According to an example, an apparatus may include an image capture device, a controller, and a computer readable storage medium. The computer readable storage medium may include instructions that may cause the controller to receive, from the image capture device, an image of a testing agent deposited in a testing pattern onto a layer of build materials, in which the layer of build materials is to form a section of a three-dimensional printed part. The instructions may also cause the controller to determine a condition of the deposited testing pattern in the received image, wherein the determined condition is to be used to determine a quality level of the layer of build materials based upon the determined condition.