I like tracing sketches and making line art using a vector program like Inkscape. However, we can also create beautiful line arts using GIMP just like what others do with Photoshop.
GIMP has powerful Bezier tool that is both flexible and easy to use. With such flexibility, you can add, edit, and arrange your path on the fly. You can also create multiple paths at the same time.
Below, I’ll list several tutorials that uses GIMP in creating line art.
Lineart tutorial for GIMP
A DeviantArt tutorial by ~pheona where she shared her techniques in making line arts.
Using the Gimp: Lineart by ~saphiremomo
Saphiremomo used Stroke Path method in creating her line arts. She also shared several tips, tricks, and warnings.
How to do lineart with Gimp
This video shows a technique where Emulate Brush Dynamics was used to create the lineart effect
More tutorials to come..