates quickly. A few drops of india ink in a small cup. You can experiment, and add a few more until you get the color you want. I find it better to use several lighter colored coats instead of one heavy one. To be honest I don't have an exact mix, rather I have a small squirt bottle I mix it in, maybe 8 oz and then add the drops. I squirt into a plastic cut and use a small paint brush.