US3752577A - Light-correction system for printers of colour cinematographic films - Google Patents

Light-correction system for printers of colour cinematographic films Download PDF

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Publication number
US3752577A
US3752577A US00198590A US3752577DA US3752577A US 3752577 A US3752577 A US 3752577A US 00198590 A US00198590 A US 00198590A US 3752577D A US3752577D A US 3752577DA US 3752577 A US3752577 A US 3752577A
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United States
Prior art keywords
light
cam
blade
flux
operating shaft
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Expired - Lifetime
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US00198590A
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English (en)
Inventor
R Grossetete
J Blaublomme
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ANDRE DEBRIE FR Ets
DEBRIE ANDRE ETS
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DEBRIE ANDRE ETS
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    • 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
    • G03B27/73—Controlling exposure by variation of spectral composition, e.g. multicolor printers
    • G03B27/735—Controlling exposure by variation of spectral composition, e.g. multicolor printers in dependence upon automatic analysis of the original
    • 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

Definitions

  • ABSTRACT 22 Filed: Nov. 15 1971 A light-correction system for cinemato raphic colour 1 1 3 8 film printers which operate on the additive three- [21] Appl' 198590 colour principle.
  • Electric pulses originating in binary form from a reader of a perforated programming tape [30]
  • Foreign Application Pri rit D t on which information relating to desired corrections is Dec. 16 1970 France 7045353 med, are each the Plimary ours by a digital-analogue arrangement into a represen- 52 u.s. c1 355/36 355/34 355/83 alive elem and Penin8 each 511 Im. c1. 00313 27/76 mslmdin!
  • Each of the flux modulators includes [56] References Cited a cam for converting rotation of the corresponding motor into angular displacement of a pivoting member UNITED STATES PATENTS mounted for rotation on an operating shaft of an aper- 3,552,852 1/1971 Sternke et a1.
  • the present invention relates to optical or contact printing machines for use with colour cinematographic films, and is concerned more particularly with a lightcorrection system which makes it possible to obtain copies exhibiting desired effects on projection from a given original. This system is applicable more particularly to printing machines operating by the additive three-colour principle.
  • the aforesaid process involves splitting up the light flux emitted by a light source, such as an incandescent or halogen lamp, into three monochromatic parallel beams each corresponding to one of the primary colours (red, green, blue).
  • the light flux is split up by means of a system of filtering foils or'reflecting mirrors.
  • Each of these three beams passes through a flux modulator which is adapted to cause the intensity of the beam to vary as a function of a prestablished instruction programme.
  • the three beams are then recombined into a single light beam by a system of foils and reversing mirrors, the spectral composition'of which can thus be modified at will with respect to that of the initial beam.
  • This recombined beam serves to illuminate the images of the original film in succession to provide for the production of an optical or contact copy.
  • the desired intensity variations are determined from a previous projection of the original with a suitable grading device which establishes the different intensity variations for the various sequences of the film in question.
  • the information obtained by the grading device is stored in coded form on a programming tape having six perforated tracks in accordance with the binary numbering system. These six perforated tracks thus make it possible to establish a total of 50 bits of information each corresponding to one adjustment step in the aperture of the respective flux modulator for each of the three primary colours.
  • the aperture variation causes a suitable variation in the intensity of light leaving each modulator.
  • the printing of the copies is effected using the information carried by the programming tape.
  • the tape advances step-by-step with each change in film sequence in a suitable reader.
  • the reader is provided without contacts which are closed or open depending on whether there is a perforation on the corresponding track and for the colour under consideration or not.
  • the use of the information thus translated into electric pulses is dependent on electromagnetic relay systems which operate as many cams as there are tracks on the programming tape, (six in the present instance). These cams are of progressively increasing height and their deviation is totalised to act mechanically on an iris or blade-type arrangement, which modulates the light beam of the primary colour in question.
  • a process for adjusting a light-correction system of a cinematographic colour film printing machine which operates on the additive three-colour principle in which the light flux emitted by a source is split up into three monochromatic beams which are each passed through the flux modulator and thereafter recombined, the process comprising the steps of, recording correction information on a perforated programming tape.
