Film Term:
The emulsion batch is the series of numbers on the film can that come after the emulsion type. When the film is made, each batch is given a number so that you can shoot a single sequence with one particular batch. Just as a suit where the pants and jacket were cut from different bolts of fabric might be a little off, a sequence shot with different emulsion batches might also be a little off. From one sequence to the next, of course, this doesn’t matter. (And the batches themselves have become more consistent in recent years, so mixing them is less of a sin nowadays.)
Glossary of Film Terms - http://homepage.newschool.edu/~schlemoj/film_courses/glossary_of_film_terms/
reprinted with permission