Monodiascope 6×13

The Monodi­as­cope, or mon­o­cle cham­bre noire, is a view­ing device designed for exam­in­ing panoram­ic pho­tographs, black-and-white or col­or. Although it is a monoc­u­lar device, it is insep­a­ra­bly asso­ci­at­ed with cam­eras used for tak­ing stereo or panoram­ic photographs.
One mod­el was spe­cial­ly designed for black-and-white pho­tographs. It is made of var­nished mahogany and fit­ted with a high-mag­ni­fi­ca­tion cylin­dri­cal lens, a ground-glass screen (for pho­tographs on glass), and a reflec­tor (for pho­tographs mount­ed on cardboard).
It was avail­able in 6x13 and 9x12 formats.
(from: Moulin­ier et al. His­toires de vision­neuses stéréo­scopiques français­es. Limo­ges, 2025, p. 109. Author’s translation.)