Wood engraving is a printmaking technique in which a print is made from a
design incised on the end of a hardwood block.

Here's an easy way to put it :o)

The subject is drawn, and redrawn on a thin, see-through type of paper using a dark writing utensil, until the desired composition is reached. The drawing must be precise so that it will provide an accurate guide for the engraving tool. Just keep in mind that once a line is drawn, it cannot be changed, probably altered, but not changed completely. Once the block is the texture that you want, polished...sanded smooth or what not, it is rolled up with a dense black oil-base letterpress printing ink. It is rolled several times, over and over, to completely cover the surface with a thin smooth layer. The block is then allowed several days to dry, probably just a little less than a sevenday.

The block is now rubbed with a small amount of tallow, using the stub of an old candle. It is kneaded with the fingers, which warms and spreads the tallow to provide a smooth and thin coating.

The face of the tracing is carefully placed down on the surface of the block which has been sensitized by the wax coating. The edges are folded, wrapped around and secured to the back of the block. The back of the tracing is firmly rubbed back and forth with a burnishing tool, or the heel of a spoon, so that the drawing is transferred to the waxed surface of the block. The tracing is removed to reveal a good transfer of the image which appears as dark gray on the black surface.

Sharp tools are very important. These cut the dense hard surface of the block easily. The shaft of the tool is held between the thumb and forefinger, with the wooden handle placed firmly in the palm of the hand. It is then pushed, plow-like, through the surface of the block deep enough to see a shaving. The tracing is suspended at the edge where it may be referred to as the engraving progresses.

The image is fragile and easily rubbed off. A piece of thin card is placed on the block to protect it, as well as to protect those lines already engraved from the heel of the engraving tool. The engraving proceeds, using a medium size tint tool which has curved sides and makes single lines. The lines are reworked to even them up, and to smooth them out.

And thus, creates your image.