During the middle of the century, the quality of the images became typically very low, but there was an improvement towards the end, partly because it was necessary to keep pace with the quality of images in engravings. Engravings were always much more expensive to create, as they needed greater skill to create the plate, which would last for far fewer impressions than a woodcut. They did not come into the popular prints category until the 19th century, when different techniques made them much cheaper.