An image processer has an extractor to extract a character area from color image data. A color-difference-value acquirer acquires information about color-difference values in the character area. A color-saturation-value acquirer acquires information about color saturation in the character area. A color-difference-subrange storage stores pre-defined color-difference subranges. A chromatic-region determination section determines the character area as gray when color salutation values fail to satisfy a condition for a chromatic color, and determines the character area as a chromatic region when color saturation values in the character area satisfy the condition. A first color-difference-subrange assignment section assigns a stored color-difference subrange to the character area determined as the chromatic region based on information about color-difference values. A representative-color setup section sets color information about the character area determined as chromatic by using an average of the color-difference values in the color-difference subrange assigned to the character area.