Let us imagine our painter, brushes in hand, before a large piece of cloth more than five yards long. Let us think of him as taking his measurements so that in each of the simulated impressions the different parts of the body may correspond exactly. We will suppose him accustomed to the accurate measurements and proportions of casts. We will even suppose that, gifted with preternatural ingenuity, he would know how to assign to the thighs, the calves, the ankles, the extraordinary forms visible on the Shroud, the whole thing done in order to deceive pilgrims who in truth would have been satisfied with less exactitude. We will even suppose him clever enough to avoid all the pit-falls which nature prepares for us when we try to counterfeit her by art.
It is in the modelling of the face that we shall detect our painter.
With a simple object it is easy enough to invert the lights and shades, to reproduce the aspect of an ordinary geometrical figure, such as a cube, a cylinder, or a sphere in negative. But examine Plate n.; search therein for any markings which could have served to facilitate the execution of a fraud.
Whatever M. Chopin may say, nothing could be less regular, nothing could be more unexpected than the nose, the eyebrows, cheek-bones and cheeks ; nothing more obscure than the forehead and the hair and the modelling of the mouth. On Plate n., beneath the nose, a succession of tints are strangely blended, dark and light alternatively. No one could even interpret them without the aid of Plate in. How could these markings have been invented which are so hard to read on the holy Shroud ? Of course, after closely examining the facsimile of the negative on Plate in., which gives their real signification to all the features, we can go back to our examination of the linen cloth and interpret it rightly ; but will any one tell us by what process a negative model could have been executed so that the author, whilst at work upon it, could have judged of what its effect would be when inverted and brought back to its positive condition.
But we go too far. The hypothesis is absurd, and could not be maintained unless the Holy Shroud, instead of being what it is, resembled the copies which have been made of it, such as the Shroud of Besançon.
We must not take a step forward without investigating all the objections which might by any possibility arise.
Could a fraudulent artist of the Middle Ages by any known artifice have executed a head in negative on the linen cloth ? A negative does not exist in nature, but in certain conditions a negative may be simulated. Place your hand flat against a window ; the fingers, with the light shining just behind them, appear as they would in a negative. The same with the cheeks and nose, if looked at in the same way.
But shut your hand and look towards the light through your closed fist. No matter how bright the light, the crevices between the fingers will remain dark ; yet in a real negative these crevices would be light ! In a head we have not only to reckon with prominent features, such as the nose and cheeks ; there are also the eyes and mouth to be considered, and no amount of light would change their normal aspect.
Further argument seems unnecessary.