Traditionally used by draftsmen and architects, Drafting Film is gaining popularity with artists.
Grafix Drafting Film comes in a variety of thicknesses, in sheets and rolls. I bought a .005 roll from a local art store, and have tried sheets of .003 and .007. I favour the rolls. Drafting Film is very sensitive to fingerprints (and tape!), so to prevent fingerprint-created flaws emerging in my shaded areas, I wear cotton gloves to unroll and cut the film to specified dimensions. I always draw with my hand resting on a sheet of tracing paper to protect my drawing surface.
My understanding is that DuraLar is made by the same company, but it has a slicker feel and doesn’t accept as many layers (which is really saying something, because I find that Grafix Drafting Film saturates quickly!). I’ve seen DuraLar referred to as a ‘student grade’ version of Drafting Film, but there are artists who swear by it, and use it exclusively. I discovered Drafting Film in 2022, and now use it for most of my portrait work.