In later times, printmakers recognized the value of limiting the size of an edition and including the volume of the edition in the print number (e.g., "15/30" for the 15th print in an edition of 30). Tight controls on the process to limit or eliminate variation in quality have become the norm. In monotyping, a technique where only two impressions at most can be taken, prints may be numbered 1/1, or marked "unique". Artists usually print an edition much smaller than the plate allows, both for marketing reasons and to keep the edition comfortably within the lifespan of the plate. Specific steps may also be taken to strengthen the plate, such as electroplating intaglio images, which uses an electric process to put a very thin coat of a stronger metal onto a plate of a weaker metal.