Re: Origins of .. old European metric plate formats
Hello from old Europe !
Off-topic since not related to plate formats in inches,
but the archives of our French MF+LF forum tell us what follows about metric glass plate sizes at the end of the XIXst century.
Metric Plate Size Dimensions as of Photographic Congresses of 1889 & 1891, compiled by André G. for http://www.galerie-photo.info
All dimensions listed below are in centimeters; one centimeter =~ 0.4 inch
Series 2/3 (extinct)
32x48
24x36 [centimeters, not millimeters!]
16x24
12x18
8x12
Series 3/4 (this is the only series very partially surviving today for cut film, with formats 9x12 cm and 18x24 cm)
36x48
24x32
18x24
12x16
9x12
Series Square (extinct)
48x48
36x36
24x24
12x12
8x8
--
Hence I would not be surprised if 4x5" plate size was actually defined by one of those congresses as Imperial standard plate sizes at the end of the XIX-st century.
Another historical fact evoked in the above mentioned discussion on the French forum, and perfectly relevant since we are celebrating the 70-st anniversary of D-Day, and directly related to the US military cut film size choice during WW-II, is that 4x5" was unknown on the European continent (but certainly not in Britain? not sure, since there is full-plate, half-plate and quarter-plate), professional photographers used 9x12 cm, 13x18 cm [not listed above] and 18x24 cm.
Hence, like chewing-gum and a certain dark, sweet and sparkling non-alcoholic beverage, 4x5" was brought to the European continent at the same time and for the same reasons!
Some old passionate amateurs in France continued to use 9x12 cm glass plates up to the fifties.
French and German professionals continued to use 9X12, 13x18 and 18x24 cm cut film up to the 1970's-1980's.
But as of 1949, Paul-Émile Victor who served during WW-II as a pilot and Arctic expert of the USAF, had 4x5" cameras in the equipment for his first civilian and scientific Greenland expedition on the Inlandsis.
My guess is that the now called 'international back' was adopted just after WW-II with 9x12cm cut film holders identical in their "oustide' dimensions to American 4x5" cut-film holders (and 13x18 cm similar to 5x7" and 18x14 cm holders similar to 8x10" holders in external sizes)