12.

 THE BLACK CLOTH

This big and expensive Thornton Picard camera once belonged to a nobleman nearby, who took photography very serious. It was a semi-professional field view camera for glass plate negatives. Still in the early 1920's it was high tech. The excellent Euryplan lens made by Schulze & Billerbeck in Berlin was a precursor to most modern lenses.

Thornton's own time-controlled roller blind (curtain) shutter of opaque rubberized fabric had a very good reputation. The sensitiveness of glass plates had increased considerably over the years. This "Time and instantaneous"- shutter driven by a spring motor had to be wound up before use. Then it operated on the same principle as an old fashion window blind, but with speeds down to 1/80 sec.

Upside down? Yes the "display" worked that way in those days. A simple optic principle.
To examine the scenery on the ground glass, the lens had to be opened to its widest aperture. But still the image was not very bright. So you had to cover the edges and your head with a black cloth to eliminate all unwanted rear light sources. That made it possible to adjust focus correctly and compose the picture.

Then the ground glass would be turned up. It was replaced by a large wooden box containing the light sensitive glass plate. Well into the adjusted dark camera the lid of the plate magazine was drawn out and the sensitive plate could be exposed.

Note the comparison to the size of an A4 sheet of paper underneath  this negative! After developing this glass negative you could make perfect photographic copies on contact paper.  The picture size was not less than 18x24 cm and might fit an entire side of a normal book.

Books with pictures of foreign places were popular in those days before today's communications had been developed.