Interesting find - a first. It looks like a thrips, a very small (1mm or so) insect. The size might explain how it got involved in the printing process. The brown glob at the posterior end is bug poop

, forced out of the poor critter as it got squished between a glass plate and the film during the scanning process.

image from http://sacs.cpes.peachnet.edu

EDIT: I added an image of a thrips alongside for comparison - if anybody cares.

EDIT: Thrips is the singular and plural - like fish, sheep or deer.

(I just found this out from an article in Google Sightseeing which referenced this article) Wikipedia - thrips