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Expired Canadian patentCanada

Process control for photographic processing apparatus

CA 2102135 C · Owner: Saunders, Arthur E. · Inventors: Saunders, Arthur E.; Green, Andrew

CIPO record

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Abstract From the Canadian patent

A method of controlling photographic, processing apparatus when processing a given photographic material using the characteristic curve for that material, the characteristic curve being determined from a control strip of the photographic material, the control strip being produced exposing the control strip to a step wedge, and processing the exposed strip in the processing apparatus to be controlled, the characteristic curve being determined by measuring density values from the processed control strip in relation to the exposure applied to the strip in the step wedge, and plotting these density in relation to the exposure, characterized in that the characteristic curve is defined by:, D = …

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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

  • Filed November 1, 1993 and granted January 12, 1999. A Canadian patent filed from October 1, 1989 lasts 20 years from filing, so its term ended November 1, 2013.
  • A certificate of supplementary protection adds at most two years for a drug, so even that would have ended by November 1, 2015.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledNovember 1, 1993
GrantedJanuary 12, 1999
Term endedNovember 1, 2013
Patent numberCA 2102135 C
Classification (IPC)G03C5/02 +1 more

Timeline

Timeline From CIPO dates

1994199619982000200220042006200820102012Application filedNov 1, 1993Patent grantedJan 12, 1999Term endedNov 1, 2013

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