(19)
(11) EP 0 184 078 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
17.11.1988 Bulletin 1988/46

(43) Date of publication A2:
11.06.1986 Bulletin 1986/24

(21) Application number: 85114809

(22) Date of filing: 21.11.1985
(84) Designated Contracting States:
BE DE FR GB

(30) Priority: 06.12.1984 IT 2393884

(71) Applicant: MINNESOTA MINING AND MANUFACTURING COMPANY
 ()

(72) Inventors:
  • Sgarbi, Aldo
     ()
  • Vacca, Alberto
     ()
  • Beretta, Paolo
     ()
  • Kitchin, Jonathan Peter
     ()

   


(54) Method for etching half-tone silver halide images and silver halide photosensitive material for half-tone image reproduction


(57) A black and white silver halide photosensitive material for contact copying of dot (or line) images comprises a high-chloride fine-grain silver halide emulsion reactively associated with a compound selected from the group of thiazolium salt compounds, thiazole compounds and pyrazole compounds. Said compounds are preferably added to the silver halide emulsion in combination with a mercaptotetrazole compound. The photosensitive material allows, during the photomechanical etching process, a significant reduction in the area of the dots without causing a significant reduction of small dots.





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