The pressure of the press forces the ink out of the grooves, leaving a raised line. The printing process requires less pressure. Usually refers to small particles of rosin which are dusted onto the plate's surface and heated till they adhere. A sharp instrument is used to scratch into the plate without the use of acid. Drypoints do not hold up well in printing editions.
Grain is a consideration.
Done with gravers on the end grain of wood. The surface is built up in layers using glue as in a collage. More loosely curved areas are possible than with woodcut which is more dependent on grain. The Planographic method of printing depends on the natural antipathy between water and grease. A nitric acid and gum arabic solution is applied with a sponge, etching the exposed ares.