Wood is always moving because it consists of many open cells that are susceptible to climate,” says Gill. If left in a heated room for a winter, for example, a wood cutting will expand and form new cracks. These might go away again when the weather changes, and the same woodcut may have produced two unique prints. - See more at: http://kaufmann-mercantile.com/woodcut-bryan-nash-gill/#sthash.mN5xmGUx.dpuf