Automatic control of color correction of photographic printers

Claim 2

In a photographic printer, exposure control apparatus for controlling the degree of color correction provided in the printing beam of the photographic printer in response to first and second radiation signals generated respectively by first and second radiation sensitive devices, each of the radiation sensitive devices being sensitive to radiation of a different wavelength in said printing beam, said exposure control apparatus comprising: a. means responsive to the first and second radiation signals generated by said first and second radiation sensitive devices for producing a third signal having a periodic wave form of first and second amplitude, the durations of the first and the second amplitudes being dependent upon the first and second radiation signals; and b. means responsive to the first amplitude of the periodic wave form of the third signal for providing a high degree of color correction in the printing beam of the color printer for the duration of the first amplitude and responsive to the second amplitude of the periodic wave form of the third signal for providing a low degree of color correction in the printing beam of the color printer for the duration of the second amplitude.

Claim 3

In a photographic printer, exposure control apparatus for controlling the degree of color correction provided in the printing beam of the photographic printer in response to radiation signals generated by a plurality of radiation sensitive devices, each of the radiation sensitive devices being sensitive to radiation of a different wavelength in said printing beam, said exposure control apparatus comprising: a. means responsive to at least two radiation signals for producing a first signal having an amplitude dependent upon the amplitudes of the two radiation signals; b. means responsive to the first signal for producing a first and a second control signal having first and second complementary periodic wave forms of first and second amplitudes, the durations of the first and second amplitudes being dependent upon the amplitude of the first signal; c. means responsive to the first amplitude of the periodic wave form of the first control signal for providing a high degree of color correction in the printing beam for a duration of the printing time of the photographic printer that is dependent upon the duration of The first amplitude; and d. means responsive to the first amplitude of the periodic wave form of the second control signal for providing a low degree of color correction in the printing beam for a duration of the printing time of the photographic printer that is dependent upon the duration of the first amplitude.

Claim 4

In a photographic printer, exposure control apparatus for controlling the degree of color correction provided in the printing beam of the photographic printer in response to radiation signals generated by a plurality of radiation sensitive devices, each of the radiation sensitive devices being sensitive to radiation of a different wavelength in said printing beam, said exposure control apparatus comprising: a. means responsive to at least two radiation signals for producing a first signal having an amplitude dependent upon the amplitudes of the two radiation signals; b. means responsive to the first signal for producing a first and a second control signal having first and second complementary periodic wave forms of first and second amplitudes, the durations of the first and second amplitudes being dependent upon the amplitude of the first signal; c. means responsive to the first amplitude of the periodic wave form of the first control signal for providing a high degree of color correction in the printing beam for a duration of the printing time of the photographic printer that is dependent upon the duration of The first amplitude; and d. means responsive to the first amplitude of the periodic wave form of the second control signal for providing a low degree of color correction in the printing beam for a duration of the printing time of the photographic printer that is dependent upon the duration of the first amplitude.

Claim 5

means responsive to the third signal for producing first and second control signals having first and second complementary, periodic, wave forms of first and second amplitudes, the duration of the first amplitudes of the wave forms of the first and second control signals being dependent upon the magnitude of the third signal,

Claim 6

means responsive to the third signal for producing first and second control signals having first and second complementary, periodic, wave forms of first and second amplitudes, the duration of the first amplitudes of the wave forms of the first and second control signals being dependent upon the magnitude of the third signal,

Claim 7

means responsive to the first amplitude of the wave form of the first control signal for determining said first and second exposure time periods as a function of the combined magnitudes of the first and second signals, and

Claim 8

means responsive to the first amplitude of the wave form of the first control signal for determining said first and second exposure time periods as a function of the combined magnitudes of the first and second signals, and

