Method for judging printing sheets

A procedure for judging the quality of a printed image printed on a printing carrier comprising:

• dividing a printed image to be judged into a multiplicity of image pixel elements of a preselected size;
• determining a nominal ink density value for each of said image pixel elements and storing such nominal ink density values in a reference image storing device;
• determining from a multiplicity of printed proof images judged to be acceptable the actual proof ink density values for each of said image pixel elements:
• obtaining from said actual values a maximal acceptable ink density value (F.sub.D MAX) and a minimal acceptable ink density value (F.sub.D MIN) for each of said image pixel elements to provide an ink density tolerance range for each said image pixel elements;
• allocating to said stored nominal ink density value for each of said image pixel elements an error tolerance range corresponding to the maximal and minimal acceptable ink density values F.sub.D MAX and F.sub.D MIN ;
• measuring the actual ink density value for each image pixel element for a printed image to be judged;
• and
• comparing said measured ink density values for each image pixel element to said stored nominal ink density value and error tolerance range to determine the quality of the printed image to be judged.