Red window

In 1892 the red window was introduced by the Boston Camera Manufacturing Company as a means to control film advance of paper-backed rollfilm in the No. 2 Bulls-Eye camera. Later this became the film advance control device of nearly all cameras for the popular rollfilm formats 127 (4cm) , 120 and 620 (6cm). The appeareance of the next exposure number in the window means that the film is advanced enough for not achieving overlapping exposures.

Looking behind a box camera's door: the number visible through the red window is one of the exposure numbers of the eight possible 6×9cm exposures. Other number rows are visible through exp. counting windows of cameras with smaller frame format.

Glossary Terms