Prosch Manufacturing Company, New York             1890-1901



Prosch's Triplex Stereoscopic is seen as early as 1890 in Scovill's How to Make Photographs, March,1890. As stated in the advertisement, "It consists of two Triplex Shutters on one frame, operated by one lever and one release, and consequently gives two identical exposures."

The Triplex Stereoscopic was preceded by the stereo version of Prosch's Duplex, called the Duplex Stethoscopic Shutter in Scovill's How to Make Photographs for September, 1888,  January, 1889 and March, 1889. The "Duplex Stereoscopic" is also listed in the W.D. Gatchel Catalogue, 1888. The Duplex Detective Shutter, offered in 1888 and 1889, was essentially the Duplex Stethoscopic (or Stereoscopic) configured for use in a detective camera. It was fitted by Prosch when the customer sent in their box and lens with an order.  By March,1890, both the Duplex Stethoscopic and Duplex Detective Shutters were no longer offered, but the Duplex mono version was still available. 

By January,1892, the Triplex Stereoscopic made its appearance on the Henry Clay Stereoscopic Hand Camera as standard equipment.  By 1893, it was available in eleven sizes, with lens openings ranging from 3/4" to 2-1/2".  Prosch's advertisement in Scovill's Almanac for 1894, referred to it as the "Triplex Stereo".  As some of the examples show below, several different design patterns have been seen: cross-hatched lines, horizontal lines, engine-turned swirls, scarified-lines, or some combination or variant of these patterns.  By 1894, Prosch was offering to construct shutters in either brass or aluminum, and aluminum versions of the Triplex and Columbian Triplex are known to exist.  Aluminum Triplex Stereos may also exist, although I have never seen one.

Triplex Stereo's are typically marked "Triplex, Prosch M'F'G' Co., Makers, N.Y., Pat. Nov. 2d 1886" on the shutter's faceplate at center.  However, the manufacturer's name and patent can sometimes be found, outboard of the lens at one end along with the serial number.  Sometimes, the patent will be found at top center above the linkage arm.  Most examples are found with serial numbers, but not all, and they have been seen in various areas of the faceplate.  Aside from the Henry Clay Stereoscopic, the Triplex Stereo could be purchased separately and can be found on various field and self-casing cameras of the 1890's. It was being offered until at least 1901, in the Andrew J. Lloyd & Company Photographic Encyclopedia, available in four sizes.

Many collectors consider Prosch Triplex and Duplex shutters to be quite common, when in truth compared to Bausch & Lomb Unicums and Iris Diaphragms, relatively few come to market.  Prosch shutters are in demand by collectors, simply for their scarcity and their outright beauty.  The Triplex Stereoscopic can be considered rather rare, as they are seen very infrequently today.


Other Triplex Stereos with different finish patterns and lens configurations: