US2842610A - Colour printing - Google Patents

Colour printing Download PDF

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Publication number
US2842610A
US2842610A US451466A US45146654A US2842610A US 2842610 A US2842610 A US 2842610A US 451466 A US451466 A US 451466A US 45146654 A US45146654 A US 45146654A US 2842610 A US2842610 A US 2842610A
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Prior art keywords
colour
spot
transparency
photo
intensity
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Expired - Lifetime
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US451466A
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English (en)
Inventor
Crosfield John Fothergill
Allen Gordon Stanley James
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CROSFIELD J F Ltd
J F CROSFIELD Ltd
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CROSFIELD J F Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/401—Compensating positionally unequal response of the pick-up or reproducing head
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/04—Scanning arrangements, i.e. arrangements for the displacement of active reading or reproducing elements relative to the original or reproducing medium, or vice versa
    • H04N1/207—Simultaneous scanning of the original picture and the reproduced picture with a common scanning device
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/46—Colour picture communication systems
    • H04N1/56—Processing of colour picture signals
    • H04N1/60—Colour correction or control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/46—Colour picture communication systems
    • H04N1/56—Processing of colour picture signals
    • H04N1/60—Colour correction or control
    • H04N1/6016—Conversion to subtractive colour signals

Definitions

  • This invention relates to the production of separation negatives or positives for use in colour reproduction, and more particularly to colour correction in such separation prints.
  • colour printing For colour printing, an original is generally photographed through a number of colour filters to produce colour separation negatives, and these are used to prepare printing cylinders or plates for the different colours to make multi-colour prints.
  • the separation negatives, or the positives made from them are not usually suitable for the preparation of printing surfaces directly, owing to the difficulties of obtaining colour filters and inks of suitable complementary colour response.
  • a printing ink which is nominal- -1y magenta may also reflect some light in the cyan part of the spectrum, so that, where both inks are printed at a given element of the picture, the weight of cyan ink applied should be reduced by an amount dependent on the amount of magenta ink applied.
  • each element of the colour separation positive or negative of each colour in accordance with the values of each of the other colours present in that element.
  • the uncorrected negative of each colour may be exposed through a pair of superimposed masks formed by partial exposure of negatives of the other two colours, to produce a corrected separation positive of that colour.
  • the degrees of partial exposure required to provide the correct degree of masking are difficult to control and results tend to be largely a matter of trial and error, and take a long tune.
  • each of the required colour separation prints is formed by direct exposure to a scanning spot of light, without the interposition of a mask or transparency in the light path from the source to the print to be exposed, and the intensity of the light spot is con trolled, element by element during scanning, by the output of an electrical 'computor which receives information from photo-electric cells receiving light of a number of colours passing through a transparency or through uncorrected separation prints, and originating in the same scanning spot.
  • the computer performs the necessary correction of the spot intensity to modify the exposure of each element ofthe print with respect to the values of the other colours present in the transparency or in the corresponding element of each of the uncorrected separation prints.
  • the corrected separation negative may be partially exposed by a scanning spot of light of constant intensity passed through the original and through a colour filter, being scanned a second time in the manner according to the invention, either subsequently or beforehand, in order to obtain the correction.
  • the scanning spot of light from the light source is, in general, in the method according to the invention, split ⁇ into two paths, by means for instance of a semisilvered mirror.
  • One path leads to the print to be prepared, while the other is used to derive the colour signals ⁇
  • this method makes it possible to expose the print fully for'those colour plates where the transparency is black. That is to say, it facilitates the v elimination of colour from the colour plates where' the of light of the colours to be used, each beam beingA outputs of photo-electric cells receiving light from the g focussed on the cathode of a photo-electric cell.
  • the electrical outputs of the photo-electric cells are amplified and fed into the computer to provide the information for controlling the intensity of the source.
  • the second path is split by means, for example, of partsilvered mirrors, into a number of beams equal to the number of uncorrected negatives, each beam being passed through an uncorrected negative onto the cathode of a ⁇ photo-electric cell, which is used to feed the computer as before.
  • the uncorrected negatives must, of course, be in register, so that the scanning spot passes through corresponding elements in each negative simultaneously.
  • the output of the computer controlling the intensity of the scanning spot may be used also to control means to render the input information tothe computer substantially independent of the instantaneous brightness of the scanning spot, so that it is dependent only on the relative densities of the diiferentcolours in the transparency or uncorrected prints.
  • the output of the computer may control in a reciprocal manner the gains of amplifiers feeding the different signals from the photo-electric cells into the computer.
