(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 |
(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.