Roll film

The opaque backing paper allows roll film to be loaded in daylight.

It is typically printed with frame number markings which can be viewed through a small red window at the rear of the camera.

In 1881 a farmer in Cambria, Wisconsin, Peter Houston, invented the first roll film camera.

His younger brother David, filed the patents for various components of Peter's camera.

[1] David Henderson Houston (born June 14, 1841; died May 6, 1906),[2] originally from Cambria, Wisconsin, patented the first holders for flexible roll film.

A spool of Fujifilm -brand type 120 negative roll film
Classic 120 negative roll film, manufactured by Agfa-Gevaert , with backing paper indicating total exposures available for 4.5×6, 6×6 and 6×9 cm camera film-frame sizes
Various brands of sealed 120 negative and transparency roll films