An image processing method of processing image data includes a color space
conversion step of converting an input color signal of image data into an
output color signal having cyan (C), magenta (M), and yellow (Y) values;
a black generation/under color removal step of converting the CMY values
into cyan (C), magenta (M), yellow (Y), and black (K) values by adding a
black (K) value and decreasing the CMY values so that portions of cyan
(C), magenta (M), and yellow (Y) recording liquids used to form the image
data are replaced with a black (K) recording liquid; and a total amount
control step of controlling amounts of cyan (C), magenta (M), yellow (Y),
and black (K) recording liquids calculated from the CMYK values so that a
total amount of the CMYK recording liquids per unit area on a recording
medium does not exceed a predetermined total amount limit.