Abstract: In an apparatus for exposing a strip of photographic positive paper to light shining through a strip of photographic negatives for producing latent photographic images, an adjustable length mask for defining the outline of each photographic image print on the positive paper strip. The mask, which overlies the positive paper strip, includes manually movable plates for adjusting the length of the mask opening. An automatically operated marker punch is mounted upon the mask, offset from the lighted print area, and includes a replaceable thin punch blade positioned to form a narrow slot in the paper at the lead edge of each separate print, which slot is later used to actuate a cutter mechanism for cutting apart the developed prints from the positive paper strip.