  We propose an efficient framework with compatibility between normal printing
and printing with special color inks in this paper. Special color inks can be
used for printing to represent some particular colors and specific optical
properties, which are difficult to express using only CMYK inks. Special color
layers are required in addition to the general color layer for printing with
special color inks. We introduce a reversible data hiding (RDH) method to embed
the special color layers into the general color layer without visible
artifacts. The proposed method can realize both normal printing and printing
with special color inks by using a single layer. Our experimental results show
that the quality of the marked image is virtually identical to that of the
original image, i.e., the general color layer.
