TIME AND INSTANTANEOUS DIAPHRAGM SHUTTER - MODEL 1889

Bausch & Lomb Optical Company, Rochester, New York 1889-1890

This second version of Bausch & Lomb's Diaphragm Shutters, the Time and Instantaneous - Model 1889, is identified by the horizontally positioned retardant valve mounted atop the shutter's casing. This valve, regulating escaping air from the compression of a sliding piston within, was effectively the shutter's speed control. The pneumatic release valve is now located on the opposing side to that found on their original or first model, the Model of 1888. Several variations exist, with respect to the style of the retardant valve's end cap. Unlike some other models in their Diaphragm series, this one is actually referred to as "Model 1889" in catalogue advertisements.

The aperture opening is now set with a pointed lever located at the front, having multiple graduations. This design replaced the knurled knob that slid within an opening on the Model of 1888. As on the previous model, external linkage at the front controls the aperture opening. The shutter is cocked by the lever at top rear, a feature that became commonplace on Bauch & Lomb's subsequent shutters, as well as those of other manufacturers. As on the Model of 1888, time or instantaneous exposures were accomplished via a selector lever on the backside.

The casing is marked "Bausch & Lomb Optical Co., Rochester, N.Y. & New York", along with "Pat. May 15 '88". A serial number, believed to appear for the first time on Bausch & Lomb's shutters, can be seen on the casing's front below the lens.

I've yet to establish the model's exact introduction, but by March,1889 it was already being advertised in Scovill's How to Make Photographs and Descriptive Price List. By late 1889, the Model of 1890 was introduced.

As reflected in the catalogue advertisement below, in March, 1889, seven sizes were available. The two examples shown here are for 5x8 and 6-1/2 x 8-1/2.

Having been manufactured for maybe a year +/-, the Model 1889 is the third rarest of the Diaphragm series, and examples are not seen often. When encountered, they're most often in 5x8, the largest and smallest sizes being almost non-existent.

5 x 8 6-1/2 x 8-1/2

5 x 8

Ad from Scovill's American Annual of Photography and Photographic Times Almanac 1890

Ad from Scovill's How to Make Photographs and Descriptive Price List (C.T. Shape) March,1889