One of the hard things I have discovered in painting digitally is doing fine detailed straight lines from drawings. I stopped using the reference drawing as a guide for doing the work on the ship because the reference lines were too thick to see what I was painting under them if it is a layer above and not much help if it is below. Also, to better achieve the straight lines of all the aztec designs in the model, I have had to go to 400% magnification where normally I am working at 50%. Still I am correcting line angles and dropping back to 50% magnification to see the overall effect. So much work.