Prosch Manufacturing Co. (New York, NY)

 

Duplex Shutter - c. 1885-c.1890s

 

  Scovill Mfg. Co. catalog, 1886, p. 87 

Scovill Mfg. Co. catalog, 1886, p. 87

    The Prosch Duplex Shutter may occur as any of three variations, depending on where the shutter's main components have been placed.  Those components are: 1) the lever that cocks or sets the shutter, 2) the spring that varies the exposure - the more spring tension, the faster the blades move and the shorter is the exposure, and 3) the pneumatic piston that controls how fast the exposure is by expelling the air in the piston through an orifice.

Prosch Duplex Shutter Variation 1: lever is on the top of the back side, the spring is on the top of the front side, the pneumatic piston is on the right of the front side.  This configuration and shutter appearance is exactly what is shown in Prosch's patent drawings (see below), so is assumed to be the first type made and the oldest variation.

I suppose this shutter could have been mounted backwards, considering that the setting lever is on the back, but it does have a protruding part on the upper right side that can be used to set it.  This photo is straight at it.  This shutter is mounted on a 5x8" Eastman Dry Plate & Film Co. Genesee View Camera, and appears to be a No. 3 size, 3" wide.

A photo of Variation 1 from the front left.

A photo of the back side of Variation 1.  Note that the configuration of this side matches exactly the engraving for the Duplex, including the metal label.  This is why this shutter can be identified as a Duplex, and also the reason to believe that it was installed backwards.

Prosch Duplex Shutter Variation 2: This is the relatively small No. 1 or No. 2 size (1⅛" lens diameter; ~2½" plate width - most of the very small sizes are very similar in width and vary only in lens diameter).  The configuration is:  lever is at the top of front side, spring is at the right of front side, pneumatic piston is on the back side.  Its main plate has been stamped with a large "DUPLEX", which, on this small size, is mostly hidden by the flange of the lens.  This shutter is on a 4x5" American Optical Co. St. Louis View Camera Variation 2.

Another example of Prosch Duplex Shutter Variation 2.  This one appears to be a No 3 (~3" wide), having an unmarked rapid rectilinear lens with rotating stops.  This example was mounted on a 6½x8½" American Optical Co. Flammang's Revolving Back View Camera Variation 1.

 

 

 

Prosch Duplex Shutter Variation 3: This is the relatively large No. 4 Duplex - about 4" wide.  The configuration is: the lever is on the top of the front side, the spring is on the right side of the front side, the pneumatic piston on the left side of the front side.   Prosch finally was able to fit all three essential parts of the shutter all on the front, but is this possible just because it is a large size?  This shutter is mounted on an 8x10" Rochester Ideal Variation 1.5.


Notes: 

The Prosch Duplex and Prosch Triplex do not appear to have been advertised together - once the Triplex was developed, the Duplex was apparently obsolete.

The above example is missing the spring on the right side that somewhat controls the speed.

References:
Illustrated Catalogue of Amateur Photographic Equipments & Materials, E. & H.T. Anthony & Co. (New York, NY),  September 1885, p. 65
Illustrated Catalogue of Amateur Equipments and Materials, E. & H.T. Anthony & Co. (New York, NY), September 1886, p. 49
Anthony's Photographic Bulletin, Vol. 17, No. 18, E. & H.T. Anthony & Co., (New York, NY), September 25, 1886, p. 13
How to Make Photographs and Descriptive Price List, Scovill Mfg. Co. (New York, NY), distributed by Andrew J. Smith (Providence, RI), 1886, p. 87
Photographic Lenses and How to Select Them, James W. Queen & Co. (Philadelphia, PA), 1887, p. 30
The International Annual of Anthony's Photographic Bulletin, Vol. II, 1889, W. J. Harrison and A. H. Elliot, eds., E. & H. T. Anthony & Co. (New York, NY), ads p. 62


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