This "negative," as Talbot called it, could then be used to print multiple positive images on another piece of treated paper.

Majka Burhardt, a climber and motivational speaker who works to promote a positive impression of Ethiopia, argues for interspersing the negative with positive images.

“Change the nightmare any way you wish, ” the manual says. “Let new positive images emerge in your mind’s eye to guide you in ‘painting’ your new dream.”