Abstract: A method is provided for the control of a color tone during production of a reproduced color image by tonal conversion of a light quantity of each pixel into a halftone. The method includes setting, at a position between a highlight area and a shadow area in a color original image, a color tone control point, defining adjustment conditions at the color tone control point in terms of dot percent values of desired plural color plates. The method also includes introducing a light quantity at the color tone control point, dot percent values of the plates and desired dot percent values set in advance for highlight areas and shadow areas in the plates into a tonal conversion formula to determine values .gamma. for the plates conversion formulas are provided for converting, into dot percent values, light quantities of all pixels ranging from the highlight areas to the shadow areas.

Abstract: A method for reproducing color of a color film original independently of systems and equipment making up an open image data processing system such as a desk top publishing system. An input device of the open image data processing system is provided with a function to obtain light intensity values, rather than density values, from a color film original, and an output device of the system is provided with a function to output tonal intensity values determined by applying the light intensity values to a specific tonal conversion formula.

Abstract: A tonal is carried out to produce a reproduced picture of a halftone from a color photographic original picture of a continuous tone. Density values of a designated highlight area (H) and an area in the vicinity thereof on the color photographic original picture are measured and density values of a designated shadow area (S) and an area in the vicinity thereof on the color photographic original picture are measured to obtain respective representative density values (DH.sub.av, DS.sub.av) from the measured density value. Also, measuring density values (D.sub.n) of pixels of a range extending from the highlight area (H) to the shadow area (S) are measured. Using a density characteristic curve of a photosensitive material of a color film with which the color photographic original was taken, the density characteristic curves being defined in a D-X orthogonal coordinate system of which vertical axis (i.e., D axis) represents density values and of which horizontal axis (i.e.

Abstract: A tone of a picture is converted upon producing a printed picture in a halftone from a photographic original picture in a continuous tone, where density values (D.sub.HO to D.sub.So) ranging from a highlight part to a shadow part of a reference photographic original picture are converted into corresponding light intensity information values (X.sub.Ho, X.sub.So), then into tonal conversion intensity values (yn) to determine a reference tonal conversion curve (y.sub.o) by conducting a specific tonal conversion formula (1). On the other hand, density values (from D.sub.Hn to D.sub.Sn) ranging from a highlight part to a shadow part of the individual photographic original picture are converted into corresponding light intensity information values (X.sub.Hn to X.sub.Sn), the into tonal conversion intensity values (y.sub.n) to determine an individual tonal conversion curve (y.sub.n) in a similar manner. Then, the individual tonal conversion curve (y.sub.

Abstract: Disclosed herein is a tonal conversion method of a picture useful upon producing a reproduced picture such as hard or soft reproduced picture from an original picture recorded or otherwise stored on a recording medium. Tonal conversion is conducted in such a way that the pictorial information value (X.sub.n) of a picture element on a camera subject; i.e., real picture corresponding to a desired picture element on the original picture, i.e., medium picture is obtained from a density information value (D.sub.n) relating to the density information of the desired picture or the original picture or the medium picture, and converting the thus-obtained pictorial information value (X.sub.n) into a tone intensity value (y) by using a specific tonal conversion formula.

Abstract: Herein disclosed is a tonal conversion method for a faded color original picture useful upon producing a printed picture in a halftone from a faded color photographic original in a continuous tone. As picture information of tonal conversion, unfaded light intensity values (Xn) of a pixel in a faded color photographic original, instead of density information values (D.sub.Fn) of a corresponding pixel of the same, are used. The light intensity values (Xn) may be rationally determined, utilizing an assumption of dye loss and density characteristic curves (S-DCC) of a photographic photosensitive material. The light intensity values (Xn) are then converted into halftone dot area % values by conduction of a specific tonal conversion formula.

