just make retina prints, in camera paper negative long exposure
without developer and don't bother fixing
you will have negatives and they will degrade very very fast
behind glass, maybe less time than without museum glass.
you can also contact print onto photopaper the same way ..
long exposures in the sun. the image will be stained on the paper
and VERY unstable. fixing them will turn your paper white ...

good luck !
john