Photographic copying arrangement with improved color compensation

Claim 2

In photographic apparatus for making at least one color copy of a photo originaL on photosensitive material, in combination, light source means for illuminating said photosensitive material through said original in a first, second and third color; a first, second and third color channel including, respectively, first, second and third photoreceiver means for receiving light corresponding to light falling on said photosensitive material in said first, second and third color and furnishing, respectively, a first, second and third total color signal corresponding to the total quantity of light received respectively in said first, second and third color; first second and third comparing means comparing said first, second and third color signals, respectively, to a reference signal and furnishing, respectively, a first, second and third terminating signal when the so compared total color signal has a predetermined relationship to said reference signal; terminating means for terminating the exposure and the corresponding color in response to each of said terminating signals; means furnishing a density signal corresponding to the density of said original in a selected one of said colors; and means for connecting said means for furnishing a density signal to the corresponding one of said comparing means, whereby the furnishing of the corresponding one of said terminating signals depends at least in part upon said density signal.

Claim 3

A photographic arrangement as set forth in claim 1, wherein said means for furnishing a density signal comprise means for furnishing a first, second and third density signal corresponding, respectively, to the density of said original in said first, second and third color; and wherein said means for connecting said means for furnishing a density signal to said comparing means comprise means for connecting said first, second and third means for furnishing a density signal to said first, second and third comparing means respectively.

Claim 4

A photographic arrangement as set forth in claim 1, wherein said means for furnishing a density signal comprise means for furnishing a density signal corresponding to the difference in density of said original in said selected one of said colors and the corresponding density of a calibrating original.

Claim 5

In photographic apparatus for making at least one color copy of a color original on photosensitive material, in combination, light source means for shining light in at least a first color through said original; photoelectric transducing means for receiving said light after passing through said original and furnishing a corresponding photocurrent; first circuit means responsive to said photocurrent and operative, prior to the start of exposure of said photosensitive material, for furnishing a density signal corresponding to the density of said original in said color; means for storing said density signal thereby furnishing a stored density signal; additional circuit means connectable to said first circuit means at the start of exposure of said photosensitive material, for modifying said first circuit means in such a manner that said first circuit means furnishes a total color signal corresponding to the total quantity of light in said color received by said photoelectric transducing means from the start of exposure of said photosensitive material; means for furnishing a reference signal varying at least in part in dependence upon said stored density signal; comparing means for comparing said total color signal to said reference signal and furnishing a terminating signal when said total color signal has a predetermined relationship to said reference signal; and means for terminating the exposure in said color upon receipt of said terminating signal.

Claim 6

In photographic apparatus for making at least one color copy of a color original on photosensitive material, in combination, light source means for shining light in at least a first color through said original; photoelectric transducing means for receiving said light after passing through said original and furnishing a corresponding photocurrent; first circuit means responsive to said photocurrent and operative, prior to the start of exposure of said photosensitive material, for furnishing a density signal corresponding to the density of said original in said color; means for storing said density signal thereby furnishing a stored density signal; additional circuit means connectable to said first circuit means at the start of exposure of said photosensitive material, for modifying said first circuit means in such a manner that said first circuit means furnishes a total color signal corresponding to the total quantity of light in said color received by said photoelectric transducing means from the start of exposure of said photosensitive material; means for furnishing a reference signal varying at least in part in dependence upon said stored density signal; comparing means for comparing said total color signal to said reference signal and furnishing a terminating signal when said total color signal has a predetermined relationship to said reference signal; and means for terminating the exposure in said color upon receipt of said terminating signal.

Claim 7

A photographic arrangement as set forth in claim 4, wherein said first circuit means comprise an operational amplifier having a negative feedback resistor; and wherein said additional circuit means comprise a capacitor, whereby said operational amplifier is an integrating amplifier starting at the beginning of said exposure time.

Claim 8

A photogRaphic apparatus for making at least one color copy of a color original on photosensitive material, in combination, light source means for shining light through said original in a first, second and third color; first, second and third color channel means having, respectively, a first, second and third photoelectric transducing element each for receiving light in a corresponding one of said colors after having passed through said original and furnishing, respectively, a first, second and third photocurrent corresponding thereto, first, second and third operational amplifier means each having an input connected to the corresponding on of said photoelectric transducing elements and each having a negative feedback circuit, each of said negative feedback circuits comprising a first resistor, a resistor-capacitor circuit, and selector switch means for switching from said first resistor to said resistor-capacitor circuit substantially simultaneously with the start of exposure of said photosensitive material, said first, second and third operational amplifier means furnishing, respectively, a first, second and third density signal corresponding, respectively, to the density of said original and said first, second and third color priot to the start of exposure of said photosensitive material and a first, second and third total color signal corresponding to the total quantity of light received, respectively, in said first, second and third color by said photosensitive material following said start of said exposure; storage means connected to said first, second and third operational amplifier means for storing said first, second and third density signals prior to said start of said exposure and furnishing a corresponding first, second and third stored density signal during said exposure; first, second and third comparing means for comparing said first, second and third total color signals, respectively, to a reference signal varying in dependence on said first, second and third stored density signals, respectively, and furnishing, respectively, first, second and third terminating signals when the so compared total color signal has a predetermined relationship to said reference signal; and terminating means for terminating the exposure in the corresponding color upon receipt of said terminating signal.

