Epitaxially sensitized tabular grain emulsions containing speed/fog mercaptotetrazole enhancing addenda

The photographic element comprising at least one layer comprising a radiation-sensitive silver halide emulsion comprising

• silver halide tabular grains
• (a) having {111} major faces,
• (b) containing greater than 70 mole percent bromide, based on silver,
• (c) accounting for greater than 90 percent of total grain projected area,
• (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m.
• (e) exhibiting an average thickness of less than 0.07 .mu.m and
• (f) having latent image forming chemical sensitization sites on the surfaces of the tabular grains, and
• a spectral sensitizing dye adsorbed to the surfaces of the tabular grains,
• wherein the surface chemical sensitization sites include at least one chemically sensitized silver salt epitaxially located on less than 50 percent of the surface of said tabular grains and wherein said emulsion further comprises a mercapto compound represented by Formula III ##STR8## where M is H or Na and R.sup.1 is an aliphatic or aromatic radical containing up to 20 carbon atoms, and wherein said silver salt is predominantly located adjacent at least one of the edges and corners of the tabular grains.