Hardened high-contrast photographic silver chloride emulsions and method of processing

Claim 1

IN THE PREPARATION OF A HALF-TONE PATTERN BY EXPOSING A DRIED, THIN PHOTOGRAPHIC SILVER HALIDE EMULSION LAYER ON A PHOTOGRAPHIC SUPPORT TO A HALF-TONE IMAGE AND DEVELOPING THE RESULTING EXPOSED SILVER HALIDE EMULSION LAYER WITH A PHOTOGRAPHIC AQUEOUS DEVELOPER, THE IMPROVEMENT WHICH COMPRISES EMPLOYING A HIGH-CONTRAST PHOTOGRAPHIC GELATINO-SILVER HALIDE EMULSION LAYER CONTAINING AT LEAST 6 MG. PER SQUARE FOOT OF UNCOMBINED FORMALDEHYDE, THE QUANTITY OF FORMALDEHYDE PRESENT IN SAID SILVER HALIDE EMULSION LAYER PRIOR TO DRYING BEING BETWEEN ABOUT 0.1 AND 2.0 MOLE PER MOLE OF SILVER HALIDE, SAID SILVER HALIDE EMULSION CONTAINING AT LEAST 70 MOLE PERCENT SILVER CHLORIDE, AND A PHOTOGRAPHIC AQUEOUS DEVELOPER HAVING A PH OF AT LEAST 9.0 AND CONTAINING A HYDROQUINONE AS THE ACTIVE DEVELOPING AGENT AND AT LEAST 0.01 MOLAR OF SULFITE ION.