Light Box v2

This is an improved light box design for DSLR based film digitization over the one detailed in Improving Film Scans. I built it a year ago and though to write something about it as this is common technique to digitize film nowadays.

The previous attempt was made using high CRI LED light strips with the goal to improve digitization of color negatives (together with negative lab pro for post processing). Unfortunately the results were still a bit of hit and miss so I decided to make another attempt using a camera flash unit instead of LED strips. Camera flashes output light for accurate color reproduction so should rule out the light source as the culprit behind any unsatisfactory result.

Here is a photo of the digitization setup.

The box is custom made for the Godox AD100Pro flash unit that is radio triggered from the camera. The flash has a LED modeling light that is used on a low setting to back-light the film as a focusing aid.

This time I made the box using MDF which is more stable than plywood. The design is much simpler and at the same time with better tolerances. I really loathe making blueprints but I think you’ll get the idea from the construction gallery. The MDF and its grooves were cut using a circular saw with an ad hoc fence. Dimensions were fine tuned using a hand plane before glue up.

In the photos you’ll see some construction adhesive being used. The idea was that this should bond the top Plexiglas sheet to the MDF but in the end this did not work. I used double sided tape instead. Had I known this beforehand, I would have glued the MDF using regular wood glue.

As before, aluminum foil tape is used as the reflector inside the box and opal white Plexiglas sheets as light diffusers. This time, three layers of Plexiglass were used instead of two because the flash enters the box from the side which is sub optimal for even lighting. It turned out that using the flash unit on its max zoom level produce the best result. For 135 format film the result is perfectly adequate. For 120 format film (645) the result is probably good enough in practice but uneven lighting can be observed in test shots with blank film.

The ergonomics of the new digitization light box is much better than the previous one. Because the camera can now use the flash sync shutter speed, it’s possible to work with subdued interior lighting. The flash overpowers any such light. As for the result, I can’t really say that it’s better. I’ve not really tried to quantify it properly so I dare not say. The color balance of color negatives is still hit and miss but now I can blame negative lab pro with good conscience. Perhaps it will improve in the future, or some other post processing software surfaces. I’m mostly happy with digitized black and white negatives (as I was before). Some examples can be found in the sample gallery.

Some final words about working with MDF. Make sure to wear a dust mask when cutting MDF. It’s not good for your health to breath it in. This goes for regular wood as well but MDF is worse by containing resins.

Published: 2023-01-03