Automatic color subject failure correction with illuminant discrimination for photographic printers

Claim 2

In a photographic printer, apparatus for controlling the exposure of print material to N selected wavelengths of radiation in the printing beam, and apparatus comprising: a. means responsive to the intensity of the N respective wavelengths of radiation in the printing beam of the photographic printer for producing N respective actuating signals after N time delays, measured from the time that the printing beam commences to expose the print material, that are dependent upon the intensity of said N respective wavelengths of radiation; b. first means responsive to the N actuating signals for terminating the exposure of the print material to the N respective wavelengths of radiation in the printing beam as each of the N actuating signals are produced; c. second means responsive to each of the N actuating signals, as they are produced in time, for shortening the time delays before the production of the remaining actuating signals to lower the spectral correction in the printing beam of the photographic printer; and d. third means responsive to the occurrence of the N actuating signals in a predetermined time sequence for lengthening the time delay before the production of the remaining actuating signals to provide a high degree of spectral correction in the printing beam of the photographic printer.

Claim 3

The apparatus of claim 1 wherein said intensity responsive means further comprises: a. N photosensors, said photosensors being responsive to the intensity of N respective wavelengths of radiation in the printing beam of the photographic printer for producing N first signals each having a magnitude dependent upon the intensity of a respective wavelength; and b. N time delay means each having an input terminal connected to a respective one of said photosensors and each having an output terminal, each of said time delay means being responsive to the respective first signal produced by the photosensor connected to its input terminal for producing an actuating signal at said output terminal after a time delay dependent upon the magnitude of the photocurrent signal.

Claim 4

a second pair of interconnecting circuits connected between the green color responsive photosensor and the input terminals of the red and blue time delaY means, each interconnecting circuit including a normally open switch;

Claim 5

a second pair of interconnecting circuits connected between the green color responsive photosensor and the input terminals of the red and blue time delaY means, each interconnecting circuit including a normally open switch;

Claim 6

a third pair of interconnecting circuits connected between the blue color responsive photosensor and the input terminals of the red and green time delay means, each interconnecting circuit including a normally open switch; and

Claim 7

a third pair of interconnecting circuits connected between the blue color responsive photosensor and the input terminals of the red and green time delay means, each interconnecting circuit including a normally open switch; and

Claim 8

The apparatus of claim 2 wherein said first means further comprises: a. N movable color filters, each of said color filters having the property of terminating the exposure of the print material to one of said N respective wavelengths of radiation in the printing beam of the photographic printer; and b. N actuator means coupled to said N movable color filters and individually responsive to said N control signals for moving the respective movable color filters into the printing beam of the photographic printer.

Claim 9

The apparatus of claim 1 wherein said first means further comprises: a. N movable color filters, each of said color filters having the property of terminating the exposure of the print material to one of said N respective wavelengths of radiation in the printing beam of the photographic printer; and b. N actuator means coupled to said N color filters and individually responsive to said N control signals for moving the respective color filters into the printing beam of the photographic printer.

Claim 10

three switch control means respectively connected to the output terminals of the red, green and blue time delay means and responsive to the actuating signals produced by the corresponding time delay means to close the pair of normally open switches in that pair of interconnecting circuits connected to the corresponding color responsive photosensor and the other two time delay means.

Claim 11

three switch control means respectively connected to the output terminals of the red, green and blue time delay means and responsive to the actuating signals produced by the corresponding time delay means to close the pair of normally open switches in that pair of interconnecting circuits connected to the corresponding color responsive photosensor and the other two time delay means.

Claim 12

The apparatus of claim 2 wherein said second means further comprises means responsive to each of said N actuating signals, in the sequence in which they are produced, for connecting the first signal applied to the input terminal of the time delay means producing the control signal to the input terminals of the remaining time delay means.

Claim 13

The apparatus of claim 5 wherein said first means further comprises: a. N movable color filters, each of said color filters having the property of terminating the exposure of the print material to one of said N respective wavelengths of radiation in the printing beam of the photographic printer; and b. N actuator means coupled to said N movable color filters and individually responsive to said N control signals for moving the respective movable color filters into the printing beam of the photographic printer.

Claim 14

The apparatus of claim 2 wherein said N first signals are designated In, In 1, . . . I1, respectively, and further comprising: a. means responsive to an imbalance in the magnitudes of the first signals, represented by In > In 1 . . . > I1, for producing an illuminant correction signal representative of the imbalance in magnitude therebetween; and b. attenuating means responsive to said illuminant correction signal for attenuating the magnitude of the first signal I1 thereby lengthening the time delay before the production of the actuating signal by the time delay means responsive to the first signal I1.

Claim 15

In a photographic printer, exposure control apparatus comprising: a. N movable subtractive color filters, each of said color filters having the property of absorbing light of a respective one of N colors in the printing beam of the color printer; b. N photosensors, each of said photosensors being responsive to the intensity of a respective one of N wavelengths of light in the printing beam of the color printer for producing N photocurrent signals each having a magnitude dependent upon the intensity of the respective color; c. N time delay means each having an input terminal connected to a respective one of said photosensors and each having an output terminal, each of said time delay means being responsive to the respective photocurrent signal coupled to its input terminal for producing an actuating signal at its output terminal after a time delay dependent upon the magnitude of the photocurrent signal; d. N actuator means coupled respectively to said color filters and responsive to said actuating signals for moving said color filters into the printing beam of the color printer in a sequence dependent upon the sequence in which the N actuating signals are produced; and e. color subject failure correction means responsive to each of said N actuating signals, in the sequence in which they are produced, for coupling the corresponding N photocurrent signals that are applied to the input terminals of each of the N time delay means to the input terminals of the remaining N - 1 time delay means to shorten the time period between the occurrences of the N actuating signals to lower the color correction in the printing beam of the color printer.

