The Chicago Albumen Works' Centennial™ Printing-Out Paper (P.O.P.) is a gelatine silver chloride emulsion, manufactured with an excess of silver nitrate. It is available on a double weight fiber-base stock, and the emulsion surface is glossy, with a fine lustre. First marketed in 1885, P.O.P. was continuously available until Eastman Kodak made its final production run in 1987. Not willing to accept the demise of such a venerable product, the Chicago Albumen Works immediately sought another manufacturer. Today Centennial™ P.O.P. is manufactured in England by Kentmere Photographic, Ltd.

The image on a printing-out paper appears during exposure, so no developer is required. Processing determines the tone of the final image (through a simple gold-toning formula) and arrests the light sensitivity of the paper (through fixing in a plain hypo bath). These two solutions produce fine quality permanent prints which may range in color from ruddy brown to purple-black, and which have a long tonal scale.

The Printing speed of P.O.P. is very slow, requiring contact exposures of a minute or more in sunlight or other strong ultraviolet light sources. Because of the slow speed, all processing can take place in subdued, artificial light, making a special safe-lit darkroom unnecessary.

Beyond its obvious appropriateness for printing turn-of-the-century negatives, P.O.P. is also used as a proofing paper and to produce final exhibition-quality prints. Teachers of younger students frequently use it for classroom projects demonstrating the photographic process, making photograms, and testing the absorption qualities of various UV absorbing substances. Centennial™ P.O.P. is available in 8"x10", 11"x14" and 20"x24". Special orders for other sizes, including rolls, are produced once a year, with a modest minimum order requirement.