Radiographic elements with improved detective quantum efficiencies

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for absorbing radiation to which said emulsion layer units are responsive,
• CHARACTERIZED IN THAT each of said emulsion layer units
• (a) contain a polyalkylene oxide block copolymer selected to satisfy one of the formulae ##STR14## where LAO1 in each occurrence represents a terminal lipophilic alkylene oxide block unit,
• HAO2 in each occurrence presents a terminal hydrophilic alkylene oxide block unit,
• HAO1 represents a hydrophilic alkylene oxide block linking unit,
• LAO2 represents a lipophilic alkylene oxide block linking unit,
• each block linking unit constitutes from 4 to 96 percent of the block copolymer on a weight basis,
• the block copolymer S-I has a molecular weight of from 760 to less than 16,000, and
• the block copolymer S-II has a molecular weight of from 1,000 to 30,000 and
• (b) exhibit a coefficient of variations of less than 15 percent, based on their total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of from 0 to 5 mole percent chloride, from 0 to 5 mole percent iodide, and from 90 to 100 percent bromide, based on total silver.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and coated on said opposed major surfaces,
• emulsion layer units comprised of spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for absorbing radiation to which said emulsion layer units are responsive,
• CHARACTERIZED IN THAT each of said emulsion layer units
• (a) contain a polyalkylene oxide block copolymer selected to satisfy one of the formulae ##STR17## where LAO4 in each occurrence represents a terminal lipophilic alkylene oxide block unit,
• HAO3 in each occurrence presents a terminal hydrophilic alkylene oxide block unit,
• HOL represents a hydrophilic alkylene oxide block linking unit,
• LOL represents a lipophilic alkylene oxide block linking unit,
• z is 2, and
• z' is 1 or 2,
• each block linking unit constitutes from 4 to 96 percent of the block copolymer on a weight basis,
• the block copolymer S-III has a molecular weight of from 1,100 to 60,000, and
• the block copolymer S-IV has a molecular weight of from 1,100 to 50,000 and
• (b) exhibit a coefficient of variation of less than 15 percent, based on their total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of from 0 to 5 mole percent chloride, from 0 to 5 mole percent iodide, and from 90 to 100 mole percent bromide, based on total silver.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain in the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on their total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the total grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing at least 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 760 to 16,000 satisfying the formula:
• LAO1--HAO1--LAO1
• where
• LAO1 in each occurrence represents a terminal lipophilic alkylene oxide block unit containing at least six --CH(CH.sub.3)CH.sub.2 O-- repeating units and
• HAO1 represents a hydrophilic alkylene oxide block linking unit containing --CH.sub.2.sub.CH.sub.2 O-- repeating units forming 5 to 85 percent of the total surfactant molecular weight.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on their total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing less than 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 760 to 16,000 satisfying the formula:
• LAO1--HAO1--LAO1
• where
• LAO1 in each occurrence represents a terminal lipophilic alkylene oxide block unit containing at least six --CH(CH.sub.3)CH.sub.2 O-- repeating units and
• HAO1 represents a hydrophilic alkylene oxide block linking unit containing --CH.sub.2 CH.sub.2 O-- repeating units forming 4 to 35 percent of the total surfactant molecular weight.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on the total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing at least 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 800 to 30,000 satisfying the formula:
• HAO2--LAO2--HAO2
• where
• HAO2 each occurrence represents a terminal hydrophilic alkylene oxide block unit and
• LAO2 represents a lipophilic alkylene oxide block linking unit, contains at least thirteen --CH(CH.sub.3)CH.sub.2 O-- repeating units, and accounts for from 15 to 95 percent of the total surfactant molecular weight.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on the total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing less than 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 800 to 30,000 satisfying the formula:
• HAO2--LAO2--HAO2
• where
• HAO2in each occurrence represents a terminal hydrophilic alkylene oxide block linking unit containing --CH.sub.2 CH.sub.2 O-- repeating units and
• LAO2 represents a lipophilic alkylene oxide block linking unit containing at least thirteen --CH(CH.sub.3)CH.sub.2 O-- repeating units and accounting for from 40 to 96 percent of the total surfactant molecular weight.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on the total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing at least 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 1,100 to 60,000 satisfying the formula:
• (H--HAO3--LAO3).sub.2 --L--(LAO3--HAO3--H).sub.2
• where
• L represents an ethylene diamine linking unit,
• LAO3 in each occurrence represents a lipophilic alkylene oxide block unit containing at least three --CH(CH.sub.3)CH.sub.2 O-- repeating units,
• HAO3 in each occurrence represents a hydrophilic alkylene oxide block unit containing at least two --CH.sub.2 CH.sub.2 O-- repeating units and
• L and LAO3 in all occurrences together account for 15 to 95 percent of the total surfactant molecular weight.

A radiographic element comprised of

• a film support capable of transmitting radiation to which said radiographic element is responsive having opposed major surfaces, and, coated on said opposed major surfaces,
• emulsion layer units comprised of a vehicle and spectrally sensitized silver halide tabular grains having an average tabularity of greater than 25, where the tabularity of each tabular grain is the ratio of its equivalent circular diameter in micrometers divided by the square of its thickness in micrometers, and,
• interposed between each of said emulsion layer units and said support, means for reducing crossover of radiation to which said emulsion layer units are responsive to less than 10 percent,
• CHARACTERIZED IN THAT
• each of said emulsion layer units exhibit a coefficient of variation of less than 10 percent, based on the total grain population having an equivalent circular diameter of greater than 0.1 .mu.m, greater than 97 percent of the projected area of the grain population having an equivalent circular diameter of greater than 0.1 .mu.m being accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m and a halide content of bromide and from 0 to 5 mole percent iodide, based on total silver and
• the vehicle is comprised of a gelatino-peptizer containing at least 30 micromoles per gram of methionine and a polyalkylene oxide block copolymer surfactant having a molecular weight in the range of from 1,100 to 50,000 satisfying the formula:
• (H--LAO4--HAO4).sub.2 --L'--(HAO4--LAO4--H).sub.2
• where
• L' represents an ethylene diamine linking unit,
• LAO4 in each occurrence represents a lipophilic alkylene oxide block unit containing at least three --CH(CH.sub.3)CH.sub.2 O-- repeating units,
• HAO4 in each occurrence represents a hydrophilic alkylene oxide block unit containing --CH.sub.2 CH.sub.2 O-- repeating units, and
• L' and LAO4 in all occurrences together account for 5 to 85 percent of the total surfactant molecular weight.