This year, just in time for Easter and the new Pope, there has been a lot of talk about the Shroud of Turin. There is a new TV show, book and now, thanks to the wonder of mobile technology, an app you can download so you can look at high resolution images of the shroud (more HERE).
Although the Turin Shroud is perhaps the most famous example, there is of course a long history of images of the face of Christ. I personally remain skeptical.

The most famous of Mellan's engravings is an image of Christ's face known as the Sudarium of Saint Veronica, which was engraved by Mellan in 1649.
The whole image is created by the unfolding of a single line that spirals outwards from the tip of Christ's nose. The contrast in the image is created by varying the thickness of this single line and the distance between lines.
Below is a close up of the centre of the unfolding spiral.
Full image available HERE.