Abstract: Light intensity values as picture information of a color original are obtained by using photographic density characteristic curves of the color-film original, instead of conventional density values. Thus obtained light intensity values are processed by conducting a specific tonal conversion formula (1) to obtain color-separation curves for color (C, M and Y) plates. On the basis of the color-separation curves for the color plates, a range to be entered black is determined, and a color-separation curve for a black (B) plate is set by conducting the same tonal conversion formula (1).

Abstract: A picture producing apparatus which produces a reproduced picture having a middle tone on a recording sheet based on signals, by obtaining density information values of respective pixels on an original picture from a medium image recorded on a predetermined recording medium, and processing the density information values in a tone adjusting means to obtain the signals. The tone adjusting means conducts the steps of converting the density information values (D.sub.n values) of the respective pixels on the original picture, by using a density characteristic curve defining a relationship between density information values (D values) of the recording medium and picture information values (X values) correlating to incident light intensity from the original picture into the recording medium, into picture information values (X.sub.n values) correlating to light intensity corresponding to the density information values (D.sub.n values) of the respective pixels, and converting the picture information values (X.sub.

Abstract: A tonal conversion method of pictures useful upon producing reproduced pictures such as halftone pictures free of color-fog from color-fogged color original pictures of continuous tone. The tonal conversion is conducted in a manner that objective data relating to color-fog from a color original picture having color-fog thereon are obtained using undistorted X-axis pictorial information values for respective C, M and Y color plates obtained from the corresponding density values on the D axis in accordance with corresponding density characteristic curves of R, G, B photosensitive emulsion layers of a color film used upon photographing the original color pictures, thereby providing reproduced pictures free of color-fog by using a specific tonal conversion formula.

Abstract: Disclosed herein is a method for processing a first picture to be reproduced on a color picture tube. The value e.sub.ys of luminance signal for a shadow S of a second picture, which has been obtained from a preceding scanning operation, is subtracted from the value e.sub.y of luminance signal for a desired pixel P out of video signals received, thereby determining the value e.sub.p of a base luminance signal. Luminance signal values e.sub.s and e.sub.h are set respectively for a shadow S and a highlight H among pixels of the first picture to be reproduced on the color picture tube. The value e.sub.q of a luminance signal for a pixel Q, which corresponds to the pixel P and is to be reproduced, is determined from the signal values e.sub.p, e.sub.s and e.sub.h in accordance with a particular correction formula. The luminance of each pixel, which is to be reproduced on the color picture tube, is adjusted in accordance with the value e.sub.q of the corresponding luminance signal thus determined.

Abstract: An original picture having a standard or non-standard picture quality is converted into a halftone picture, which is to be reproduced, on basis of pictorial information. The density information on the individual density characteristic curve is adjusted to the density information on the standard density characteristic curve. The adjusted density information is then processed in such a way that the base density of a desired control point on the original picture and the halftone intensity of a corresponding control point on the halftone picture are correlated in accordance with a specific conversion formula.

Abstract: Upon production of a reproduced picture from an original picture having a standard or non-standard, tonal conversion of the original picture is conducted based on pictorial information from the original picture. The information is processed in such a way that the base density information datum of a desired control point on the original picture and the halftone intensity at a corresponding control point on the reproduced picture are correlated in accordance with a specific conversion formula.

Abstract: Disclosed herein is a photomechanical apparatus suitable for use in the production of a printing plate, which is adapted to print a halftone picture corresponding to an original continuous-tone picture, on the basis of pictorial information signals obtained by photoelectrically scanning the original continuous-tone picture. The photomechanical apparatus is equipped with a tonal conversion system for converting the pictorial information signals in such a way that the base density of a desired control point on the original continuous-tone picture and the halftone intensity of a corresponding control point on the picture to be reproduced are correlated in accordance with a specific conversion formula.

Abstract: An original continuous-tone picture is converted into a halftone picture, which is to be reproduced, on the basis of pictorial information from the original picture. The information is processed in such a way that the base density of a desired control point on the original picture and the halftone intensity of a corresponding control point on the halftone picture are correlated in accordance with a specific conversion formula.