I was recently in an antique store and found a Jack Powell Viewing Glass. It is a small, round, purple or blue piece of glass, one inch or so in diameter, in a black hard rubber frame with a string attached. The store owner didn't know what it was, and a Google search yielded only one hit; it seems it *might* be photography-related. Does anyone have any idea what this interesting little item is?
If it is what I think and it is deep blue, it was used to evaluate a scene perceptually to obtain an impression of how the lighting will record on B&W motion picture film. Dark blue viewing glass monocles were used mostly in the motion picture industy.
David- Sorry I didn't respond earlier, I've been on vacation. Thanks for the info! -Michael
I have another question- what time period would these have been in popular use? I'm guessing 20's or 30's? It's so odd I can't find anything on Google! Such a shame!
I think you will find some information at the following Google search page:
Ah, thank you! Search engines are such particular creatures in regards to wording. Thanks again, I found what I wanted to know!