Claim 16

In a photographic printer, exposure control apparatus comprising: a. N movable subtractive color filters, each of said color filters having the property of absorbing light of a respective one of N colors in the printing beam of the color printer; b. N photosensors, each of said photosensors being responsive to the intensity of a respective one of N wavelengths of light in the printing beam of the color printer for producing N photocurrent signals each having a magnitude dependent upon the intensity of the respective color; c. N time delay means each having an input terminal connected to a respective one of said photosensors and each having an output terminal, each of said time delay means being responsive to the respective photocurrent signal coupled to its input terminal for producing an actuating signal at its output terminal after a time delay dependent upon the magnitude of the photocurrent signal; d. N actuator means coupled respectively to said color filters and responsive to said actuating signals for moving said color filters into the printing beam of the color printer in a sequence dependent upon the sequence in which the N actuating signals are produced; and e. color subject failure correction means responsive to each of said N actuating signals, in the sequence in which they are produced, for coupling the corresponding N photocurrent signals that are applied to the input terminals of each of the N time delay means to the input terminals of the remaining N - 1 time delay means to shorten the time period between the occurrences of the N actuating signals to lower the color correction in the printing beam of the color printer.

Claim 17

The apparatus of claim 8 wherein said color subject failure correction means further comprises: a. N interconnecting circuits connected between each of the N photosensors, respectively, and the input terminals of the remaining N - 1 time delay means, each interconnecting circuit including a normally open switch; and b. N switch control means respectively connected to the output terminals of the N time delay means and responsive to the N actuating signals, respectively, to close the N normally open switches in the interconnecting circuit connected to the input terminals of the remaining N - 1 time delay means.

Claim 18

The apparatus of claim 9 wherein said N photocurrent signals are designated In, In 1, . . . I1, respectively, and further comprising: a. illuminant discriminator means responsive to an imbalance in the magnitudes of the N photocurrent signals, represented by In > In l . . . > I1, for producing an illuminant correction signal related to the imbalance in the magnitudes of the photocurrent signals and indicative of a detected illuminant failure negative; and b. attenuating means responsive to the illuminant correction signal for attenuating the photocurrent I1 to thereby lengthen the time period before the subtractive color filter associated with the photocurrent signal I1 is moved into the printing beam of the color printer.

Claim 19

The apparatus of claim 8 wherein said N photocurrent signals are designated In, In 1, . . . I1, respectively, and further comprising: a. illuminant discriminator means responsive to an imbalance in the magnitudes of the N photocurrent signals, represented by In > In l . . . > I1, for producing an illuminant correction signal related to the imbalance in the magnitudes of the photocurrent signals and indicative of a detected illuminant failure negative; and b. attenuating means responsive to the illuminant correction signal for attenuating the photocurrent I1 to thereby lengthen the time period before the subtractive color filter associated with the photocurrent signal I1 is moved into the printing beam of the color printer.

Claim 20

In a color printer, exposure control apparatus comprising: a. three movable subtractive color filters, said color filters having the property of absorbing red, green and blue light, respectively; b. three photosensors, said photosensors being respectively responsive to the intensity of red, green and blue light in the printing beam of the color printer for producing three photocurrent signals, designated Ir, Ig and Ib, each having a magnitude dependent upon the intensity of each respective color; c. three time delay means, respectively designated red, green and blue, each having an input terminal connected to a respective one of said photosensors and each having an output terminal, said time delay means being responsive to the respective photocurrent signal connected to its input terminal for producing an actuating signal at said output terminal after a time delay dependent upon the magnitude of the applied photocurrent signal; d. three actuator means individually coupled to said filters and responsive to said actuating signals for moving said color filters into the printing beam of the color printer in a sequence dependent upon the sequence in which the three actuating signals are produced; and e. color subject failure correction means responsive to each one of the three actuating signals, in the sequence in which they are produced, for shortening the time delay before the production of the remaining actuating signals to lower the color correction of the printing beam of the photographic printer, said color subject failure correction means further comprising:

Claim 21

In a color printer, exposure control apparatus comprising: a. three movable subtractive color filters, said color filters having the property of absorbing red, green and blue light, respectively; b. three photosensors, said photosensors being respectively responsive to the intensity of red, green and blue light in the printing beam of the color printer for producing three photocurrent signals, designated Ir, Ig and Ib, each having a magnitude dependent upon the intensity of each respective color; c. three time delay means, respectively designated red, green and blue, each having an input terminal connected to a respective one of said photosensors and each having an output terminal, said time delay means being responsive to the respective photocurrent signal connected to its input terminal for producing an actuating signal at said output terminal after a time delay dependent upon the magnitude of the applied photocurrent signal; d. three actuator means individually coupled to said filters and responsive to said actuating signals for moving said color filters into the printing beam of the color printer in a sequence dependent upon the sequence in which the three actuating signals are produced; and e. color subject failure correction means responsive to each one of the three actuating signals, in the sequence in which they are produced, for shortening the time delay before the production of the remaining actuating signals to lower the color correction of the printing beam of the photographic printer, said color subject failure correction means further comprising:

Claim 22

The apparatus of claim 12 further comprising: a. illuminant discriminator means responsive to an imbalance in the magnitudes of the red, green and blue photocurrent signals, the imbalance represented by Ib > Ig > Ir, for producing an illuminant correction signal indicative of a detected illuminant failure negative; and b. attenuating means connected between the red photosensor and the input terminal of the red time delay means and between the green photosensor and the input terminal of the green time delay means, said attenuating means being responsive to the illuminant correction signal for attenuating the photocurrents Ir and Ig to lengthen the time period before the corresponding control signals are produced by the red and green time delay means.