J E Wilson says:

I mix a 1 to 1 ratio in a very small amount to start, apply it, wait for it to dry and see the results. Most of the time I go from 1 to 1 ratio to a 3 to 1 – 3 parts india ink and apply it over the 1st application not covering the complete area to give it some depth. It really depends on the end result that you want. It is easier to add more ink than more alcohol to get the desired results. Hope this helps.