Since it usually takes me a long while to actually make line art, I was thinking of a quicker way to make line art & finally found a way in GIMP. However these two friends of mine asked me how I made the line art. This tutorial finally reveals the secret.
I tried to upload the file in the original size but Deviant Art rejected it because it's "too big".
Forgive me if the text looks too small because I had to resize the tutorial image.
Hope this tutorial helps you guys.
Sonic drawing picture drawn by me (Sonic belongs to Sega & Sonic Team).