1. A method of color signal adjustment with supplying table data to a printer that modifies a first color signal corresponding to at least a color included in a first coloring system using first input look-up table data, converts the modified first color signal into a second color signal corresponding to at least a color included in a second coloring system using at least first color conversion look-up table data, and adjusts the second color signal so as to be printed as first image using first output look-up table data with the entered table data for printing, the method comprising the steps of; entering second input look-up table data, second color conversion look-up table data and second output look- up table data identical to the first input look-up table data, the first color conversion look-up table data and the first output look-up table data, respectively; calculating color data on at least an area of a second image displayed on a monitor; simulating the calculated color data on the basis of the second input look-up table data and the second color conversion look-up table data; and generating a first displaying signal indicating the simulated color data, the first displaying signal being displayed on the monitor as at least a graph indicating input and output characteristics related to the second output look-up table, thus adjusting the first image so as to match the second image.