  • the signals from the photo-electric cells may be divided by this output -of the computer in a logarithmic dividing circuit before being passed on to the computer.
  • a further photo-electric cell could be used to derive a signal proportional to spot intensity and feed the amplifiers or 3 dividing circuit in opposition to the signals, from ⁇ the main photo-electric cells in rthe sarne way.
  • the scanning spot of light may be obtained in various Ways, for example,k from a mechanical system involving a rotating mirror drum.
  • a small lamp of ⁇ high luminous intensity is placedA at the focus of alens which ⁇ forms a beam of parallel rays.
  • This beam falls on afrotating mirror drum and is reflected through a second lens, to bring it to a focus. to form a spot image.
  • the spot is caused to scan repeatedly along a straight line. If the lamp is now moved slowly in a direction parallel with the axis of the drum, spot image is caused to produce a complete raster scanning a rectangular area.
  • Figure 1 is a general schematic diagram ofthe optical system and electrical connections of* that form of the apparatus for use with transparencies
  • Figure 2 shows the modified optical systemfor use with uncorrected separation negatives or positives.
  • a cathode ray tube 1 has a at face 2, on which is produced a rectangular raster 3.
  • the usual focussing coil 4 is driven from a suitable circuit 5, and the deflection of the electron beam to produce the raster is obtained by electromagnetic deflection coils 6, driven from horizontal and vertical time base circuits indicated by the block 7.
  • the phosphor on the face 2 of the tube is of such a kind as to give effectivelyl white light covering as equally as possible all the wavelengths of the Visible spectrum.
  • the brightness of ⁇ the'raster may becontrolled in a well known manner byalteration ofthe potential of the grid 8. with respectto the cathode 9. It is, in fact continually varied by the application to the grid of a high frequency.
  • An image ofthe spot on the screen of the cathode-ray tube 1 is produced by a lens 11on the colour transparency shown at 12, and theraster is of such an amplitude that it just scans the wholeV of the transparency.
  • a partially silvered mirrorV 13 which diverts someof the light-throughalens 14 onto a plate 15 on which is the correctedA negative or positive to beformed.
  • Light from the spot transmitted by the transparency 12A is collected by a lens 16 and divided into three paths by partially silvered mirrors 17 and 18, so asto fall -on each of three photo-electric multiplier cells 19, 20. and 21.
  • a lter 22 say red, blue and green in front of cells 19, 20, 21, respectively. If dichroic mirrors were used instead of partially silvered ones at 17 and 18, the filters could, of course, be dispensed with.
  • the electrical outputs of the cells 19,120 and 21 are fed to cathode follower valve amplifiers 24, whose characteristic is that they have a high inputimpcdance and low -output impedance.
  • the output of each cathode follower circuit is proportional to the transmissionfactor of the transparency for the particular colour selectedby the lter in front of the corresponding cell, multiplied by the instantaneous brightness of the scanning spot.
  • the output signal from the cathode follower connected to cell 19 is proportional to the transmission factor of the transparency for red rays, and is torbe used vforpro- ⁇ ducing the printer of the complementary colour, namely,
  • cyan This will therefore be known as the cyan signal channel.
  • the channel from cell 20 is the yellow printer channel, and from cell 21 the magenta printer channel.
  • a photo-electric multiplier cell 25 feeding a cathode follower circuit 26.
  • t-he output of this circuit is proportional simply to the instantaneous brightness of the scanning spot. Its function is to provide a signal which, when divided into the signal from each of the other three cathode follower circuits, leaves a signal of magnitude dependent solely on the properties of the element of the transparency being scanned, and independent of spot brightness.
  • each of these circuits may comprise a high resistance in series with a germanium crystal rectifier. The inputvoltage is applied across the pair in series, so that the current through Iboth is substantially proportional to the input signal. Then the voltage developed across the rectifier will be substantially proportional to the logarithm of the input.
  • the logarithm of the ouput of cathode follower 29 is subtracted from that in each of the three colour channels in the mixing circuits 28M, ZSY and 2SC. This may be done very simply in a T resistance network, the output representing the difference being taken from the common resistance forming the centre stem of the T.
  • each mixing circuit is proportional to the sum of the logarithms yof the transmission factor for the particular colour and of t-he spot brightness. Output is therefore solely proportional to the-logarithm of the transmission factor. But the inverse density at any point in the transparency for a particular colour is itselfproportional to the logarithm of the transmission factor. So the output of each of the three mixing circuits 28M, 28Y and 28C Vis proportional to the inverse density of the transparency in respect of the colour of the corresponding filter 22, and hence proportional to the density of the complementary colour, i. e. the colour of the printer to be prepared from that channel.
  • Masking of each colour signal with respect to the other two is performed in the masking circuits 29M, 29Y and 29C.
  • Each of these circuits receives a signal from its ownV ⁇ channel and also from the other two channels throughtwo of the three inverting and attenuating circuits 30M, 30Y and 30C.
  • Each of the latter circuits inverts the signalrin itschannel to make it of opposite sign, and then attenuates it to two different levels, to be fed toV each'of the other two colourchannel masking circuits.
  • the circuit 30Y feeds a signal proportional to the yellow intensity to each of the masking circuits 29Mv and 29C in aV pre-determined proportion, tol reduce the signals in eachl of those channels by an amountV proportional to the, yellow signal.
  • the levels at which these masking signals are ⁇ fed into the other channels ⁇ are adjustable, and depend on the particular inks and colour lters used.
