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Expired Canadian patentCanada

Divalent chalcogenide fog inhibiting agents for silver halide photography

CA 1268983 C · Owner: Gunther, Wolfgang Hans Heinrich · Inventors: Lok, Roger; Gunther, Wolfgang Hans Heinrich

CIPO record

Overview

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Its claims, description and drawings are in the Canadian Patents Database.

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Abstract From the Canadian patent

Abstract of the Disclosure Radiation sensitive silver halide photographic elements are disclosed which are protected from fog by aromatic tellurochalcogenides. The aromatic tellurochalcogenides can be initially incorporated in the photographic element as manufactured or during processing.

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted May 15, 1990. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended May 15, 2007.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledFebruary 12, 1986
GrantedMay 15, 1990
Term endedMay 15, 2007
Patent numberCA 1268983 C
Classification (IPC)G03C1/34

Timeline

Timeline From CIPO dates

1987199019931996199920022005Application filedFeb 12, 1986Patent grantedMay 15, 1990Term endedMay 15, 2007

Sources & verification

Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.