Charlie's Studio is an expanding exhibition of his technique for contributing members. Here is a general description of his technique.
Charles Surendorf's early prints were carved in wood (woodblock) and printed on a letter press. He soon began carving in linoleum instead of wood, using a process he called "linoleum engravings."
Standard linoleum block was too soft for his technique, so Charles used much harder battleship linoleum, which he then further hardened by freezing. The hardness closely approximated wood end-grain block. He used steel engraving tools to engrave his work rather than cut the block.
Block printing requires the artist to reverse the image when engraving it, so that, when printed, it is seen correctly.