  • the corrected output signals in the three channels, magenta, yellow and cyan, are then passed to a circuit shown. in Figure 1 diagrammatically by the block 31.
  • Thefunction of this circuit 31, is to derive a fourth signal for the preparation of a,black printer.
  • this will, in a threecolour, process, call for the printing of a heavy weight of allthree colours, and in fact many ofthe elements of the original will call for the printing of all three colours to someextent.
  • Now heavy weights of all three colours may equally'. well ,bereplaced by the single-colour black, resulting in a considerable saving in the/expensive coloured inks', as well as giving improved4 reproduction. Accordingly, in the four-colour process, whenever possible, black should be used and the weights of the other three colours reduced, by the amount of the black printed, since black effectively replaces a combination of all three colours in a subtractive process.
  • the 'Ihe circuit 31 may achieve this in one of a number of Ways.
  • the three inputs from the colour channels could be fed to a conventional amplitude selection circuit, such as the anodes of three thermionic vdiode valve rectifiers, the cathodes of which are connected to a common load resistance. It is arranged that the signal of smallest amplitude of the three is the most positive. Then that signal will pass through its corresponding diode, raising the cathode potential and cutting off the other two.
  • the output signal for the fourth, or black printer is taken from the potential appearing across the load resistance, and each of the signals in the remaining channels is passed on reduced by this amount.
  • the smallest will be suppressed
  • the black will be passed on at this amplitude, and the other two reduced by part of the amount of the black signal.
  • Each of the signals is modified in two further ways before being applied to the grid 8 of the cathode ray tube 1, to control the spot intensity.
  • This modification is carried out in circuits 32 and 33 respectively in each of the four channels.
  • circuit 32 the density range of the print is altered to emphasise the highlights and shadows, by reducing the amplitude of the signal over its middle range of amplitudes. This is performed by passing the signal through a network of suitable non-linear ⁇ characteristics.
  • a similar non-linear circuit 33 in each channel modifies the signal to allow for the non-linear response of the cathode ray tube and of the phosphor in the different spectral regions, and arranges that the brightness of each spectral component of the spot is substantially linearly dependent of the output signal of the corresponding stage 32.
  • the grid 8 of the cathode ray tube 1 can be connected at will to any one of the four output signal channels, and in fact each is connected in turn while a complete scanning operation is performed to prepare a corrected separation print placed at 15. From these four corrected prints the printing cylinders may be prepared.
  • the cells and computer have an extremely rapid response which, for the sake of clearness, may be regarded as instantaneous, and, therefore, the analysis and correction are effectively carried out while the scanning spot is stationary.
  • the correcting action described therefore takes place in each element of the reproduction successively.
  • the negative to be prepared is scanned twice. It is scanned once through the transparency 12 and through a filter of the appropriate colour, the spot of light on the screen of the cathode ray tube being of constant intensity throughout the scanning operation.
  • the raster could be replaced in this case by a simple large light source of uniform brightness.
  • a second scanning operation is carried out by light from the spot or other light source without the interposition of a transparency or filter, While -simultaneously a second beam, divided from that scanning the negative to be prepared, scans the transparency yand falls on the cathodes of three photo-electric cells through colour filters as before, and the electrical outputs of these provide the information for colour correction, which is .fed into a computer to control the intensity Yof the light spot as before.
  • the negative is at first partially exposed in an uncorrected form and thelcorrection is applied subsequently in a second scanning operation.
  • signals from the photo-electric cells are divided by signals representing the spot intensity, in order to cancel the effect of variations of spot intensity in the input to the computer during this second scanning operation.
  • the signal for cancelling spot brightness variations instead of being taken from a photo-electric cell 25, could be taken directly from the signal fed to the grid 8 of the cathode ray tube. Again, instead of being divided logarithmically into the signals in the colour channels, it could be used to control reciprocally the gains of amplifiers through which the signals are fed, either by altering the screen grid potential of a valve, or by varying the grid bias of one or more variable mu stages, so that increase of spot brightness reduces the gain, and vice versa.
  • the invention has a number of substantial advantages.
  • the light source whilst the light source is permitted to vary in intensity in order to carry out the colour correction, this variation does not occur at the input to the computer from the colour analysing channels, due to the complementary variation in spot intensity and amplifier gain.
  • This feature makes it possible to use a single scanning source for both analysis and reproduction and to carry out colour correction to the very high order required by the colour printing industry.
  • Apparatus for producing corrected colour separation prints from a colour transparency comprising a light source of variable intensity, means for causing said source to scan over an area, a first image-forming means producing a first spot of light forming an image of said source on said transparency, means for dividing the iight beam of said irst spot passing through said transparency into a plurality of subsidiary beams, a light filter in the path of each of said subsidiary beams, a photo-electric cell in the path of each of said subsidiary beams, an electronic computer, said computer being electrically connected to said photo-electric cells, a second image-forming means producing a second spot of light forming an image of said variable intensity light source on a photosensitive surface, and means operated by said computer for controlling the brightness of said second spot.
