GB790509A - Controlling photographic exposure by photo-electric means - Google Patents

Controlling photographic exposure by photo-electric means

Info

Publication number
GB790509A
GB790509A GB24737/55A GB2473755A GB790509A GB 790509 A GB790509 A GB 790509A GB 24737/55 A GB24737/55 A GB 24737/55A GB 2473755 A GB2473755 A GB 2473755A GB 790509 A GB790509 A GB 790509A
Authority
GB
United Kingdom
Prior art keywords
light
photo
spot
sensitive surface
multiplier
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
GB24737/55A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RICHARD NEWHALL JOHNSON
Original Assignee
RICHARD NEWHALL JOHNSON
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by RICHARD NEWHALL JOHNSON filed Critical RICHARD NEWHALL JOHNSON
Publication of GB790509A publication Critical patent/GB790509A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/72—Controlling or varying light intensity, spectral composition, or exposure time in photographic printing apparatus
    • G03B27/725—Optical projection devices wherein the contrast is controlled electrically (e.g. cathode ray tube masking)

Landscapes

  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Projection-Type Copiers In General (AREA)

Abstract

790,509. Photo-electric printing control. JOHNSON, R. N. Aug. 29, 1955 [Sept. 2, 1954], No. 24737/55. Class 40 (3). A subject to be photographed is illuminated with a scanning spot of light from a cathoderay tube and reflects or transmits the light to a light-sensitive surface, and a light-sensitive cell senses the intensity of the light transmitted or reflected by the light-sensitive surface and so modifies the scanning speed, spot sign or spot intensity that the average exposure of each area of the light-sensitive surface remains substantially constant. As shown in Fig. 1, a scanning spot of light from a cathode-ray tube 10 passes through a negative 26 and a light-sensitive printing paper 30 to a photo-multiplier 34 in a light collector 36. The photo-multiplier is connected through an amplifier 38 to the control grid 14 of the cathode-ray tube so as to modify the spot intensity to provide uniform exposure of each part of the negative. In an alternative arrangement described with reference to Fig. 2 (not shown) a photo-multiplier tube receives light reflected from the photo-sensitive surface which is mounted on an opaque support while in the arrangement of Fig. 3 (also, not shown) the photo-electric cell is mounted behind the photosensitized surface which receives light from the object being photographed. Specification 435,749, [Group XL], is referred to.
GB24737/55A 1954-09-02 1955-08-29 Controlling photographic exposure by photo-electric means Expired GB790509A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US790509XA 1954-09-02 1954-09-02

Publications (1)

Publication Number Publication Date
GB790509A true GB790509A (en) 1958-02-12

Family

ID=22148102

Family Applications (1)

Application Number Title Priority Date Filing Date
GB24737/55A Expired GB790509A (en) 1954-09-02 1955-08-29 Controlling photographic exposure by photo-electric means

Country Status (1)

Country Link
GB (1) GB790509A (en)

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