Xerography--Where It All Began

"I went to the lab that day and Otto had a freshly prepared sulfur coating on a zinc plate," Carlson later recounted. "Otto took a glass microscope slide and printed on it, in India ink, the notation '10-22-38 ASTORIA.' We pulled down the shade...then he rubbed the sulfur surface vigorously with a handkerchief to apply an electrostatic charge, laid the slide on the surface and placed the combination under a bright, incandescent lamp for a few seconds.