thinning your ink

i know how stupid this may sound to some of you other professionals, but i have forgotten how to thin ink thats starting to thinken .i remember that its equal parts of this and that but i dont remember what. I havent had to do it in years so when the time came (today) im completely at a loss .....any help would be greatly appreciated .......thanks in advance....brutal

I've used a couple of methods. When my ink gets think i usually set my self out a couple of large ink caps (#16) and in one i a very small amount of 99% rubbing alcohol, in the next i put a little more than the last, i then repeat that with original listerine, and then repeat with a distilled water. Then put you pigment in the ink caps and see what has worked the best. You may have to give your self a tattoo to see what has worked best.