  • Apparatus for producing corrected colour separation prints from a color transparency comprising a light source of variable intensity, means for causing said source to scan over an area of said transparency, a first image-forming means producing a rst spot of light forming an image of said source on said transparency, means for dividing the light beam of said rst spot passing through said transparency into a plurality of subsidiary beams, a light filter in the path of each of said subsidiary beams, a photo-electric cell in the path of each of said subsidiary beams, an electronic computer, said computer being electrically connected to said photoelectric cells, a second image-forming means producing a second spot of light forming an image of said variable intensity light source on Ia photo-sensitive surface, and means operated by said computer for controlling the intensity of said light source.
  • Apparatus according to claim 2 wherein said light source is a fluorescent spot on the screen of a cathoderay tube having a grid, and said means for controlling the intensity of said source includes the grid of said cathode-ray tube.
  • Apparatus for producing corrected colour separation prints from a plurality of uncorrected separation prints comprising a light source of variable intensity, a plurality of image-forming means, said image-forming means being arranged to form an image of said variable intensity light source on corresponding elements of each of said uncorrected prints, means for causing said source to scan over an area, a photo-electric cell in association with each of said uncorrected prints and adapted to receive light from said image of said source through said uncorrected print, an electronic computer, said computer being kelectrically connected to said photo-electric cells,
  • a further image-forming means forming a further image of said variable intensity light source on a photo-sensitive surface, and means operated by said computer for controlling the brightness of said further image.
  • Apparatus for producing corrected colour separation prints from a plurality of uncorrected separation prints comprising a light source of variable intensity, a plurality of image-forming means, said image-forming means being arranged tokform an image of said variable intensity light source on corresponding elements of each of said uncorrected prints, means for causing said source to scan over an area, a photo-electric cell in association with .eachof said uncorrected prints and adapted to receive light from said image of said source through said uncorrected print, an Aelectronic computer, said computer being electrically connected to said photo-electric cells,
  • ⁇ further image-forming means forming a further image of said variable intensity light source on a photo-sensitive surface, and means operated by said computer for controlling the intensity of said light source.
  • Apparatus according to claim 5 wherein said light source is a fluorescent spot on the screen of a cathoderay tube vhaving a grid, and said means for controlling the intensity of said source includes the grid of said cathode-ray tube.
  • Apparatus for producing corrected colour separation prints from a colour transparency comprising a cathoderay tube, said cathode-ray tube having a fluorescent screen and a grid controlling the intensity of the spot formed on said screen, a first image-forming means forming an image of said spot on said transparency, means for dividing the light beam from said image passing through said transparency into a plurality of subsidiary beams, a light lter in the ypath of each of said subsidiary beams, a photoelectric cell in the path of each of said subsidiary beams, an electronic computer, said computer receiving electrical signals from each of said photo-electric cells, and producing a signal controlling the electric potential of said grid, a second image-forming means forming an image of said spot on a photo-sensitive surface, and scanning means acting on said cathode-ray tube for causing said spot to traverse an area over said screen.
  • Apparatus according to claim 7, comprising also means responsive to the intensity of said spot and modifying the signals fed from said photo-electric cells to said computer in a manner such as to render said signals substantially independent of said intensity.
  • Apparatus according to claim 7, comprising also means responsive to the electric potential of said grid and modifying the signals fed from said photo-electric cells to said .computer in a manner such as to render said signals substantially independent of said intensity.
  • Apparatus for producing corrected colour separation prints from a plurality of uncorrected colour separation prints comprising a cathode-ray tube, said cathoderay tube having a fluorescent screen and a grid controlling the intensity of the luminous spot formed on said screen by the cathode ray, a plurality of image-forming means forming an image of said spot on corresponding elements of each of said uncorrected prints, a photo-electric cell associated with each uncorrected print and adapted to receive light from said image through said uncorrected print, an electronic computer fed with electric signals from each of said photo-electric cells and producing a signal controlling the electric potential of said grid, a further imageforming means forming an image of said spot on a photosensitive surface, and scanning means acting on said cathode-ray tube for causing said spot to traverse an area over said screen.
  • Apparatus according to claim 10 comprising also means responsive'to the intensity or" said spot and modifying the signals fed from said photo-electric cells to said computer in a manner such as to render said signals substantially independent of said intensity.
  • Apparatus according to claim 10 comprising also means responsive to'the electric potential of said grid and modifying the signals fed from said photo-electric cells to said computer in a manner such as to render said signals substantially independent of said intensity.

