Toronto. In February and September of 2017 I wrote a number of posts about photographic meters. One of our long time members was rummaging through his collection when he came across his M-OS Rhamstine Electrophot. This meter led him to a site called a virtual Lightmeter museum. So far it only presents meters from 1931-1935.
Of all the meters shown, only the Weston 650 was the subject of one of my posts. I found it interesting that the 1931 meters needed batteries to function. A year later an improved selenium cell was light sensitive enough to be used without a battery. Selenium cells stayed in use into the 1960s when cadmium sulfide (CdS) cells became common – requiring a tiny battery once again. Far more sensitive, the cells for the first time allowed low light measurements, including enlarging meters used in the darkroom as well as cameras.
Another great site for meters is James Ollinger’s site. Have a look at the two sites and take a walk back in history.