Abstract: Red, green and blue densities of a color negative are measured at a plurality of points thereon. The measured densities are normalized by a normalizing circuit so that the same levels of density signals can be obtained regardless of the gamma value and sensitivity of the negatives when the same subject matter is photographed under the same conditions. The normalized density signals are plotted in a chromaticity coordinate system and examined as to whether or not they fall within a given region defining a particular color in the chromaticity coordinate system. When the level of the normalized signals with respect to a given point falls within the given region, the point is determined to have the particular color defined by the region in the chromaticity coordinate system. When the color negative includes a predetermined number of points of the particular color, the exposure in a color printer is controlled to reproduce the particular color in a desirable condition.

Abstract: Red, green and blue densities of a color negative are measured at a plurality of points thereon. The measured densities are normalized by a normalizing circuit so that the same levels of density signals can be obtained regardless of the gamma value and sensitivity of the negatives when the same subject matter is photographed under the same conditions. The normalized density signals are plotted in a chromaticity coordinate system and examined as to whether or not they fall within a given region defining a polygon in the coordinate system. The coordinate system is a two dimensional coordinate system in which the axes thereof represent the combinations of two color densities among red, green and blue densities. When the level of the normalized signals with respect to a given point falls within the given region defined by the polygon, the point is determined to have the particular color.

Abstract: The densities of neighboring unit areas of a color photographic negative are measured in each of the primary colors and the results of measurements are compared with each other to ascertain the dimensions and boundaries of negative portions which exhibit dominant colors. Each such portion is considered in the selection of the amounts of copying light to the extent corresponding to a single unit area. The comparison is carried out by a computer which compares the results of measurements of neighboring unit areas, as considered in and at right angles to the direction of movement of the negative relative to the monitoring elements. A result of measurement is disregarded if it deviates from the result of measurement of a neighboring unit area by less than a preselected reference value which may but need not be different for each primary color.

Abstract: A hand-carriable, compact color meter for indicating proper amount of adjustment of color compensation filters interposed in the light path of a color printer for the compensation of color balance of the light illuminating a film or the slide set on the printer. The color meter includes an indicating lamp, a photocell to be exposed to the light passing through the film or slide, a plurality of optical color filters selectively disposed in front of the photocell to provide the photocell with spectral sensitivities corresponding to the spectral sensitivity of the printing paper, a plurality of fixed or variable resistors selectable in correspondence to the selection of the color filter, and an electric circuit for actuating the indicating lamp in accordance with the relationship between the output of the light measuring circuit and a reference voltage commensurate with the selected one of the resistors.

Abstract: Method and apparatus for detecting and controlling the concentration of active toner particles in a liquid developer comprising taking a sample or proportion of liquid developer and subjecting it to an electrostatic field, measuring the toner particle concentration influenced by the field and correcting the concentration of effective toner particles in the developer by restoring said concentration to an acceptable predetermined level, and further measuring the concentration of degraded toner particles left in the liquid developer to determine if the entire developer is to be replaced.

Abstract: A photometric device for measuring and displaying by digital means primary color densities of a color negative to be printed to determine densities of color compensating filters. Exposure time, including reciprocity effect compensation for the photographic paper, is displayed digitally and determined by density measurements of the projected image.A reference area of a color negative illuminated by light through color compensating filters is projected on the aperture of a probe which directs light through a light guide to a photodetector. The resulting photocurrents generate voltages amplified by a first and second variable gain linear amplifier. The second amplifier provides primary color and exposure density reference by means of gains stored by measurement of a standard negative. Digital display means is provided to display memory gains for accurately modifying or resetting reference gains.

Abstract: An apparatus for determining the color composition of the printing light of a photographic enlarger samples and measures the light within the intermediate diaphragm chamber of the objective lens. The light is sampled by inserting color-sensitized photoelectric transducers within the intermediate diaphragm chamber or inserting a light conducting means within the chamber between exposures for sampling and conducting the light outside of the chamber to external photoelectric transducer means, which determines the color content in any operative manner. The light conductor may be mounted on a slide together with an adjustable diaphragm for alternating inserting in the path of the printing light or the light conductor and a number of apertures of different cross-sections may be mounted on a rotary disk for optional insertion along the optical axis. The light conducting means includes a diffusing element within a light conducting and reflecting chamber.