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  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Scanning Arrangements (AREA)
  • Projection-Type Copiers In General (AREA)
  • Color Television Image Signal Generators (AREA)
  • Control Of Exposure In Printing And Copying (AREA)
  • Fax Reproducing Arrangements (AREA)
US451466A 1953-08-25 1954-08-23 Colour printing Expired - Lifetime US2842610A (en)

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GB23459/53A GB738118A (en) 1953-08-25 1953-08-25 Improvements relating to colour printing

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US2842610A true US2842610A (en) 1958-07-08

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US654408A Expired - Lifetime US2993953A (en) 1953-08-25 1957-04-22 Colour or tonal reproduction

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US654408A Expired - Lifetime US2993953A (en) 1953-08-25 1957-04-22 Colour or tonal reproduction

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US (2) US2842610A (enrdf_load_stackoverflow)
DE (2) DE957012C (enrdf_load_stackoverflow)
FR (2) FR1111167A (enrdf_load_stackoverflow)
GB (2) GB738118A (enrdf_load_stackoverflow)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2962545A (en) * 1956-09-19 1960-11-29 Fernseh Gmbh Automatic flying spot scanner light intensity control
US2976349A (en) * 1957-06-10 1961-03-21 N E A Services Inc Method and apparatus for making color-corrected separations
US2981791A (en) * 1957-03-25 1961-04-25 Technicolor Corp Printing timer for making color positives on film
US2993954A (en) * 1958-09-29 1961-07-25 Crosfield J F Ltd Colour or tonal reproduction
US2993953A (en) * 1953-08-25 1961-07-25 Crosfield J F Ltd Colour or tonal reproduction
US3041932A (en) * 1957-09-24 1962-07-03 Hunter Penrose Ltd Photographic colour reproduction apparatus
US3100815A (en) * 1959-04-29 1963-08-13 Newspaper Entpr Ass Inc Apparatus for producing color separation negatives and the like
US3115807A (en) * 1960-06-17 1963-12-31 Logetronics Inc Electronic masking
US3745234A (en) * 1971-07-13 1973-07-10 Gaf Corp Video reproduction system for photographic and other images
US4134668A (en) * 1975-10-09 1979-01-16 Coburn Technology, Inc. Apparatus for image reproduction and image creation
US4227207A (en) * 1977-04-27 1980-10-07 The Rank Organisation Limited CRT film scanner with compensation for local brightness variations of scanning beam
US4281049A (en) * 1978-06-16 1981-07-28 Hoechst Aktiengesellschaft Color separation transparency and process for the preparation thereof
DE3820799A1 (de) * 1987-06-19 1988-12-29 Fuji Photo Film Co Ltd Fotografisches kopiergeraet

