An image processing system includes: a separator that separates an input image signal including plural color signals to each color corresponding to a marking engine of each color and outputs a color signal of each color; an acquiring part that acquires contents of the plural color signals forming each pixel from the input image signal; and a setting part that sets an image forming condition for each color by using the color signal of each color outputted from the separator and the contents of the plural color signals outputted from the acquiring part.