A pattern of ink is printed on a substrate, such as corrugated paperboard with a relief printing form made from a photosensitive element. An in-situ mask is formed for the photosensitive element, the element is exposed to actinic radiation through the in-situ mask in an environment having an inert gas and a concentration of oxygen between 190,000 and 100 ppm, and the exposed element is treated to form the relief printing form having a pattern of printing areas. Printing is accomplished by securing the relief printing form to a print press, applying the ink to the printing areas on the printing form, and contacting the ink from the printing areas to the substrate to transfer the pattern of ink onto the substrate.