GB984968A - Photographic printing - Google Patents

Photographic printing

Info

Publication number
GB984968A
GB984968A GB17307/62A GB1730762A GB984968A GB 984968 A GB984968 A GB 984968A GB 17307/62 A GB17307/62 A GB 17307/62A GB 1730762 A GB1730762 A GB 1730762A GB 984968 A GB984968 A GB 984968A
Authority
GB
United Kingdom
Prior art keywords
lamp
tungsten
motor
supply
photographic
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
GB17307/62A
Inventor
Denis Manktelow Neale
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.)
Ilford Imaging UK Ltd
Original Assignee
Ilford Ltd
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 Ilford Ltd filed Critical Ilford Ltd
Priority to GB17307/62A priority Critical patent/GB984968A/en
Priority to US275958A priority patent/US3213377A/en
Publication of GB984968A publication Critical patent/GB984968A/en
Expired legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
    • H05B41/14—Circuit arrangements
    • H05B41/36—Controlling
    • H05B41/38—Controlling the intensity of light
    • H05B41/39—Controlling the intensity of light continuously
    • H05B41/392—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor
    • H05B41/3921—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations
    • H05B41/3924—Controlling the intensity of light continuously using semiconductor devices, e.g. thyristor with possibility of light intensity variations by phase control, e.g. using a triac
    • 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

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Circuit Arrangements For Discharge Lamps (AREA)
  • Light Sources And Details Of Projection-Printing Devices (AREA)

Abstract

984,968. Supply systems for space discharge apparatus; control of A.C. motors. ILFORD Ltd. April 10, 1963 [May 4, 1962], No. 17307/62. Headings H2H and H2J. Photographic printing apparatus comprising both an electric discharge lamp and a tungsten filament lamp is provided with means for dimming the lamps so as to permit satisfactory printing of photographic negatives of differing density levels. The mean current flowing through the tungsten lamp is varied by means of a variable reactance X which may be of any suitable type such as a saturable reactor or a pair of reversely connected half-wave triggered rectifiers such as thyratrons or silicon controlled rectifiers whilst the light from the discharge lamp is intercepted at twice the frequency of the alternating current supply by a sectored shutter driven by a motor M connected in a bridge circuit comprising the variable reactance X, the tungsten lamp and a tapped impedance connected across the supply. Thus variation of the value of the reactance X simultaneously varies the current through the tungsten lamp and the phase, relative to that of the alternating current supply, of the voltage applied to the motor M with the result that the light intensity falling on the photographic negative from the discharge and tungsten lamps is varied. In a further embodiment the motor M is supplied from a bridge circuit together with a transformer and harmonic filter elements.
GB17307/62A 1962-05-04 1962-05-04 Photographic printing Expired GB984968A (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
GB17307/62A GB984968A (en) 1962-05-04 1962-05-04 Photographic printing
US275958A US3213377A (en) 1962-05-04 1963-04-26 Light modulation system using phase controlled synchronous motors

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB17307/62A GB984968A (en) 1962-05-04 1962-05-04 Photographic printing

Publications (1)

Publication Number Publication Date
GB984968A true GB984968A (en) 1965-03-03

Family

ID=10092883

Family Applications (1)

Application Number Title Priority Date Filing Date
GB17307/62A Expired GB984968A (en) 1962-05-04 1962-05-04 Photographic printing

Country Status (2)

Country Link
US (1) US3213377A (en)
GB (1) GB984968A (en)

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3435213A (en) * 1965-07-19 1969-03-25 Bell Telephone Labor Inc Light modulator using light choppers
US3590259A (en) * 1970-04-20 1971-06-29 Kinemotive Corp Chopper stabilized photoelectric transducer
US5896009A (en) * 1997-07-22 1999-04-20 Rosenwald; Jeffrey A. Extending the life of incandescent lamps by power factor modulation
ES2691029T3 (en) 2006-11-28 2018-11-23 Hayward Industries, Inc. Programmable underwater lighting system
US20110267834A1 (en) 2010-04-28 2011-11-03 Hayward Industries, Inc. Underwater Light Having A Sealed Polymer Housing and Method of Manufacture Therefor
US9031702B2 (en) 2013-03-15 2015-05-12 Hayward Industries, Inc. Modular pool/spa control system
US10057964B2 (en) 2015-07-02 2018-08-21 Hayward Industries, Inc. Lighting system for an environment and a control module for use therein
CN106993359A (en) * 2016-01-21 2017-07-28 金宝橱有限公司 Can Synchronization Control concatenation light fixture
US11720085B2 (en) 2016-01-22 2023-08-08 Hayward Industries, Inc. Systems and methods for providing network connectivity and remote monitoring, optimization, and control of pool/spa equipment
US20170212536A1 (en) 2016-01-22 2017-07-27 Hayward Industries, Inc. Systems and Methods for Providing Network Connectivity and Remote Monitoring, Optimization, and Control of Pool/Spa Equipment
US11168876B2 (en) 2019-03-06 2021-11-09 Hayward Industries, Inc. Underwater light having programmable controller and replaceable light-emitting diode (LED) assembly
US12060989B2 (en) 2019-03-06 2024-08-13 Hayward Industries, Inc. Underwater light having a replaceable light-emitting diode (LED) module and cord assembly

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1933831A (en) * 1932-07-29 1933-11-07 Eastman Kodak Co Photographic printing apparatus
US1971191A (en) * 1932-11-16 1934-08-21 Gen Electric Light responsive circuit controller
US1989187A (en) * 1932-12-17 1935-01-29 Gerald Alan S Fitz Vapor-electric control system
US2010610A (en) * 1933-03-01 1935-08-06 Gen Electric Coding apparatus

Also Published As

Publication number Publication date
US3213377A (en) 1965-10-19

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