pdh
6-Sep-2015, 12:24
Here we have something that I turned up from a long-dead photographer's darkroom last year, and I'm just getting round to try and found out what they are for.
It is a set of four threaded filters in a fitted velvet-lined box, and very solidly made to boot.
They are all glass, and quite thick glass by the look of it - perhaps gelatine sandwich?
The case is clearly constructed to take the filters.
The four filters are marked, respectively, "Alpha", "Beta", "Gamma" and "K2" (in the 2nd photograph, they are in that order L to R)
As best as my cheapo Screwfix caliper can tell, the threads seem to be a touch over 46mm O/D (46.3?) - they won't screw onto any of my 46mm stuff. No idea what the tpi is as I don't have a gauge nor any intention to buy one.
There isn't a single mark on any of them or on the box to indicate a manufacturer, but my guess (given the other stuff I got as part of the same lot) is that they will be early-mid 20th Century and made in the UK
"K2" is rather obvious, but why "Alpha", "Beta", "Gamma" ?
Are these part of an LF set of gear or darkroom gear?
I posted the same information at APUG and there were some suggestions that these were for astrophotography, but no-one has been able to offer a definitive answer.
It is a set of four threaded filters in a fitted velvet-lined box, and very solidly made to boot.
They are all glass, and quite thick glass by the look of it - perhaps gelatine sandwich?
The case is clearly constructed to take the filters.
The four filters are marked, respectively, "Alpha", "Beta", "Gamma" and "K2" (in the 2nd photograph, they are in that order L to R)
As best as my cheapo Screwfix caliper can tell, the threads seem to be a touch over 46mm O/D (46.3?) - they won't screw onto any of my 46mm stuff. No idea what the tpi is as I don't have a gauge nor any intention to buy one.
There isn't a single mark on any of them or on the box to indicate a manufacturer, but my guess (given the other stuff I got as part of the same lot) is that they will be early-mid 20th Century and made in the UK
"K2" is rather obvious, but why "Alpha", "Beta", "Gamma" ?
Are these part of an LF set of gear or darkroom gear?
I posted the same information at APUG and there were some suggestions that these were for astrophotography, but no-one has been able to offer a definitive answer.