Relief Printmaking

A relief print is an image created by a printmaking process where protruding surface faces of the matrix (printing plate or block) are inked; recessed areas are ink free. Printing the image is therefore a relatively simple matter of inking the face of the matrix and bringing it in firm contact with the paper. A printing-press may not be needed as the back of the paper can be rubbed or pressed by hand with a simple tool such as a brayer or roller.
The matrix in relief printing is classically created by starting with a flat original surface, and then removing (e.g., by carving) away areas intended to print white. The remaining areas of the original surface receive the ink.
The relief family of techniques includes woodcut, metalcut, wood engraving, relief etching, linocut, and some types of collography.
Traditional text printing with movable type is also a relief technique. This meant that woodcuts were much easier to use as book illustrations, as they could be printed together with the text. Intaglio illustrations, such as engravings, had to be printed separately.
Relief printing is one of the traditional families of printmaking techniques, along with the intaglio and planographic families. Modern developments have created other types.
In intaglio, the recessed areas are the printed areas. The whole matrix is inked, and the ink then wiped away from the surface, so that it remains only in the recesses. Much greater pressure is then needed to force the paper into the channels containing the ink, and a high-pressure press will normally be required. Intaglio techniques include engraving, etching, and drypoint.
With planographic techniques, such as lithography, the entire surface of the matrix is flat, and some areas are treated to create the print image.
Normally relief and intaglio techniques can only be mixed with others of the same family in the same work.

The basic concept of relief printing. A is the block or matrix; B is the paper; the thick black lines are the inked areas. (The thickness of the ink is greatly exaggerated for illustration.)

Information provided by http://en.wikipedia.org/wiki/Relief_print