Film Flatness and Kiev 60
Let us now have a look at the situation in cameras with an additional pair of rails (or other device) to support the pressure plate at a definite distance from the film guide rails.
In the Kiev 60 we have a free space for film and paper of 0,5mm, which is more than film´s plus paper´s thickness of about max. 0,3mm. Therefore the film edges have much space and are not pressed, film lying flat on the pressure plate. But, the film´s distance from the lens is rather too big, so that in some cases a piece of self adhesive sheet material of 0,1 mm thickness sticked onto the plate is recommendable, upper and lower edge of the plate have to remain free, of course, otherwise the whole plate would be lifted.
Film Flatness and Exakta 66
In the Exakta 66 we have a similar construction, only that the space for the film (and paper in case of 120 type film) is not sufficient. Bending the plate´s lashes to increase the space can help to improve flatness and distance to the lens as well.