  • the present invention also provides a lightcorrection system for a cinematographic colour film printing machine which is adapted to operate on the additive three-colour principle in which the light flux emitted by a source is split up into three monochromatic beams which are each passed through a flux modulator and thereafter recombined, the system comprising, means for advancing a perforated programming tape on which correction information is recorded step-by-step with the advance of a film to be printed, a programming tape reading adapted to produce an output of electric pulses a digital-analogue arrangement adapted to convert the pulses relating to each of the said monochromatic beams into a representative electrical voltage, and means for separately adjusting the aperture of each of the flux modulators, and electric motor connected to each of the said adjusting means, and a position-controlling potentiometric assembly adapted to supply the motor with the said voltage.
  • the adjustment of the aperture of the flux modulator is deferred with respect to the information stored on the programming tape and is triggered by a reference notch or index carried by the film so as to be produced in the interval of a change in sequence.
  • the rotation of the controlling electric motor is converted into an angular displacement of a pivoting member mounted for rotation on the operating shaft of the closure shutter or shutters of the flux modulator, and this operating shaft is only made fast angularly with the one said pivoting member during a short time period which is within the interval of the change in sequence.
  • the angular interlocking of the said pivoting member with the operating shaft of the closure shutter or shutters is controlled, against the action of a return spring, by an electromagnet receiving an electric pulse indicative of a change in sequence.
  • FIG. 1 is a simplified electric circuit diagram of a light-correction system according to the invention, only one of the three light flux modulators being shown;
  • FIG. 2 and 3 are longitudinal and transverse sections, respectively of a flux modulator.
  • the system for electrically controlling the flux modulators comprises firstly a regulated electric supply system (not shown), and a means for controlling the advance of the programming tape and the deferred use of the information stored by it, said means comprising an order-initiating memory M operated by a reference index or notch carried by the original film at the location of each change in sequence, a delay arrangement R designed to take into accountthe distance between the index-sensing device of the preceding memory and the projection-aperture, a monostable triggering device B controlled by the signal as thus deferred, a pulse emitter E initiated by the' said triggering device, and a step selector 5,, switching the pulses received from the preceding emitter in succession towards each of the three circuits associated with the flux modulators.
  • a regulated electric supply system not shown
  • a means for controlling the advance of the programming tape and the deferred use of the information stored by it said means comprising an order-initiating memory M operated by a reference index or notch carried by the original film at the location
  • the control system additionally comprises three individual control circuits, each associated with one of the flux modulators corresponding to the three primary colours.
  • Each of these circuits comprises a memory M M or M; of convention design, the inputs of which are directly connected to the track-contacts of the programming tape reader L, as well as a digital-analogue converter C C or C which is adapted to translate the information received in the form of a binary signal from the associated memory into a proportional continuous electric voltage.
  • the three memories M M and M are controlled by the step or spacing selector S, which sequentially controls their opening, and also by a clearing circuit (not shown). The essential purpose of these memories is to record the information received from the programming tape reader L with each advance of this latter and to keep the information availv able at the input of the associated converters as long as is necessary for use of the recured information.
  • a flux modulator is illustrated diagrammatically in FIG. 1.
  • the light flux modulator comprises a rigid housing 1 into the upper portion of which two aligned circular windows 2 and 2 are drilled.
  • Two symmetrical opaque shutter members 3 and 3' are disposed between the windows keyed on two parallel and spaced rotating shafts. The displacements of the two shutters are synchronised and take place in opposite directions, so that they offer an aperture of variable surface area to the passage of light beams (shown shaded in FIG. 3). Consequently, they intercept a larger or smaller fraction of thc'light flux admitted through the windows 2 and 2'.
  • the closure shutter 3 is more specifically fixed to the end of a hollow shaft 4 journalling by means of ballbearings in a reinforced wall of the housing 1.
  • the hollow shaft 4 also carries at the same end a member 5 machined in the form of a cam having re-entrant surfaces, and also a toothed wheel 6 adapted to mesh with as little play as possible with an identical toothed wheel 6 keyed on the shaft of the other shutter 3', the shaft wheels thus making the rotational movements of these two shutters synchronised as already mentioned above.
  • the hollow shaft 4 carries a circular plate 7 forming a brake element.
  • a sliding rod 8 Arranged coaxially with the hollow shaft 4 is a sliding rod 8 which is rigidly attached to a plunger 9 of an electromagnet 10.
  • the plunger In the absence of energisation of the control winding, the plunger is biased by the action of a spring out of the coil, in which position it comes into contact with the circular plate 7 and thus by friction immobilises the hollow shaft 4 in the angular position which it, has reached whenthe plunger contacts the plate 7.
  • the rod 8 carries a stop or abutment collar 11 at its free end.
  • the end of a pivoting blade 13 is held against the stop 11 by the action of a compression spring 12.
  • the pivoting blade 13 is connected at its other end by a fork joint to the cranked end of a lever 14 which is mounted for pivotal movement by means of a roller bearing on the hollow shaft4.
