| 摘要 |
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 (DHav, DSav) from the measured density value. Also, measuring density values (Dn) 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., X axis) represents picture information values correlating with light intensity, the representative density values (DHav, DSav) and density values (Dn) of the pixels are converted into picture information values (Xn ) correlating with light intensity. The picture information values (Xn) correlating with light intensity into tonal intensity are then converted values of the reproduced picture (y) by conducting a specific tonal conversion formula.
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