Claim 9

A photogRaphic apparatus for making at least one color copy of a color original on photosensitive material, in combination, light source means for shining light through said original in a first, second and third color; first, second and third color channel means having, respectively, a first, second and third photoelectric transducing element each for receiving light in a corresponding one of said colors after having passed through said original and furnishing, respectively, a first, second and third photocurrent corresponding thereto, first, second and third operational amplifier means each having an input connected to the corresponding on of said photoelectric transducing elements and each having a negative feedback circuit, each of said negative feedback circuits comprising a first resistor, a resistor-capacitor circuit, and selector switch means for switching from said first resistor to said resistor-capacitor circuit substantially simultaneously with the start of exposure of said photosensitive material, said first, second and third operational amplifier means furnishing, respectively, a first, second and third density signal corresponding, respectively, to the density of said original and said first, second and third color priot to the start of exposure of said photosensitive material and a first, second and third total color signal corresponding to the total quantity of light received, respectively, in said first, second and third color by said photosensitive material following said start of said exposure; storage means connected to said first, second and third operational amplifier means for storing said first, second and third density signals prior to said start of said exposure and furnishing a corresponding first, second and third stored density signal during said exposure; first, second and third comparing means for comparing said first, second and third total color signals, respectively, to a reference signal varying in dependence on said first, second and third stored density signals, respectively, and furnishing, respectively, first, second and third terminating signals when the so compared total color signal has a predetermined relationship to said reference signal; and terminating means for terminating the exposure in the corresponding color upon receipt of said terminating signal.

Claim 10

A photographic arrangement as set forth in claim 6, wherein each of said negative feedback circuits further comprise adjusting means for adjusting the impedence of said negative feedback circuit means for different formats of said original.

Claim 11

A photographic arrangement as set forth in claim 7, wherein each of said adjusting means comprises a trimmer potentiometer.

Claim 12

A photographic arrangement as set forth in claim 6, further comprising a first, second and third logarithmic amplifier connected, respectively, to the output of said first, second and third operational amplifier means.

Claim 13

A photographic arrangement as set forth in claim 9, further comprising first, second and third summing amplifier means each having a first input connected to the output of a corresponding one of said logarithmic amplifiers and a second input; wherein said first, second and third color channel means further comprise first, second and third means for furnishing a first, second and third sensitivity signal, respectively varying, at least in part, as a function of the sensitivity of said photosensitive material in the corresponding one of said colors; further comprising means for connecting each of said means for furnishing a sensitivity signal to the second input of the corresponding one of said summing amplifier means.

Claim 14

A photographic arrangement as set forth in claim 10, wherein said first comparing means comprise a comparator having a first input connected to the output of said first summing amplifier means, and a second input; and wherein said means for furnishing a first stored density signal comprise first sample and hold amplifier means having an input connected to the outpuT of said first summing amplifier means when said selector switch means connects said first resistor to said first operational amplifier means, and an output for furnishing said stored density signal during the exposure time; further comprising means for connecting the output of said sample and hold amplifier means to said second input of said comparator.

Claim 15

A photographic arrangement as set forth in claim 11, further comprising means for furnishing a reference density signal indicative of the density of a calibrating original; and means for connecting said means for furnishing a reference density signal to said input of said sample and hold amplifier means.

Claim 16

A photographic arrangement as set forth in claim 12, wherein said means for connecting said output of said sample and hold amplifier means to said second input of said comparator comprise a first potentiometer having a first terminal connected to said output of said sample and hold amplifier means, a second terminal connected to the corresponding terminal of a second and third potentiometer respectively connected in said second and third color channels and a wiper arm; and undercorrection summing amplifier means having a first input connected to said wiper arm, a second input connected to said second end terminal of said potentiometer and an output for furnishing a color undercorrection signal; and additional summing amplifier means having a first input connected to said output of said undercorrection summing amplifier means and an output connected to said second input of said comparator.

Claim 17

A photographic arrangement as set forth in claim 13, wherein said additional summing amplifier means has a second input; further comprising a first and second slope signal potentiometer adjustable for different density ranges of the originals, each having a wiper arm for furnishing a slope signal having the same amplitude but opposite polarity of the slope signal furnished by the other of said potentiometers; slope summing amplifier means having a first input connected to said wiper arm of said first potentiometer of said means for connecting said output of said sample and hold amplifier means to said second input of said comparator, a second input connected to said second end terminal of said first potentiometer and an output connected to said first slope signals potentiometer; and inverter means interconnected between the output of said slope summing amplifier means and said second slope signal potentiometer; and slope signal switch means operable in dependence on the polarity of said signal at the output of said slope summing amplifier means for connecting said wiper arm of said first or said second slope signal potentiometer to said second input of said additional summing amplifier means.