  • the blade 13 is provided at its upper end with a pair of aligned lateral projections which support rollers 15 and 15' which are adapted to engage the re-entrant surfaces of the cam 5, but which are normally held spac'ed from-these surfaces by the action a blade return spring 12.
  • the displacements of the pivoting lever 14 are controlled by a direct current electric motor 16 via a speed reduction gear by meansof a rotatable cam 18 keyed on the motor shaft 17 and a roller 19 mounted on the pivoting lever and held in contact with the cam by a tension spring 20.
  • a slide member of a position control potentiometer 21 is keyed on the shaft 17.
  • the electrical control means of the flux modulator comprises essentially two circuits.
  • the first which controls the operationof the electromagnet 10, transmits to the latter, through an amplifier A a suitable deferred electric control pulse having a sufficiently short duration (for example, m8), so that the execution of the desired correction takesgplace in the interval separating the first image of thetsequence in question of the film from the last image of the preceding sequence.
  • the second circuit which is associated with the motor 16, comprises a potentiometric assembly 22 which is acted upon by the digital-analogue converter C through an amplifier A,, an amplifier A of similar form but having a gain equal to the unit being introduced for the purpose of correction of thermal deviation in the opposite branch of the assembly .connected to the position-control potentiometer 21.
  • a third amplifier A having a reaction loop, in its turn acts on the motor 16 from the potentiometric assembly 22, this amplifier being in addition influenced by the position of an auxiliary potentiometer 23, called the correction threshold, which is regulated as a function of the characteristics of the film emulsion being used.
  • the coded information relating to the sequence following that which is undergoing printing travel in succession, for each of the primary colours, beneath the contacts of the tape reader L; by the co-ordinating action of the step selector S the three memories M,, M and M are successively opened to the pulses originating from the tape reader, each of these memories only retaining the instructions relating to the fundamental colour with which it is associated.
  • the advance of the programming tape is ended by a fourth step corresponding to a stopping position.
  • Each of the three memories M M and M thus records the correction information relating to the colour in question and transmits it to the associated digital-analogue converter C C C throughout the time necessary for the preparation of the execution by the motor 16 and by the associated position control of the corresponding flux modulator.
  • FIG. 1 of the accompanying drawings the control system shown diagrammatically in FIG. 1 of the accompanying drawings is able, despite its relative complexity, to be kept within the limits of acceptable size, this being particularly due to the use of miniaturised elements and integrated circuits.
  • the flux modulators in FIGS. 2 and 3 can in their turn be easily made in the form of units of small dimensions and reduced weight, these advantages moreover being concurrent with a desirable reduction in the inertia of the movable components, and consequently of the response times
  • the present invention thus permits the development of a light correction system which is lighter, more compact and responds more rapidly'than the mechanical control systems as known at the present time.
  • a light-correction system for a cinematographic color film printingmachine which is adapted to operate on the additive three-color principle in which the light flux emitted by a source is split up into three monochromatic beams which are each passed through a flux modulator and thereafter recombined, the system comprising, means for advancing a perforated programming tape on which correcting information is recorded step-by-step with the advance of a film to be printed,
  • a programming tape reader for producing an output of electric pulses, a digital-analogue arrangement for converting the electric pulses into representative electrical voltages; means for separately adjusting the aperture of each of the fluxmodulators, said adjusting means including an aperture shutter and corresponding operating shaft for each flux modulator a separate electric motor for driving each of said adjusting means; separate position-controlling potentiometric assemblies for coupling each of the motors with one of the representative voltages; means for storing correction information supplied by the reader; means for sensing an index mark carried by the film; means for extracting the stored information when an index mark is sensed; a cam mounted in each of the flux modulators, for converting rotation of each corresponding motor into an angular displacement of a pivoting member mounted for rotation on an operating shaft of an aperture shutter of the respective flux modulator; means for making the operating shaft fast with the said pivoting member during a short time interval initiated by the index mark sensing means; the pivoting member comprising a lever journalled at one of the ends on the operating shaft of the corresponding aperture shutter and
  • a light-correction system wherein the operating shaft of the aperture shutter is hollow and in that the pivot means for the engagement of the blade with the cam is controlled by means of a sliding rod disposed coaxially of the said shaft and operated by the plunger of the electromagnet.
  • a light-correction system according to claim 2, wherein a friction connection is established by the action of said spring on the blade between the sliding rod and the hollow shaft so as to immobilise the latter in the last angular position which was communicated to it by

