It's all relative, Michael. That's why old school portrait photographers liked 11x14 cameras - it was so easy to do the smudge or dye work
directly on the film itself. It's easy to do on 8x10 too. But try it on something like a little 645 neg, or even on an attached mylar sheet with
diffusion, and things get rather problematic. It can be done, but it's only a matter of time till the folks in the white coats haul you off to a
padded cell. What is unfortunate is that so many basic methods of work have simply been forgotten. If you browse used book stores, you
can sometimes come up with old Kodak darkroom or graphics arts manuals that show the traditional tricks. Masking can be either as simple or
as complex as one wishes, just like printing itself.