Abstract:
Light from a light source is transmitted through an original at a scanning station to a light detector. A rotating scanning disk located in the path of this light is provided with equiangularly spaced radial scanning slots. A light-blocking plate located between the light source and the scanning disk defines a scanning slot extending transverse to the transport direction of the original. Light passing through both the original and the transverse scanning slot is projected as a slot image onto the surface of the scanning disk. The radial slots and the transverse slot cooperate to define a scanning spot which sweeps across the original, and thereby performs one line-scan operation, as one radial slot sweeps across the slot image on the scanning disk. The angular span between adjoining radial slot is greater than that of the slot image so that, during intermediate intervals between successive line-scan operations, light transmitted through the original does not reach the light detector. During the intermediate time intervals, reference light from the light source is directed onto the light detector along a reference light path not passing through the original. An evaluating circuit receives both the signal produced by the light detector during a line-scan operation and the signal produced during the preceding or subsequent intermediate time interval, and in dependence upon the values of both signals produces a signal whose value indicates the density of the extreme-density scanned spot on the scanned original.
Abstract:
Apparatus for the determination of light transmissivity of film frames preparatory to the making of prints in a copying machine has a plate-like locating device for successive film frames, a light source at one side of the locating device, a group of photosensitive signal-generating elements at the other side of the locating device, and a diaphragm which is interposed between the locating device and photosensitive elements and has a hollow truncated pyramid, plate-like partitions and tubular components which confine light passing through the film frame on the locating device in such a way that a centrally located photosensitive element receives light from the entire film frame and all of the light which has passed through the central field of the frame, whereas each of the other photosensitive elements receives only that light which has passed through a single one of four L-shaped peripheral fields surrounding the central field of the frame. Light which reaches the centrally located element passes through the pyramid as well as around the pyramid. On the other hand, light which reaches the other photosensitive elements passes from the corresponding peripheral fields and thereupon through the tubular components of the diaphragm. Consequently, the signal which is transmitted by the centrally located element is indicative of transmissivity of the entire frame, and the signals transmitted by the other elements are indicative solely of transmissivity of the respective peripheral frames.
Abstract:
Light containing blue, green and red radiation is passed through a colored original which is to be printed on color copy material. The transmitted light is spread out into a color spectrum which extends across a first wavelength range generally corresponding to the blue portion of the spectrum, a second wavelength range generally corresponding to the green portion of the spectrum and a third wavelength range generally corresponding to the red portion of the spectrum. The intensity of the transmitted light is measured throughout the spectrum and average of the resulting raw intensities are taken oer each of a series of wavelength intervals which are much shorter than the first, second and third ranges. The copy material has a gamma value for each wavelength interval and such gamma value represents the spectral sensitivity of the copy material in the corresponding interval. The average intensity for each wavelength interval is multiplied by the respective gamma value to yield a corrected intensity. The corrected intensities for each wavelength range are summed to generate first, second and third sums corresponding to the first, second and third ranges and respectively representing the blue, green and red densities of the original. The first, second and third sums are used to calculate the respective amounts of blue, green and red light required to print the original with a neutral gray density.
Abstract:
A strip of exposed and developed color film is transported through a transparency measuring system. The transparency of each frame of the film strip in the three primary colors is measured at a multiplicity of regions. The transparency values are converted to density values which are processed to generate a set of data characteristic of the film strip and indicative of the color compositions of the scanned regions. The characteristic set of data and the density values for the individual regions are used to determine whether or not a respective region contains a color dominant. For each frame, the amounts of copying light in the primary colors are established from the density values of those regions which are free of color dominants and have a neutral gray color composition. The amount of copying light in each of the three primary colors is calculated so that the regions of the original having a neutral gray color composition are copied neutral gray. In order to ensure that the copying material registers the copying light in the same manner as the measuring system registers the transparency measuring light, the measuring light is filtered so as to match the spectral sensitivity of the measuring system in each primary color to the spectral sensitivity of the copying material in the same color.
