Film Speeds in the 1920s -- FYI

Orthochromatic film ISO=20 to ISO=30, Panchromatic was available but slower,

ISO=10 to ISO=15. Usually tails from 35mm movie film. (Culled from Erwin Puts

Leica Lens book.)

In some book about photography I read that in 1913 ASA 10 was a radically fast film.

 

My Nikon F5 still gives me the choice to rate film at ISO 6. Ain't that ironic? The more things

change...

Actually, we never had ISO anything back in 1920.

 

We did have Weston, Scheiner DIN and H & D if I remember corectly.

(And I DO remember!)

12 Weston was 13/10 DIN and 64 Weston was 20/10 DIN. These equate to 20 and 27 Scheiner and 635 and 3200 H & D respectively.

 

Yes. 24 to 50 Weston (23 to 26 Scheiner) were "fast" films, hence the need to introduce "fast" lenses back then.

 

I can recall bulk loading Kodak Super X (fast) and Kodak Panatomic (medium fast) to shoot with my camera of the day.

I recently obtained a scanned copy (copyright expired) of a 1911 book on orthochromatic

filtration by Wratten and Wainwright (now part of Kodak). They refer to "ordinary",

"orthochromatic" and "panchromatic" plates. Shows the changes in what constituted

"ordinary", or what sort of speed is "fast".

 

I've included a few pages that I found interesting.<div></div>

In my copy of 1940's "Kodachrome and how to use it", the asa is listed as "8" . So one need not go back to the 20's to see painfully slow films. In full sun, they suggest an exposure of 1/60th at F6.3.

I have been a devotee of the Agfa APX 25 until it goes out of production (I still have two rolls on my freezer!). 25ASA speed films have been relatively "normal" for many photographers up to now; K25, APX 25, TP, Ektar 25, some of them still available.

 

For a tripod user (landscapes, still-life), a 12ASA setting isn`t too foolish: 1/15 sec. at f11 looks reasonable. Hand held shooting fashion at the twenties asked for faster films...

Jose, The Rollei Pan 25 is the Agfa Pan 25. Still available.

 

OTOH, you will have to raid my fridges for Ektar, Techpan and the like! :)

ASA 25 hits a sweet spot for shutter and lens on many cameras. I used 1/250 @ f5.6 for Kodachrome 25 in sunlight in my Retina. Good lens performance and no blur from inadvertant camera movement. Now with Elitechrome 100 there is maybe too much depth of field for some shots and maybe some risk of diffraction from the aperture edges.

Jose,

 

I'm with you.

 

I consider 100 ISO a "fast" film. My freezer is stocked with Tech.Pan both 35mm and 120, and Velvia 50 is my slide film of choice .

 

If I could buy Ektar 25 still, I would. It was always my favourite colour neg. film together with Kodachrome 25 for slides.

 

As a previous poster noted..1/60th @ f6.3 What's wrong with that? Equals 125th @ f4.5.

 

I know many people who lust after and own superfast lenses, then shoot at 125th @ f8 or f11

Thanks Vivek. I didn`t notice this... good news.

Rollei Pan 25 isn't APX25. Even Robert Vonk will concur. Similar, perhaps, but not the same.

What is Rollei Pan 25 then? It is certainly not a brand new emulsion.

 

Agfa Pan 100 and 400 are the Rollei 100 & 400.

 

Agfa Ortho 25 is the Rollei Ortho 25.

As mentioned above by the others, it is important to consider the fact that the spectral response of early films quite different from that of modern films. High blue sensitivity of early emulsions made it necessary to expose two plates if the sky was to be correctly exposed, one for the blue sky, the other for the rest of the field, and then print the two together in what was called combination printing. So the "speed" of the emulsion was quite different for sky versus trees. In the 1920's the films not only became faster, they became more sensitive to yellow-green (orthochromatic films). However, high red sensitivity was not, and still isn't as popular because of the need to load and process in absolute darkness. So comparison of film speed over the decades is a rather complicated question.

 

David

It's interesting to know what films & film speeds were available in the 1920s, for Barnak to use in the early Leicas.

 

But I wonder what they were in the 1930s 'golden age' of Leica photography - HCB, Kertesz, Brassai, etc.?

 

In US, when did Kodak's 35mm Super X & Super XX first appear?

 

I imagine the movie industry spurred film development & increase in film speeds.

 

(Re: the note above, on how films were rated: it pretty much boiled down to ASA & DIN?)

Shame this thread isn't gaining much momentum. I think I could learn a lot here. I do give the odd thought to film speeds back in the 'old' days. Goes to show that you don't always need ISO800 and f/1.4!