Abstract: A color printer having three color filters is provided with a filter controller which controls the insertion time of the color filters to print a particular color such as a flesh color of a human figure into a preferable particular color of preferable color balance and density. The filter controller includes an arithmetic memory circuit which memorizes for three primary colors a relation between the color density of the particular color in the color original and the preferable insertion time of the color filters to print the particular color into the preferable particular color on the color paper.

Abstract: The color balance of color photographic printing paper is determined by making three successive exposures of separate portions of a sample sheet of printing paper through a neutral-color optical wedge of linear density gradient, each exposure consisting essentially of a different primary color of light of predetermined intensity and duration to selectively stimulate each of the three color-sensitive emulsion layers in the printing paper. The three images produced upon development provide a means for objective quantitative measurement of the relative responsiveness of each of the emulsion layers using a reflection densitometer to locate points of equal optical density, the relative linear displacement of the points providing color-balance correction factors. An easel is provided with a sliding carriage for positioning the sample sheet of printing paper in proper relationship to the optical wedge, which is fixed in place in an aperture in a light-proof cover.

Abstract: The color composition of printing light in a photographic enlarger is sampled by rotating a sampling duct between the original image holder and the objective lens. The duct has a thin elongated rectangular shape with a light diffusing aperture disposable in the printing light and with mirrored inside walls, which transmit a representative sample of the printing light to the outlet aperture, which is disposed in front of light measuring receivers. The receivers generate a signal which is processed to govern the insertion of filters in the light-mixing head of the enlarger to provide the desired color composition in the printing light. A convenient push control and actuating switch arrangement is provided to simplify insertion of the duct in the printing light before and its removal during the printing exposure.

Abstract: A method for determining the characteristics and amount of microscopic contaminants lodged on a photographed surface. An image enhanced full-color photographic negative and print are taken of the contaminated surface. Three black-and-white prints are developed subsequently from red, green and blue separation filter overlays of the color negative. Both the color and three monochromatic prints are then scanned to extract in digital form a profile of any contaminant possibly existing on the surface. The resulting profiles are electronically analyzed and compared with data already stored relating to known contaminants.

Abstract: An exposure control system for color printers having electro/optical means for spectral analysis of different types of original material for printing to determine different spectral coefficients for each material. Each coefficient is classified according to a reference range of values, each range being associated with a different original material. Photoelectric means are provided to determine the color densities of an original and a store stores sets of exposure parameters, each set being associated with a different original material. Automatic selection means responsive to the classification is provided to select whichever parameter set is associated with a coefficient reference range in which the coefficient has been classified during classification.

Abstract: A photo-reconnaissance/surveillance system in which the landscape to be sned is photographed on color film. The film is then developed in a highspeed processor and scanned by photosensors. Illuminations for the sensors is provided by a plurality of point sources of light. Colored filters e.g., a green filter and a blue filter, are alternately interposed between the light sources and the film. A logic circuit compares the transmission through the film for both light conditions and, thus, can detect the presence of a target, if the color signature of the target is known a priori.

Abstract: The device is housed in an enclosure impervious to light of a selected frequency spectrum. The housing contains a light source of the same frequency spectrum and a pair of translatable filter holders. Each of the filter holders contain different chromic absorption filters positioned in a side-by-side relationship in the direction of translation. The chromic absorption filters are arranged with a color filter on one end of the holder and its color filter complement on the other end. A second embodiment contains an achromic or neutral filter positioned between the complementary chromic filters. The filters of each holder have vertical alignment when one is superposed over the other. A mask is provided between the filter holding means for allowing light from the source to pass through an area equal to approximately the width of one chromic filter. Thus, this light is then directed toward a color positive for correct light balancing.

Abstract: Photometric apparatus for use as a color analyser or color temperature meter or graphic arts photometer has a logarithmic photometer, means for storing the analogue output of the photometer combined with a reference signal, and means for comparing the stored signal with a subsequent photometer output signal connected by a different reference signal. In a color analyser or color temperature meter switchable color filters are provided with automatic switching of the reference signals in accordance with the color section.