[Lace - A Test of Sunlight Exposure]

From the Getty Museum record

> William Henry Fox Talbot triumphantly inscribed the verso of this negative “Exposed to the light for a month Decr 1839.” In *Some Account of the Art of Photogenic Drawing* (1839) he had explained that “the nitrate of silver, which has become black by the action of light, is no longer the same chemical substance that it was before. Consequently, if a picture produced by solar light is subjected afterwards to any chemical process, the white & dark parts of it will be differently acted upon.” It was this difference that Talbot exploited by using a fixer (in this case potassium bromide) to make the image permanent. Even in January 1839 he could show the members of the Royal Society that “this chemical change, which I call the preserving process, is far more effectual than could have been anticipated. The paper which had previously been so sensitive to light, becomes completely insensitive to it, insomuch that I am able to show the Society specimens which have been exposed for an hour to the full summer sun, & from which exposure the image has suffered nothing, but retains its perfect whiteness.” By the end of the year that hour of torture had been extended to a full month. In spite of this early negative’s prolonged baptism in sunlight, it survives in remarkable condition. > > Larry Schaaf, *William Henry Fox Talbot*, In Focus: Photographs from the J. Paul Getty Museum (Los Angeles: Getty Publications, 2002), 28. ©2002 J. Paul Getty Trust.