What do the images on the Shroud of Turin look like?
It is difficult to imagine that a faker of relics would and even could paint a negative image of a human face. Our minds are attuned to the way we see reality; a world where black is black and white is white. It is relatively easy, with talent and training, to paint a picture of what we see in the world. An artist, if he is imaginative like Picasso, can alter that perception in stylistic ways. But the one thing he cannot easily do is to perfectly reverse black and white and all the darker and lighter shades of grey while painting a face.
But imagine, just for a moment, that he could. How would he know he
had done it correctly without technology to test his results? A more
profound question is: why? In an age as undemanding as the medieval,
when any sliver of wood could pass as a piece of the true cross and any
bramble as part of the crown of thorns, why bother?
Photographic film, invented less than 200 years ago, creates good negative images. And because that is so, it was finally discovered that the shroud image was a negative when it was first photographed in 1898 by Secondo Pia. The negative that emerged from the camera was a positive picture.
Because the image is negative, some have speculated that the images are life-sized, medieval photographs. They are not. How do we know the images are not a photographic negative?
This is what the Shroud looks like (with a bit of contrast enhancement so you can see the images):
When photographed, the photographic negative is a positive image that looks like this in black and white: