As part of a mini project to build out an economical but effective film negative "scanning" solution, I've just ordered an interesting little product designed and manufactured here in the UK... the
EFH Essential Film Holder Kit.
Using interchangeable masks, the EFH is designed to hold 35mm or 120 film strips perfectly flat with minimal risk of scratching and contamination, whilst diffusing whatever light source is used to illuminate them from behind, so you can capture them with a digital camera. A typical setup comprises an LED light panel placed on the floor, the EFH - with film strip loaded - resting on top of the panel, and a tripod-mounted camera pointing down at the EFH, aligned as best as possible to capture the frame with minimal perspective distortion. Alternatively, a copy stand could be used in place of the tripod; and that's an option I'm seriously considering, as setup and alignment should be considerably easier.
I looked at various film holder products from companies such as Kaiser, Skier, Lomography and others, but this seems to be a more elegant and well-thought-through solution... plus it's not badly priced, at GBP £90 shipped (worldwide) for the 35mm + 120 kit, plus - optionally - another £30 for a set of additional 35mm + 120 masks that show the film sprockets and/or borders (I've ordered these too). Of course, you need to add a suitable light source for illumination, and I'm researching options for that. In a pinch, a smartphone or tablet will suffice, but a high-CRI 5000 - 5600K LED panel is a far better choice, especially for colour films.
Amateur Photographer magazine reviewed the EFH, and gave it five stars out of five. Since then a more refined version 3 has been released. Folks who've used it seem to be very impressed, so I'm hopeful it'll do the job nicely.
It's a small, family operation that manufacturers and sells this. They assemble each unit by hand, then test with film to ensure it's problem-free before shipping. Currently, it's taking them around three weeks from date of order to ship, so I have a little while to wait before I receive it; which is fine, as it'll be a few weeks before I'm in a position to test it...