[Kyousuke]

Add some tracing paper over the original and ink it to make a duplicate to keep the original safe. it's also good practice if you dont know how to ink. just be sure to take it off before inking or else you risk the ink seeping through to the other side and onto the original. you could also darken the lines by using led pencil, just don't push down on it or it'll leave visible lines on it that can be seen from the other side.