Although with the scanner you don't need to but have you tried photographing them ? you need some sort of light box I've done a B&W negative and inverted it and tweaked it a bit it was reasonable

No, I haven't, though we occasionally did something like that where I worked (from microfilm, as it happens). I've owned a flatbed scanner that can do slides and film since 2004, and this scanner for about five years, so there hasn't been much reason to try.

MAGIC BOX

It is.