hi again colin
bummer, no darkroom ..
can you get a safelight red-bulb, and replace a room light with it ?
i do that on occasion, it works OK ...
...once you have the image you could get a hot plate and paper towel, cloth (to protect the paper)
and some bees wax or parafin and translucentize your negative.
the original salt prints were done on paper negatives, people have been waxing paper
negatives since around the same time ...
it might be something to think about if the blue filter doesn't work
if you coat your own with liquid emulsion it is pretty slow ..
i use butcher paper for my paper negatives, it is plentiful and CHEAP ( and THIN ) ...
can't say how archival it is though ...
good luck !