Patents by Inventor Keith A. Penfound

Keith A. Penfound has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4857450
    Abstract: High contrast negative acting silver halide emulsions suitable for laser scanning applications comprising a Group VIII metal compound and one or more spectrally sensitizing dyes of the formula ##STR1## The emulsions have good long term stability and good sensitivity.
    Type: Grant
    Filed: April 27, 1987
    Date of Patent: August 15, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Ronald W. Burrows, Keith A. Penfound, Bernard A. Lea
  • Patent number: 4828962
    Abstract: Photographic elements comprising a negative working silver halide emulsion containing high intensity reciprocity failure reducing amounts of dopant comprising both ruthenium and iridium ions.
    Type: Grant
    Filed: September 8, 1987
    Date of Patent: May 9, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Nicholas E. Grzeskowiak, Keith A. Penfound
  • Patent number: 4824770
    Abstract: A process for producing a continuous tone color image comprising providing a light sensitive photographic element comprising a substrate bearing three imaging media coated thereon, said imaging media comprising:(1) an imaging medium capable of forming a yellow image upon imagewise exposure and processing,(2) an imaging medium capable of forming a magenta image upon imagewise exposure and processing,(3) an imaging medium capable of forming a cyan image upon imagewise exposure and processing,each imaging medium having a maximum spectral sensitivity at a wavelength different from that of the maximum spectral sensitivity of the other imaging media within the range 550 to 900 nm, the sensitivities at the wavelength of maximum spectral sensitivity of the media decreasing in order from the medium of shortest wavelength maximum spectral sensitivity to the medium of longest wavelength maximum spectral sensitivity, the difference in said sensitivities between the media of shortest and longest wavelength maximum spectra
    Type: Grant
    Filed: April 9, 1987
    Date of Patent: April 25, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Jonathan P. Kitchin, Stephen R. Powers, Keith A. Penfound, Peter J. Finn
  • Patent number: 4814827
    Abstract: A radiation-sensitive element for half tone color proofing adapted to be exposed by scanning with four independently modulated sources of radiation emitting at different wavelengths within the range 550 to 900 nm, the element comprising a substrate bearing at least four separate imaging media coated thereon, said imaging media including:(1) an imaging medium capable of forming a yellow image upon imagewise exposure and processing,(2) an imaging medium capable of forming a magenta image upon imagewise exposure and processing,(3) an imaging medium capable of forming a cyan image upon imagewise exposure and processing, and(4) an imaging medium capable of forming a black or a balancing black image upon imagewise exposure and processing,each imaging medium having a maximum spectral sensitivity at a wavelength different from that of the maximum sensitivity of the other imaging media such that after exposure and processing super-imposed yellow, magenta, cyan and black or balancing black images are formed, each image
    Type: Grant
    Filed: August 13, 1987
    Date of Patent: March 21, 1989
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Jonathan P. Kitchin, Stephen R. Powers, Keith A. Penfound, Peter J. Finn, Michael G. Fisher
  • Patent number: 4705745
    Abstract: A radiation-sensitive element for half tone color proofing adapted to be exposed by scanning with four independently modulated sources of radiation emitting at different wavelengths within the range 550 to 900 nm, the element comprising a substrate bearing at least four separate imaging media coated thereon, said imaging media including:(1) an imaging medium capable of forming a yellow image upon imagewise exposure and processing,(2) an imaging medium capable of forming a magenta image upon imagewise exposure and processing,(3) an imaging medium capable of forming a cyan image upon imagewise exposure and processing, and(4) an imaging medium capable of forming a black or a balancing black image upon imagewise exposure and processing,each imaging medium having a maximum spectral sensitivity at a wavelength different from that of the maximum sensitivity of the other imaging media such that after exposure and processing super-imposed yellow, magenta, cyan and black or balancing black images are formed, each image
    Type: Grant
    Filed: March 3, 1986
    Date of Patent: November 10, 1987
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: Jonathan P. Kitchin, Stephen R. Powers, Keith A. Penfound, Peter J. Finn, Michael G. Fisher
  • Patent number: 4476220
    Abstract: Photothermographic emulsions display enhanced spectral sensitization when the silver halide grains are formed in the presence of one or more spectral sensitizing dyes.
    Type: Grant
    Filed: July 1, 1983
    Date of Patent: October 9, 1984
    Assignee: Minnesota Mining and Manufacturing Company
    Inventor: Keith A. Penfound