Earliest Motion Picture Stocks.

[Matthew Buick]

Hello.

 

Does anyone know the speed of those earliest motion picture stocks (1891 - 1910)? All I know is they were nitrate based, orthochromatic, and were probably quite slow. The speed of these aincent stock is what I wanted to clarify, I know the earliest studios were built to harvest daylight, but I don't know whether this is just because electric lighting was very unreliable back then. The reason of Californian sunshine is why Hollywood was chosen for film production isn't it?

 

Blind interest. :P

[Charles MacDonald]

Hello.

 

Does anyone know the speed of those earliest motion picture stocks (1891 - 1910)? All I know is they were nitrate based, orthochromatic, and were probably quite slow. The speed of these aincent stock is what I wanted to clarify, I know the earliest studios were built to harvest daylight, but I don't know whether this is just because electric lighting was very unreliable back then. The reason of Californian sunshine is why Hollywood was chosen for film production isn't it?

I don't belive the camera stocks were very much differnet from 7302/5302 Fine grain release positive. The ortho stuff came later. Figure 3-4 ASA. and blue sensitive. Ortho was senitive to All Colours (except red)

[David Mullen ASC]

I don't belive the camera stocks were very much differnet from 7302/5302 Fine grain release positive. The ortho stuff came later. Figure 3-4 ASA. and blue sensitive. Ortho was senitive to All Colours (except red)

 

The ASA rating system didn't come about until the 1940's I think (they are somewhat similar to the Weston rating system used in the 1930's) so it's somewhat of a guess as to the speed of stocks back then. Plus early ortho movie stocks were developed by eye in red light until the density looked right, so they were being exposed at all sorts of levels (plus there were no light meters back then anyway.) I would guess that if the pan stocks in the early to mid 1930's were in that 25-40 ASA range, then possibly the stocks of the 1920's were half that, and the stocks of the 1910's were half that half...

[Patrick Neary]

Hi-

 

For anyone really interested in this stuff I highly recommend Richard Koszarski's "An Evening's Entertainment - The Age of the Silent Feature Picture, 1915-1928"

 

I'm in the middle of it right now, it's very well researched and has a nifty chapter on cameras, stock, labs, etc. of that period. He maintains that in 1915 Kodak had one orthochromatic negative stock (later labeled type 1201) with an asa around 24 (although ASA ratings weren't around at the time), and one print stock. He also says that labs initially resisted the panchromatic stock because they couldn't check the developing neg with their red lights.

[Matthew Buick]

I expected the speed of early film stocks to be low, 3-10 ASA is what I thought, seems I was correct.

 

I also knew ASA didn't come about until for a while afterwards, though I didn't know when. Weston Speed increments are a 1/3rd of an f stop off 'f' increments aren't they?

 

Thanks for your help everyone. :)

[Brian Pritchard]

I have been searching to try to find in the literature somewhere a film speed being quoted. I have searched through SMPTE Journals back to the 30's without much luck. The only useful fact I can find is in 'The Condensed Course in Motion Picture Photography' edited by Carl Louis Gregory from 1920. In this book he says that the normal exposure for Eastman B/W negative in sunlight was f4.5 at 1/50th sec.

 

I calculate that this equates to an ASA speed of 3. I believe, and I have to admit I am not a cameraman just a humble film lab technician, that the exposure at 1/50th sec for a 25 ASA film would be f11. So the estimate of 2 - 3 ASA was very accurate.

Brian

[Richardson Leao]

I have been searching to try to find in the literature somewhere a film speed being quoted. I have searched through SMPTE Journals back to the 30's without much luck. The only useful fact I can find is in 'The Condensed Course in Motion Picture Photography' edited by Carl Louis Gregory from 1920. In this book he says that the normal exposure for Eastman B/W negative in sunlight was f4.5 at 1/50th sec.

 

I calculate that this equates to an ASA speed of 3. I believe, and I have to admit I am not a cameraman just a humble film lab technician, that the exposure at 1/50th sec for a 25 ASA film would be f11. So the estimate of 2 - 3 ASA was very accurate.

Brian

 

I have followed (more or less) a recipe of photography chemistry for a colorblind stock (possibly similar to the stuff they have used in the early 1900), the results are here (I've posted this before):

 

 

there was some problems with the film coating as you can see, but just some remarks about the old stocks (as I've been learning recently quite a lot about them):

 

I have used thiosulphate sensitisation to get around iso 10-15, in the past, they've used 'active' gelatin, which generally meant unpredictable sensitivity. Also, the color sensitisation was also studied in the early 1900's. People have applied different dyes to silver halide crystals to get greater sensitivity to colors rather than blue and UV and that is documented since the late 1800's, but I guess the success came after the turning of the century.

[Hal Smith]

My 1930 Cinematographic Annual published by the ASC has a chapter titled "Sensitometry". It makes reference to sensitometry work by Hurter and Driffield and has Density Vs. Log Exposure charts that resemble modern Kodak technical data. An earlier "Painting with Light" chapter makes reference to an H & D sensitivity rating of 700 but doesn't have enough data to be able to figure out what that means. Hurter and Driffield developed a device for measuring sensitivity, density, Gamma (!), and latitude using a pentane flame and rotating sectored disk that could measure nine stops of latitude somewhere around 1890! My ASC manual quotes H & D sensitivities from that work at around 63.

 

I'll bet that sometime after 1930 there's an ASC article that relates H & D sensitivity to ASA.

 

Wikipedia has a short stub article at: http://en.wikipedia.org/wiki/Hurter_and_Driffield

 

There was a reprint of the 1920 survey article book mentioned in the Wikipedia article published in 1974. Copies are available for less than $20 and original editions go for a little over $100.

[Brian Pritchard]

I'll bet that sometime after 1930 there's an ASC article that relates H & D sensitivity to ASA.

 

The various film exposure ratings were introduced as follows:

H & D 1890

Scheiner 1894

Weston 1931

DIN 1934

1957 changed to match BS/ASA

BS/ASA 1947

 

H & D (Hurter and Driffield) were the people to invent the characteristic curve in 1889 and also invented their exposure rating system, firstly for plates.

 

The difficulty with the different systems is that they are not directly comparable as they all used different formulae for calculating the speed also they use different systems for the progression of speed. H & D gives a speed of 250 for a film and a film 10 times faster will have a speed of 2500. With DIN and Scheiner the progression is logarithmic.

 

300 H & D is roughly equivalent to 18 Scheiner, 8 DIN and 5 ASA. 2000 H & D is equivalent to 30 Scheiner, 20 DIN and 80 ASA.

 

In the 1940?s HP3 had a speed of 5000 H & D, 32 Scheiner, roughly 200 ASA.

 

 

Brian