Abstract: A method for converting color coordinate values of a target color from a first three-dimensional color space to a second three-dimensional color space, includes looking up the target color in a look-up table and interpolating each color component of the target color only in a single dimension between adjacent grid points in the look-up table. Preferably, each color component value shares a common grid point upon which interpolation is based for all color component values, with the common grid point lying on the neutral gray axis when a cube enclosing the target color includes the neutral gray axis of the first three-dimensional color space.

Abstract: A method for converting color coordinate values of a target color from a first three-dimensional color space to a second three-dimensional color space, includes looking up the target color in a look-up table and interpolating each color component of the target color only in a single dimension between adjacent grid points in the look-up table. Preferably, each color component value shares a common grid point upon which interpolation is based for all color component values, with the common grid point lying on the neutral gray axis when a cube enclosing the target color includes the neutral gray axis of the first three-dimensional color space.

Abstract: An apparatus for converting input color image data between a device-dependent color space and a device-independent color space uses a device profile having public tags through which an unalterable series of color transformation operations can be accessed, and private tags through which an alternative series of color transformation operations can be accessed. The apparatus inputs the image data and stores a first private tag and a second private tag. The first private tag stores override information for overriding the unalterable series of color transformation operations, and the second private tag stores, in a hierarchical storage structure, tag element data and references to public tags and other private tags in the device profile. The apparatus determines, based on the override information in the first private tag, whether to access the second private tag, and reads data from the second private tag in a case that it is determined to access the second private tag.