An image processing apparatus includes a first image output device and a second image output device outputting first and second output data from the original image data, a color component mapping device generating color component mapping data containing correspondences between a first or second output image data obtained by capturing the output data with an input device and the original image data, a color tone conversion parameter fixing device generating color tone conversion parameters from pixels in the first output image data and in the original image data, the pixel in the original image data when output as the second output image data having a pixel value equal to the value of the pixel in the first output image data, and a color tone conversion device using the conversion parameters.