After the pencil drawings are completed, the next phase of comic creation is called inking.
Here you can see the artist is outlining the key forms and dropping pull out feathering as he goes.
Core shadows are also outlined and then filled out with a paint brush.
You can see the ink is being applied directly to the penciled page. This is a destructive style of inking, where once you ink the pencils are covered forever. This method is dependent on your team and is a choice.