I have to agree with Ryuji. That is why I have concentrated on Azo paper, and a Kodabromide/Brovira paper. But, OTOH, there is such a thing as being prepared.

That is why I am developing a simple film emulision with a 40s look or thereabouts, to be ready for those who want such a film and also to keep the technology alive. I am also doing it because it can be done, and done simply in a darkroom.

PE