I recently dropped off 4 rolls of film, but my download link only contains images for 3 of the rolls.

This occurs most often when one of the rolls in your order did not contain any scannable frames due to over-exposure, under-exposure, or camera advance malfunctions. When you come to pick up your negatives; we recommend using the light table in our lobby to look for such indications. Very dark film has been overexposed, very pale/transparent film is underexposed.  If there are viable frames that we missed for some reason, we will gladly re-scan your film.