The present document discloses a method of determining thickness of a wet film, in particular of microfibrillated cellulose. The method comprises conveying said film (20) in a wet state on a conveyor (10) having a conveyor width, the wet film having a film width which is less than the conveyor width, providing a laser projection (1511) across a film edge, acquiring a series of images, each depicting an area of the conveyor, wherein the laser projection, a portion of the film and a portion of an exposed conveyor surface are visible, and using at least some of said images to determine at least one of a film thickness and a film thickness distribution across the film width. The document also discloses a method of forming a film, in particular a microfibrillated cellulose film, and a device for producing such film.