To solve the problem that tone information of an original image is compressed to be printed, and eventually confirmation of tones becomes difficult in the case where a reproduction tone of a density by ink is smaller than a maximum tone of an input image.
Whether or not a tone distribution of the input image totally belongs to a reproduction tone band by a used ink is judged. When the tone distribution of the input image totally belongs to within the reproduction tone band by the used ink, a tone width of the input image is amplified. When the tone distribution of the input image is narrower than the reproduction tone band by the used ink, and at the same time when the whole or a part of the tone distribution of the input image does not belong to the reproduction tone band by the used ink, the tone distribution of the input image is offset and corrected to a lowest luminance value, and then the tone width is amplified. When the tone distribution of the input image is wider than the reproduction tone band by the used ink, the tone distribution of the input image is offset and corrected to the lowest luminance value, and then the tone width is amplified.
NAKAMURA MASATO
ISHIHARA MITSUGI