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB855895A (en) * 1957-03-11 1960-12-07 Crosfield J F Ltd Improvements in or relating to colour printing

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Publication number Priority date Publication date Assignee Title
US2434651A (en) * 1943-10-30 1948-01-20 Standard Oil Dev Co Stabilized xylidine and process for preparing same
US2605348A (en) * 1948-03-10 1952-07-29 Time Inc Color separation negative
US2691696A (en) * 1950-10-27 1954-10-12 Eastman Kodak Co Electrooptical unsharp masking in color reproduction
US2740828A (en) * 1951-12-29 1956-04-03 Rca Corp Color correction systems

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NL202464A (enrdf_load_stackoverflow) * 1941-07-25
US2710889A (en) * 1953-01-21 1955-06-14 Edward Stern & Company Inc Color reproduction
DE1072479B (enrdf_load_stackoverflow) * 1953-08-25 1959-12-31
US2757571A (en) * 1953-09-15 1956-08-07 Hazeltine Research Inc Photographic color printer
GB753340A (en) * 1953-11-13 1956-07-25 Ilford Ltd Improvements in or relating to the production of records of objects or pictures by scanning processes
US2799722A (en) * 1954-04-26 1957-07-16 Adalia Ltd Reproduction with localized corrections
US2790844A (en) * 1954-05-11 1957-04-30 Adalia Ltd Color correction selector

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2434651A (en) * 1943-10-30 1948-01-20 Standard Oil Dev Co Stabilized xylidine and process for preparing same
US2605348A (en) * 1948-03-10 1952-07-29 Time Inc Color separation negative
US2691696A (en) * 1950-10-27 1954-10-12 Eastman Kodak Co Electrooptical unsharp masking in color reproduction
US2740828A (en) * 1951-12-29 1956-04-03 Rca Corp Color correction systems

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2993953A (en) * 1953-08-25 1961-07-25 Crosfield J F Ltd Colour or tonal reproduction
US2962545A (en) * 1956-09-19 1960-11-29 Fernseh Gmbh Automatic flying spot scanner light intensity control
US2981791A (en) * 1957-03-25 1961-04-25 Technicolor Corp Printing timer for making color positives on film
US2976349A (en) * 1957-06-10 1961-03-21 N E A Services Inc Method and apparatus for making color-corrected separations
US3041932A (en) * 1957-09-24 1962-07-03 Hunter Penrose Ltd Photographic colour reproduction apparatus
US2993954A (en) * 1958-09-29 1961-07-25 Crosfield J F Ltd Colour or tonal reproduction
US3100815A (en) * 1959-04-29 1963-08-13 Newspaper Entpr Ass Inc Apparatus for producing color separation negatives and the like
US3115807A (en) * 1960-06-17 1963-12-31 Logetronics Inc Electronic masking
US3745234A (en) * 1971-07-13 1973-07-10 Gaf Corp Video reproduction system for photographic and other images
US4134668A (en) * 1975-10-09 1979-01-16 Coburn Technology, Inc. Apparatus for image reproduction and image creation
US4227207A (en) * 1977-04-27 1980-10-07 The Rank Organisation Limited CRT film scanner with compensation for local brightness variations of scanning beam
US4281049A (en) * 1978-06-16 1981-07-28 Hoechst Aktiengesellschaft Color separation transparency and process for the preparation thereof
DE3820799A1 (de) * 1987-06-19 1988-12-29 Fuji Photo Film Co Ltd Fotografisches kopiergeraet

Also Published As

Publication number Publication date
DE1072479B (enrdf_load_stackoverflow) 1959-12-31
GB835111A (en) 1960-05-18
FR1111167A (fr) 1956-02-23
FR1210640A (fr) 1960-03-09
GB738118A (en) 1955-10-05
DE957012C (de) 1957-01-24
US2993953A (en) 1961-07-25

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