Last night, I pondered on the possibility to construct curved filmholders for a new pinhole camera I have in mind to make. The one substantial obstacle I see is the light barrier any filmholder must have when the dark slide is taken out for exposure. Any proposals of how to make? One more question, maybe: does anyone have a clue from where to get this completely light-tight black paper placed between sheet films in the boxes of some brands? Getting some larger sheets of this would be quite helpful for the filmholder design I have in mind.