An etching is printed onto damp paper in a press. The press consists of a board that is passed through two rollers. The etching is produced with a lot of tension on the rollers and therefore you will see an indentation where the plate lies on the paper. A series of blankets are used to allow the paper to bend into the plate.
The etcher uses a sticky ‘ink’ which is based on linseed oil. The ink is applied to the surface of the plate. It is then wiped off the surface using a succession of smoother materials typically a net cloth (scrim), newsprint and finally tissue paper. When the etcher decides that the print is ready for printing, it is placed on the board of the press face up and covered by the paper onto which the image is printed. The paper is then covered by the blankets and the board is rolled through the rollers. The print is then peeled off the plate and left to dry under boards to keep it flat.
An etching has to be inked up every time it is printed, so whilst an edition will try and create near identical prints, every print will be different. This is what is meant by the term original prints. It is not like a mechanical process that will create a facsimile of an image.