Abstract: Pure-blue images are obtained by developing a diazo photographic material containing a photosensitive diazonium compound in the presence of a coupler capable of forming a blue dye by coupling with the photosensitive diazonium compound, the coupler being represented by the general formula ##STR1## wherein R.sub.1 represents ##STR2## (wherein R.sub.2 and R.sub.3 each represents a hydrogen atom, a halogen atom or an alkyl group having 1-4 carbon atoms), --COR.sub.4 (wherein R.sub.4 represents an alkyl group having 1-4 carbon atoms or substituted or unsubstituted phenyl group, or ##STR3## (WHEREIN N REPRESENTS 1 OR 2) OR BY THE GENERAL FORMULA ##STR4## wherein R.sub.5 represents a hydrogen atom, an alkyl group having 1-4 carbon atoms or ##STR5## (WHEREIN N REPRESENTS 1 OR 2).

Abstract: A film cassette comprising an outer case containing monosheets therein and having a front wall defining an opening, through which said monosheets may be exposed, an end wall defining a removal passage, through which said exposed monosheets may pass, and another end wall defining an insertion passage, and a lightproof protective board, which is locatable in a foremost position in said cassette to protect said monosheets from exposure to light through said front opening, is removable from said cassette through said removal passage, and is insertable into said foremost position through said insertion passage.

Abstract: A heat developable light-sensitive material having increased transparency comprising, on a support, an organic silver salt, a light-sensitive silver halide, a reducing agent, a binder and an overcoat layer consisting essentially of a polymer.