There are lots of different folding cameras for 9x12 glass plates from the beginning of the 20th century.
Popular examples are the Voigtländer Avus or Bergheil cameras as well as Ernemann, Zeiss ICA, Steinheil, but there are lots of different brands and builds which are quite similar.
In rare cases you will have a clean and working camera, an intact ground glass and the right metal cassettes and the often missing (and thus quite rare) inlays for sheet film in the 9x12cm format.
So you have your camera mechanics working, the lens is clean, the shutter is firing at correct speeds, but you are either missing the ground glass insert or cassettes with sheet film inlays?
Read on, because you could switch over to my international back for standard 4x5 inch (or 9x12cm) cassettes, including a fitting ground glass back.
Your camera should have rails of the "Normalfalz" type, typically found at Voigtländer cameras, but IIRC also on AGFA or Zeiss Cameras.
Some manufacturers used other rail geometries - in this case you would have to create a customized adapter plate..
Parts to print:
1x adapter plate (this plate slides into the metal rails on the camera's back)
1x cassette holder (glue it to the adapter plate)
1x cassette holder top (this is optional)
1x ground glass frame
2x ground glass holders
3rd party parts:
1x 9x12cm ground glass
4x 3x12mm screws
2x rubber rings
- fitting the cassette holder to the adapter plate may require a little bit sanding/filing
- mount the ground glass with the matte side down; when printed correctly, we have the "official" measurements as for standard cassettes. In comparison to the standard ground glass, my increases the distance to the lens a little bit (about 5-6mm)
- if you want to work with the focusing scale (on the focusing rails), you will have to adjust it to the new film plane
Update 2019-03-02: updated the ground glass holder, the original holder didn't have enough tension to hold down the ground glass.
use your preferred one PLA
I'd recommend different settings for the different printed parts, reflecting their specific requirements regarding stability (but also optimizing printing time and amount of filament)
adapter plate: 0.1mm layers, 100% infill
cassette holder: 01mm layers, 66% infill
cassette holder top: 0.15mm layers, 66 % infill
ground glass frame: 0.15mm layers, 20% infill
ground glass holders: 0.1mm layers, 100% infill
Step 1 cleaning up the edges
use a little file or sanding paper to clean up the edges of the printed parts
Step 2 check the adapter plate
check if the adapter plate properly fits your camera's back. It should slide into the rails smoothly.
Step 3 fitting adapter plate and cassette holder
I worked with quite tight measurements, so it might be necessary to work on the cassette holder to fit it to the adapterplate
Step 4 glueing adapter plate and cassette holder
use an appropriate plastics glue like Uhu Allplast. Use a Q-Tip to put the glue equally and thin onto the adapter plate. Put the cassette holder onto it and make sure it is flat down on the adapter plate. Check the edges and remove superfluos glue before it hardenes.
Put some weight on the cassette holder.