Abstract:
A series of exposed and developed film strips having various lengths are spliced end-to-end for copying. The resulting band passes through a density measuring station in which the densities of the negatives are measured in the three primary colors and next through a magazine of variable capacity in which a portion of the band accumulates before entering a negative copying station including an exposure control device which regulates the exposures of the negatives on the measured basis of the density values. To insure that values derived from a selected strip are transferred to the exposure control unit when the strip enters the copying station, the splice immediately downstream of the selected strip is arrested in the density measuring station. The band continues to be drawn through the copying station so that the portion which has accumulated in the magazine is fully withdrawn. The portion of the band between the arrested splice and a splice sensor in the copying station has a known length. The arrested junction is now released and a length measuring device begins to measure the length of the portion travelling through the copying station. If the sensor detects a splice when the measured length equals the known length, this splice is the previously arrested splice.
Abstract:
A method of copying a colored original involves measuring the transparency of localized regions of the original in each of the three primary colors. Three localized transparency ratios for each region are formed from the transparency values for the different colors. Three corresponding average transparency ratios for the original as a whole are computed from the localized transparency ratios. Each average transparency ratio is compared with a statistical average of similar ratios obtained from a large number of average originals. If an average transparency ratio of the original to be copied deviates from the corresponding statistical average by more than a predetermined amount, the number of each of the localized transparency ratios lying inside and outside of a predetermined range about the corresponding average transparency ratio of the original is counted. When the number outside of a predetermined range exceeds the number inside, a color dominant is assumed to be present in the original. Otherwise, a color tinge is assumed to be present. The original is copied using a correction factor which depends upon whether a color dominant or a color tinge is present. An alternative method summing the differences between the localized transparency ratios and the respective average transparency ratios of the original is also presented.
Abstract:
A negative whose printability is to be automatically ascertained is subdivided into a central zone, a foreground zone, and a background zone. Whole-zone density signals are produced for the foreground and background zones, and the central zone is scanned to generate a maximum-density signal indicating the density of the maximum-density point within the central zone. The negative is rejected for being underexposed when both of two conditions are met: first, the larger of the foreground and background whole-zone density signals fails to exceed a first limit value; and second, the difference between the central-zone maximum-density signal, on the one hand, and the smaller of the foregound and background whole-zone density signals, on the other hand, fails to exceed a second limit value. The negative is rejected as overexposed when the average of the foreground and background whole-zone density signals fails to exceed a third limit value, irrespective of the density of the central zone. The negative is rejected as containing a meaningless motif, e.g., an adhesive sticker applied to the negative, when the central-zone maximum-density signal exceeds a fourth limit value, the density corresponding to the fourth limit value being higher than the density corresponding to the third limit value.
Abstract:
Successive frames of a web of photographic color film are subjected to objective examination during transport through an automatic evaluating circuit which may constitute a discrete prereader or a prereader which is integrated into a copying machine upstream of the copying station. The prereader furnishes signals which represent color and/or density correction data for reproduction of those film frames which can be properly copied only with a setting of exposure controls which deviates from the average setting for copying of the majority of film frames. The objective examination of all film frames is followed by a subjective examination which is performed by an attendant who inspects at least some of those film frames whose examination by the prereader resulted in the generation of correction signals. The attendant inspects the film frames at the copying station or at a second station which is located immediately downstream of a discrete prereader, and the attendant simultaneously observes the corresponding correction signals which are furnished by the evaluating circuit and are displayed close to the copying station or in register with film frames at the second station. The attendant can approve, modify or cancel the correction signals, and can also initiate the generation of additional signals, e.g., to identify those film frames which are unfit for copying.
Abstract:
An automatic prereader for exposed and developed frames of a web of spliced-together photographic color films is preceded by a first station and followed by a second station at the first of which groups of successive frames are subjected to a first subjective examination by an attendant and at the second of which some of the frames are subjected to renewed subjective examination by the same attendant. The attendant actuates one or more pushbuttons upon examination of frames at the first station to produce signals which denote improperly oriented frames, frames which were exposed in artificial light and/or frames which are unfit for copying. Such signals are used to modify signals which are furnished by the automatic prereader. The modified and unmodified signals which are furnished by the prereader are examined for intensity, and those signals whose intensity is outside of a preselected range are displayed at the second station so that the attendant can observe such signals simultaneously with observation of the respective film frames and is in a position to initiate the generation of additional signals which are used to modify or erase the corresponding signals from the prereader before the signals are transmitted to the exposure controls of a copying machine.