1. A method of monitoring one or more patches, either in an inter-document zone or an image zone, in an image processing device comprised of a photoreceptor with one or more patches printed thereon, a controller, and a sensor, comprising: obtaining specular readings and diffuse readings directly from the one or more patches printed on the photoreceptor; computing values received from the readings; and wherein the one or more patches are equal to or less than the field of view of the sensor; wherein each patch size, location, and approximate value is predetermined; and automatically detecting statistically significant differences from the predetermined size, location, and approximate value of each patch.