GB349907A - Improvements in photographic printing apparatus - Google Patents

Improvements in photographic printing apparatus

Info

Publication number
GB349907A
GB349907A GB267530A GB267530A GB349907A GB 349907 A GB349907 A GB 349907A GB 267530 A GB267530 A GB 267530A GB 267530 A GB267530 A GB 267530A GB 349907 A GB349907 A GB 349907A
Authority
GB
United Kingdom
Prior art keywords
cell
printing
circuit
photographic printing
electric
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
GB267530A
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.)
DAVID HENRY FOLLETT
HILGER Ltd ADAM
Original Assignee
DAVID HENRY FOLLETT
HILGER Ltd ADAM
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 DAVID HENRY FOLLETT, HILGER Ltd ADAM filed Critical DAVID HENRY FOLLETT
Priority to GB267530A priority Critical patent/GB349907A/en
Publication of GB349907A publication Critical patent/GB349907A/en
Expired legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/4209—Photoelectric exposure meters for determining the exposure time in recording or reproducing
    • G01J1/4223—Photoelectric exposure meters for determining the exposure time in recording or reproducing specially adapted for copy - or printing apparatus

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Manufacture Or Reproduction Of Printing Formes (AREA)

Abstract

349,907. Photographic printing meters. HILGER, Ltd., A., TWYMAN, F., and SMITH, C. F., 24, Rochester Place, Camden Road, and FOLLETT, D. H., 35, Dorset Road, Merton Park, both in London. Jan. 25, 1930, Nos. 2675 and 19618. [Classes 97 (i) and 98 (i).] In photographic printing apparatus in which means are provided for varying the time of exposure according to the intensity of the light falling on the printing surface, such as are described in Specification 344,900, means are provided to compensate for the failure of Bunsen's Reciprocity law. In one form the means comprise a photo-electric cell acting as a leak in the circuit of Specification 344,900. A modified form of this circuit is shown in the Figure in which a cell 1, illuminated by the printing light, is connected between the grid and cathode of a triode 6, a compensating cell 12 being connected between the grid and anode, this cell operating as a leak to the charge supplied to a condenser 8 through the cell 1. In another form a density wedge or a plate perforated with holes of varying diameter or spacing is moved between the printing light and the photo-electric cell. Alternatively, a heat responsive body e.g. a mercury thermometer of which the thread completes an electric circuit may be substituted for the apparatus of Specification 344,900.
GB267530A 1930-01-25 1930-01-25 Improvements in photographic printing apparatus Expired GB349907A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB267530A GB349907A (en) 1930-01-25 1930-01-25 Improvements in photographic printing apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB267530A GB349907A (en) 1930-01-25 1930-01-25 Improvements in photographic printing apparatus

Publications (1)

Publication Number Publication Date
GB349907A true GB349907A (en) 1931-05-26

Family

ID=9743781

Family Applications (1)

Application Number Title Priority Date Filing Date
GB267530A Expired GB349907A (en) 1930-01-25 1930-01-25 Improvements in photographic printing apparatus

Country Status (1)

Country Link
GB (1) GB349907A (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1156643B (en) * 1956-06-26 1963-10-31 Voigtlaender Ag Device for automatic exposure control
DE3325461A1 (en) * 1982-07-15 1984-01-19 Canon K.K., Tokyo IMAGE GENERATION DEVICE

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1156643B (en) * 1956-06-26 1963-10-31 Voigtlaender Ag Device for automatic exposure control
DE3325461A1 (en) * 1982-07-15 1984-01-19 Canon K.K., Tokyo IMAGE GENERATION DEVICE
GB2125976A (en) * 1982-07-15 1984-03-14 Canon Kk Line-by-line-photocopier

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