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  • Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Physics & Mathematics (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Projection-Type Copiers In General (AREA)
  • Mechanical Light Control Or Optical Switches (AREA)
US00198590A 1970-12-16 1971-11-15 Light-correction system for printers of colour cinematographic films Expired - Lifetime US3752577A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7045353A FR2118283A5 (enrdf_load_stackoverflow) 1970-12-16 1970-12-16

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US3752577A true US3752577A (en) 1973-08-14

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US00198590A Expired - Lifetime US3752577A (en) 1970-12-16 1971-11-15 Light-correction system for printers of colour cinematographic films

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US (1) US3752577A (enrdf_load_stackoverflow)
BE (1) BE776007A (enrdf_load_stackoverflow)
DE (1) DE2162529C3 (enrdf_load_stackoverflow)
FR (1) FR2118283A5 (enrdf_load_stackoverflow)
GB (1) GB1384554A (enrdf_load_stackoverflow)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3923393A (en) * 1972-11-24 1975-12-02 Canon Kk Electrophotographic color copying apparatus of the color resolving type
US4003652A (en) * 1975-02-25 1977-01-18 F & B/Ceco Industries, Inc. Shutter-opening presetting mechanism for motion picture copying apparatus
US4008962A (en) * 1973-10-15 1977-02-22 Minnesota Mining And Manufacturing Company Color printing method
US4108537A (en) * 1976-12-30 1978-08-22 Bell & Howell Company Light valve system for motion picture film printer
US6795158B1 (en) 2002-04-03 2004-09-21 Technicolor, Inc. Real time answerprint timing system and method

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2488150B1 (fr) * 1980-08-08 1986-04-04 Bertin & Cie Dispositif d'ejection de gouttelettes a la demande

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3517996A (en) * 1967-12-26 1970-06-30 Joseph R Jones Microfilming system
US3519347A (en) * 1968-01-26 1970-07-07 Itek Corp Automatic printer systems
US3552852A (en) * 1968-08-19 1971-01-05 Peterson Enterprises Inc Film copying apparatus
US3576370A (en) * 1967-10-27 1971-04-27 Agfa Gevaert Ag Exposure time control system for photographic apparatus
US3602579A (en) * 1969-11-17 1971-08-31 Film Editing Equipment Corp Electromechanical light valve system
US3642377A (en) * 1969-12-02 1972-02-15 Xerox Corp Color printing system

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3576370A (en) * 1967-10-27 1971-04-27 Agfa Gevaert Ag Exposure time control system for photographic apparatus
US3517996A (en) * 1967-12-26 1970-06-30 Joseph R Jones Microfilming system
US3519347A (en) * 1968-01-26 1970-07-07 Itek Corp Automatic printer systems
US3552852A (en) * 1968-08-19 1971-01-05 Peterson Enterprises Inc Film copying apparatus
US3602579A (en) * 1969-11-17 1971-08-31 Film Editing Equipment Corp Electromechanical light valve system
US3642377A (en) * 1969-12-02 1972-02-15 Xerox Corp Color printing system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3923393A (en) * 1972-11-24 1975-12-02 Canon Kk Electrophotographic color copying apparatus of the color resolving type
US4008962A (en) * 1973-10-15 1977-02-22 Minnesota Mining And Manufacturing Company Color printing method
US4003652A (en) * 1975-02-25 1977-01-18 F & B/Ceco Industries, Inc. Shutter-opening presetting mechanism for motion picture copying apparatus
US4108537A (en) * 1976-12-30 1978-08-22 Bell & Howell Company Light valve system for motion picture film printer
US6795158B1 (en) 2002-04-03 2004-09-21 Technicolor, Inc. Real time answerprint timing system and method

Also Published As

Publication number Publication date
DE2162529B2 (de) 1973-03-08
DE2162529A1 (de) 1972-06-29
DE2162529C3 (de) 1973-09-20
BE776007A (fr) 1972-03-16
GB1384554A (en) 1975-02-19
FR2118283A5 (enrdf_load_stackoverflow) 1972-07-28

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