The consumer films are typically what we think of with instant film. You press the shutter release button, a picture is pushed out the front of the camera and slowly an image appears on the film. The professional films are all peel-apart type films meant for medium format camera backs and larger portable "Land" cameras. With these films, you expose the film, then pull it through rollers which press all of the internal chemistry together and start the development process. After a set amount of time, you peel the paper positive off of the negative and you are left with a beautiful image.