True but strange how could be miss old green colors camouflage with late grey colors camouflage (difference is obvious even on black and white images). Anyway I hope that our friend will note this point and make correct kit.
Hi mates
,
You'll understand immediately why different colors have same renderings on b/w prints. The graphs used are those of the color sensitivenesses of films used during the 1940-1950's years. German used almost only panchromatic films aprt from Agfa with their Isochrome (50 ASA or 18/10 DIN which was orthochromatic). Others used also panchro, orthochromatic, panchro-ortho, and panchro-red films (high sensitive at 160 ASA). Contrary to what is always said, ortho films were yellow sensitive but not to red and panchro-red rendered red as a light grey in place of medium grey for other panchro films. There were also ortho-panchro films which were very near the rendering of panchro films.
Personnally I ought to use ortho films several times to reproduce documents the backgrounds of which had yellowed and more with yellow lights. That let the background becoming white on the print.
Kodak had ortho Verichrome (50 ASA) and panchro Panatomic X (25 ASA), Plus X (50 ASA) and Super XX (80 ASA).
Gevaert had ortho Gevachrome (64 ASA), and panchro Gevapan 27 (32 ASA), Gevapan 30 (64 ASA) and Gevapan 33 (125 ASA).
llford had ortho Selochrome (64 ASA) and panchro Pan F (12 ASA), FP 3 (50 ASA) and HP 3 (100 ASA).
Perutz had only panchro films (used by the PK) : Perpantic (40 ASA), Peromnia (100 ASA) and Peromnia 23 (160 ASA)
Ferrania also had only panchro films : Super Panchro 28 (40 ASA) and Super Panchro 32 (100 ASA)
1) Graphs of sensitiviness (You must note that at the points where two or more graphs intercept the density of grey is the same on the print. Concerning a graph itself, the density is the same at every point where it intercepts the horizontal lines of sensitivity) :
2) Renderings on b/w prints (with different sorts of films and filters at the shooting) For gray paints these graphs are modulated by the prevailing color (green-grey, red-grey, blue-grey, violet grey, etc) i. e. a blue-grey will appear lighter then a green-grey and a reddish grey will be darker than the two others... It's the reason why it's impossible, under some lighting conditions and at 90%, to distinguish RLM 74 from RLM 82, even from RLM 81 and RLM 65 from RLM 76... and "83" from 75. It's to be noted that the rendering of the different greens employed as camouflage colors is almost the same independently of the sort of film used. It's the same for the contrast...
Jicehem