Claim 9

In a photographic printer, exposure control apparatus for controlling the exposure time periods of photographic print material to first and second wavelengths of light in the printing beam of the image to be printed in response to the intensities of the respective first and second wavelengths, said exposure control apparatus comprising: a. first means for exposing photographic print material to first and second wavelengths of light in the printing beam of the image to be printed; b. second means adapted to halt the exposure of the photographic print material to said first wavelength after a first exposure time period; c. third means adapted to halt the exposure of the photographic print material to the second wavelength after a second exposure time period; d. fourth means responsive to the intensities of said first and second wavelengths of light in the printing beam and for producing respective first and second signals each having a magnitude dependent upon the respective intensities of said first and second wavelengths; and e. fifth means responsive to the first and second signals for establishing the first and second exposure time periods of the second and third means, respectively, comprising:

Claim 10

In a photographic printer, exposure control apparatus for controlling the exposure time periods of photographic print material to first and second wavelengths of light in the printing beam of the image to be printed in response to the intensities of the respective first and second wavelengths, said exposure control apparatus comprising: a. first means for exposing photographic print material to first and second wavelengths of light in the printing beam of the image to be printed; b. second means adapted to halt the exposure of the photographic print material to said first wavelength after a first exposure time period; c. third means adapted to halt the exposure of the photographic print material to the second wavelength after a second exposure time period; d. fourth means responsive to the intensities of said first and second wavelengths of light in the printing beam and for producing respective first and second signals each having a magnitude dependent upon the respective intensities of said first and second wavelengths; and e. fifth means responsive to the first and second signals for establishing the first and second exposure time periods of the second and third means, respectively, comprising:

Claim 11

means responsive to the first amplitude of the wave form of the second control signal for independently determining said first and second exposure time periods from the magnitudes of the first and second signal, respectively.

Claim 12

means responsive to the first amplitude of the wave form of the second control signal for independently determining said first and second exposure time periods from the magnitudes of the first and second signal, respectively.

Claim 13

The apparatus of claim 3 wherein said second means and said third means further comprise first and second timing circuits, respectively, each having an input terminal and an output terminal and adapted to produce a first and second respective exposure terminating signal at each respective output terminal after first and second exposure time periods determined as a function of the magnitudes of the signals applied to the input terminals.

Claim 14

The apparatus of claim 4, and more particularly the fifth means thereof, wherein: a. said means responsive to the first amplitude of the wave form of the first control signal comprises a first plurality of signal conducting circuits adapted to be connected, in response to the first amplitude of the first control signal, between said fourth means and each respective input terminal of said timing circuits to separately apply the first signal to the timing circuit of said second means and the second signal to the timing circuit of said third means; and b. said means responsive to the first amplitude of the wave form of the second control signal comprises a further plurality of signal conducting circuits adapted to be connected, in response to the first amplitude of the second control signal, between said fourth means and every one of the input terminals of said timing circuits to apply the first and second signals simultaneously to the timing circuits of second and third means.

Claim 15

The apparatus of claim 5 wherein: a. said timing circuits of said second and third means, for the duration of the first amplitude of said first control signal, determine said first and second exposure time periods as a function of the magnitudes of said first and second signals; and b. said timing circuits of said second and third means, for the duration of the first amplitude of the second control signal, determine said first and second exposure time periods as a function of the combined magnitudes of the first and second signals.

Claim 16

In exposure control apparatus for a photographic printer comprising a plurality of filters, a plurality of photosensors corresponding to each one of said filters, each of said photosensors being sensitive to light of a different wavelength in the printing beam of said photographic printer for producing a first signal having a magnitude dependent upon the intensity of each wavelength of light, actuator means for controlling the individual insertion of each of said filters into said printing beam in response to an actuating signal, and timing means responsive to the first signals for producing each of the actuating signals, the improvement comprising: a. first means responsive to an imbalance in the magnitudes of the first signals for producing a second signal having a magnitude dependent upon the imbalance; b. second means responsive to the second signal for producing first and second control signals having complementary, periodic, wave forms of first and second magnitudes, the duration of the first magnitudes being dependent upon the magnitude of the second signal; c. third means responsive to the first magnitude of the first control signal for coupling each one of the photocurrent signals to a respective one of the timing means to produce said respective trigger signals after time delays dependent upon the magnitude of each individual first signal and the duration of the first amplitude of the first control signal; and d. fourth means responsive to the first amplitude of the second control signal for coupling each one of said first signals to every one of said timing means to produce said respective trigger signals simultaneously after a time delay dependent upon a combination of the magnitudes of all of the first signals and the duration of the first amplitude of the second control signal.

