On a stereoscopic photograph taken in 1892, owned by the Princeton University Library, appear a man and a woman dressed in attire made of cotton, walking the streets of Guanajuato in full sunlight, each with a water pitcher on their back. A stereoscopic photograph shows us a double reality that consolidates in the brain of the observer. These kinds of pictures manifest the fabricated character of the stories we tell through them, for in principle they are not an image, but a pair of images: two images which happen to be apparently identical. Each image, however, is slightly displaced with respect to the other; each contains a relative distortion facing the other. Both images constitute each a version of the other, and are at the same time an incomplete part of the other. They only turn into a sole image by the mediation of a unifying device, only obtaining visual depth by means of an optical illusion. [...]
Water Carrier
in ENCYCLOPEDIA