Inside a 35mm film camera, raised rails 24mm apart support the film between guide rails which in turn support the sprung pressure plate which when the camera back is closed hold the film flat while allowing just enough space for it to be wound on between exposures.
I have ten glass microscope slides that were coated with SE1 Emulsion left-over from large format glass plate preparation last July. The 1mm thick slides measure 75mm x 25mm and I decided to make an adapter that would enable me to expose them in a 35mm camera.
There were two main problems to overcome: the 25mm wide slides would have to be held centrally above the 24mm wide film-support rails without slipping out of position, and there would have to be a way of locating the slides in position in the dark. My solution was to make a tray from mountboard and stiff card using screws protruding from the camera as locating pins.
The microscope slides have at one end an opaque matt surface for writing on. It provides a textured area that enables identification by touch of which side is which. I have coated the textured side with emulsion and so this side will be placed down, i.e. facing towards the camera lens.
The mountboard was cut to the width of the film chamber and with rebates to locate the protruding screw-heads at the ends of the film transport guide rails. A hole to accommodate the glass slide was cut such that the emulsioned area of the slide would be located directly above the shutter mask. A piece of card cut to fit between the film guide rails and with an aperture just longer and wider than the shutter mask was fixed to the underside of the mountboard with double-sided adhesive tape.
The camera I have used is an Olympus OM1. I have other cameras but the layout in the back differs from one to another so my support tray will only fit the OM1. The reason for using the OM1 was that it takes the full length of the slide in position without placing it under undue stress and so reduces the risk of breaking the glass when the back is closed.