Claim 17

In exposure control apparatus for a photographic printer comprising a plurality of filters, a plurality of photosensors corresponding to each one of said filters, each of said photosensors being sensitive to light of a different wavelength in the printing beam of said photographic printer for producing a first signal having a magnitude dependent upon the intensity of each wavelength of light, actuator means for controlling the individual insertion of each of said filters into said printing beam in response to an actuating signal, and timing means responsive to the first signals for producing each of the actuating signals, the improvement comprising: a. first means responsive to an imbalance in the magnitudes of the first signals for producing a second signal having a magnitude dependent upon the imbalance; b. second means responsive to the second signal for producing first and second control signals having complementary, periodic, wave forms of first and second magnitudes, the duration of the first magnitudes being dependent upon the magnitude of the second signal; c. third means responsive to the first magnitude of the first control signal for coupling each one of the photocurrent signals to a respective one of the timing means to produce said respective trigger signals after time delays dependent upon the magnitude of each individual first signal and the duration of the first amplitude of the first control signal; and d. fourth means responsive to the first amplitude of the second control signal for coupling each one of said first signals to every one of said timing means to produce said respective trigger signals simultaneously after a time delay dependent upon a combination of the magnitudes of all of the first signals and the duration of the first amplitude of the second control signal.

Claim 18

The improvement of claim 7 wherein said third means comprises a high color correction circuit means and said fourth means comprises a low color correction circuit means.

Claim 19

The improvement of claim 7 wherein said third means comprises: a. first plurality of first signal conducting circuits including a plurality of switch means adapted to be closed, in response to the first amplitude of the first control signal, to conduct first signals between each one of said photosensors and each respective one of said timing means; and b. said fourth means comprises a second plurality of first signal conducting circuits including a like plurality of switch means adapted to be closed, in response to the first amplitude of the second control signal, to conduct each one of the first signals to every one of said timing means.

Claim 20

In exposure control apparatus for a photographic printer comprising a plurality of filters, a plurality of photosensors corresponding to each one of said filters, each of said photosensors being sensitive to light of a different wavelength in the printing beam of said photographic printer for producing a photocurrent signal having a magnitude dependent upon the density of each respective wavelength of light, actuator means for controlling the individual movement of each of said filters into said printing beam in response to an actuating signal, and timing means responsive to the photocurrent signals for producing each of the actuating signals, the improvement comprising: a. a first plurality of photocurrent signal conducting circuits adapted to connect each one of said pHotosensors to each respective one of said timing means to separately apply each of the photocurrent signals to each of said timing means, each of said first plurality of photocurrent signal conducting circuits further comprising a normally closed switch; b. a second plurality of photocurrent conducting circuits adapted to connect each one of said photosensors to every one of said timing means to simultaneously apply each of the photocurrent signals to all of said timing means, each of said second plurality of photocurrent signal conducting circuits further comprising a normally open switch; and c. means responsive to an imbalance in the magnitudes of the plurality of photocurrent signals for opening the first switches and closing the second switches for a time period dependent upon the degree of imbalance in the photocurrent signals.

Claim 21

In exposure control apparatus for a photographic printer comprising a plurality of filters, a plurality of photosensors corresponding to each one of said filters, each of said photosensors being sensitive to light of a different wavelength in the printing beam of said photographic printer for producing a photocurrent signal having a magnitude dependent upon the density of each respective wavelength of light, actuator means for controlling the individual movement of each of said filters into said printing beam in response to an actuating signal, and timing means responsive to the photocurrent signals for producing each of the actuating signals, the improvement comprising: a. a first plurality of photocurrent signal conducting circuits adapted to connect each one of said pHotosensors to each respective one of said timing means to separately apply each of the photocurrent signals to each of said timing means, each of said first plurality of photocurrent signal conducting circuits further comprising a normally closed switch; b. a second plurality of photocurrent conducting circuits adapted to connect each one of said photosensors to every one of said timing means to simultaneously apply each of the photocurrent signals to all of said timing means, each of said second plurality of photocurrent signal conducting circuits further comprising a normally open switch; and c. means responsive to an imbalance in the magnitudes of the plurality of photocurrent signals for opening the first switches and closing the second switches for a time period dependent upon the degree of imbalance in the photocurrent signals.

