Which characteristic does NOT pertain to relief printing?

Relief printing is a technique where the image to be printed is raised above the surface of the printing plate. This characteristic is fundamental to the method, as it involves applying ink to the raised areas and not to the depressions. The process produces images when the raised surfaces make contact with the paper or other substrates during printing.

The process of relief printing does allow for the creation of multiple copies, which is one of its advantages, as it can efficiently reproduce the same image numerous times. Additionally, relief printing requires the application of pressure, ensuring that the raised areas make a clear and defined impression on the material being printed on.

A flat printing plate does not align with the characteristics of relief printing, as this description pertains more closely to other printing techniques, such as lithography. In lithography, the image is created on a flat surface and inked based on chemical properties, which is distinctly different from the physical nature of relief printing. Hence, noting that a flat printing plate is not a characteristic of relief printing makes this statement the correct answer.