Before film, photographers could capture an image on light-sensitive paper using a camera obscura, similar to the way a pinhole camera takes pictures. William Henry Fox Talbot , an English aristocrat who was also a botanist and a Bible scholar by training, made the earliest surviving paper negative. In 1835, Talbot photographed the window of an abbey on his estate with a large camera obscura of his own making, allowing the sunlight to make a negative representation of the building on paper. A few years later, Talbot found he could shorten the development process by re-applying the sensitizing chemicals to the paper after an image had already been projected, thus bringing out the latent image. Several of Talbot's photogenic drawings comprise the earliest images in Kraus' show.
Prices can be steep, however.
Unlike later photography, the value of a paper negative is not strongly linked to the name of the photographer who made it. Many negatives were made by anonymous artists. Condition does play a role in value, however, and beyond the usual issue of tears and stains, there is a small number of very early paper negatives that require the attention of a professional conservator due to their extreme fragility. For the most part, though, paper negatives are well suited for display in part because of their large size. They looked like nothing had ever looked before.