Claim 22

Exposure control apparatus for a photographic printer comprising at least three subtractive filters, photosensors corresponding to each of said filters and responsive to light of a different wavelength in the printing beam of said printer for producing three photocurrent signals, actuator means for controlling the individual movement of each of said filters into said printing beam, and timing means for determining the printing time prior to insertion of said filters into the printing beam in response to said photocurrent signals comprising: a. at least three respective high color correction circuit means responsive to each individual photocurrent signal for determining the printing time of each respective wavelength of light in the printing beam of the photographic printer; b. at least three low color correction circuit means responsive to each of said photocurrent signals for determining a single printing time for all of the wavelengths of light in said printing beam; and c. means responsive to an imbalance between the amplitudes of the photocurrent signals for determining the exposure time periods by either said high color correction circuit means or said low color correction circuit means, respectively.

Claim 23

Exposure control apparatus for a photographic printer comprising at least three subtractive filters, photosensors corresponding to each of said filters and responsive to light of a different wavelength in the printing beam of said printer for producing three photocurrent signals, actuator means for controlling the individual movement of each of said filters into said printing beam, and timing means for determining the printing time prior to insertion of said filters into the printing beam in response to said photocurrent signals comprising: a. at least three respective high color correction circuit means responsive to each individual photocurrent signal for determining the printing time of each respective wavelength of light in the printing beam of the photographic printer; b. at least three low color correction circuit means responsive to each of said photocurrent signals for determining a single printing time for all of the wavelengths of light in said printing beam; and c. means responsive to an imbalance between the amplitudes of the photocurrent signals for determining the exposure time periods by either said high color correction circuit means or said low color correction circuit means, respectively.

Claim 24

The exposure control apparatus of claim 11 further comprising timing means associated with each of said three subtractive color filters and a. said photocurrent signal responsive means is responsive to the amplitude of the photocurrent signals to produce a first and a second control signal having periodic complementary wave forms, each wave form having a first and a second amplitude, the first amplitude being dependent upon the relationship between the amplitudes of the photocurrent signals; b. said high color correction circuit means are responsive to the first amplitude of the first control signal to couple said three photocurrent signals individually to said three timing means so that the printing time of each of said wavelengths in the printing beam is dependent upon the amplitudes of each photocurrent and the duration of the first amplitude of the first control signal; and c. said three low color correction circuit means are responsive to the first amplitude of the second control signal for coupling each of said photocurrent signals to every one of said timing means so that said single printing time of said wavelengths in said printing beam is dependent upon an average of the amplitudes of all of said photocurrent signals and the duration of the first amplitude of the second control signal.

Claim 25

The exposure control apparatus of claim 12 wherein said three subtractive filters are operative to absorb red, green and blue light, respectively, in said printing beam and said photosensor means are responsive to the intensity of the red, green and blue light, respectively, in the printing beam to produce said three photocurrent signals each having an amplitude dependent upon each respective intensity.

Claim 26

The exposure control apparatus of claim 13 wherein said photocurrent signal responsive means further comprises: a. first means responsive to the difference between the amplitudes of the red and green photocurrent signals for producing a first difference signal having a first difference amplitude; b. second means responsive to the difference in the amplitudes of the green and blue photocurrent signals for producing a second difference signal having a second difference amplitude; c. third means for establishing a first reference signal having a reference period; and d. means responsive to the lower amplitude of the first and second difference signals and the period of the first reference signal for producing said first and second control signals having complementary, periodic, wave forms, the periods of which are equal to the period of the reference signal.