The finish(Tru-Oil) was added on top of the drawings. India ink is the most permanent ink I've found to write on bows. Having an appropriate surface for the ink is important. Bare wood usually causes the ink to run or bleed. I usually spray satin poly over where I want to write and let that cure out good, then write with the india ink. Lert the ink dry completely and add a thin coat or two of Tru Oil over the writing. When that dries I give it a quick spray of the satin poly to cut the shine.