Let’s see how we can make a digital slide duplicator for less than 10€ and using recycled materials. For that we will need a certain amount of skill, patience, meticulousness, and a Dremel to cut, adjust, drill, abrade, polish...
Digital duplication of slides or negative film is a good alternative to scanners, especially if you have the following studio equipment: a flash, a macro bellows and a digital camera. This post focuses on medium format Hasselblad V digital cameras with a digital back. The Hasselblad macro bellows (3040517) had this module long before the digital backs. It is hard to find it second hand, so you might as well make it yourself using an aluminium rod and an old film holder of an enlarger or a scanner, a white plexiglass plate, screws and magnets. By flashing the film, you can solve the problem of stray light without the need for the compendium bellows supporting the film holder. The flash generates a stable colour temperature and allows you to use a low sensitivity for better definition and a small opening of the diaphragm for a better depth of field: (ISO 50 at f/22).
Simply readjust the film holder to slide it onto the rod that fits into the hole in the bellows rail. Fit a white plexiglass to have a diffuse light. The film holder can slide on the rod. I opted for a fixed distance which allows me to have a little margin on the edges to rotate the scanned image in post-production if it is not perfectly straight. I can generate files measuring 45 cm x 45 cm in 300DPI. All colour adjustments are managed by the acquisition software of the digital back. I used here Capture One.
The aluminium rod is blocked by a small plug on its end which also maintains a good parallelism between the three planes: “As long as the three planes are parallel, the sharpness of the whole image is assured” - Scheimpflug principle. I opted for a film holder with a magnetic closure made with two magnets. The film is plated and perfectly flat. It's quick to set up and easy to adjust.
In conclusion, the result is quite good, largely equivalent to high-end flatbed scanners. On the other hand, it is a little bit inferior to that of a Hasselblad/Imacon scanner. This could be the subject of a future post.