Film Speeds of The Past

kb3lms · Jul 5, 2013

The current state of home based emulsion making seems to be able to fairly easily get to ISO speeds as fast as 40 or maybe 50. Some have reported speeds up to 80 and even 100. My current emulsion brew is about 40. This got me to wondering: in today's measurements how did commercial films of the 1920's, 30's and 40's or even earlier compare? I recall hearing that film speed at the time was rated more conservatively than today. I'm specifically interested in black and white films.

My Kodak Tourist folder that I believe my father purchased new in 1947 has an exposure guide on the back listing three Kodak b/w films of the day: Super-XX, Plus-X and Verichrome. (Non-say PAN so I do not know if they were panchromatic films or not.) Going by the "Sunny 16" rule for an average subject in bright daylight, I would guess the speeds of these films as follows:

Super-XX 50 (1/50th @ f/16)
Plus-X 25 (1/25th @ f/16)
Verichrome 25

(Kodacolor is also listed and I would put that at 25 as well.) Does anyone have any data on other films?

Also, do we have any ideas about the manufacturing process of these b/w films? Were they SRAD's or made by other processes?

-- Jason

desertrat · Jul 5, 2013

If you don't mind doing some cross referencing and calculating, you can download this book from Archive.org:

http://archive.org/details/photographicfact00wall

Most of the popular films and plates available in 1924 are listed with speed numbers that don't correlate well to anything we use today. However, there is also a guide number listed for each product that can be plugged into the exposure tables elsewhere in the text to get sunny 16 exposure values. It's been awhile since I looked any of these up, but the fastest panchromatic emulsion I checked would have been about ISO 25. Most of the panchromatic emulsions were ISO 10 or less.

bsdunek · Jul 5, 2013

Here is a chart that compares film speeds. DIN, ASA/ISO, GE & Weston. Should help a little.
http://www.westonmeter.org.uk/speeds.htm

Gerald C Koch · Jul 5, 2013

Commercial manufactures such as Kodak, Agfa, etc. have long had access to manufacturing methods and chemicals that are not available to the average person. This allowed them to achieve higher film speeds in their emulsions. You are right that in the past films speeds were set more conservatively. This was done to prevent underexposure and insure that the user always got an image. Remember that light meters were not common or very accurate at this time. This practice also allowed products such as Acufine and Diafine to claim speed increases that weren't actually true.

kb3lms · Jul 15, 2013

Thanks for the responses everyone. So it would appear that our efforts compare fairly well with the products of the early 20th century. If only I could coat as well as they did then!

StoneNYC · Jul 15, 2013

kb3lms said:
Thanks for the responses everyone. So it would appear that our efforts compare fairly well with the products of the early 20th century. If only I could coat as well as they did then!

Film speeds were

Super XX 200ASA
Plus X 125ASA
Verichrome 125ASA

As far as know (I've been wrong more than once) those are the speeds GIVEN by film companies, but yes there was a change in ASA speed at one point. Basically they would rather you OVER expose, than under, and I think that means at one point 100 speed was really 200 speed at today's standards. But I don't know when that cutoff was, and there were different versions of at least plus-x and verichrome so they may have really been 400 and 250 speeds at today's standards.

That's my understanding.

~Stone | Sent w/ iPhone using Tapatalk

MattKing · Jul 15, 2013

The change in ASA speeds arose because they changed the ASA standard.

From Wikipedia:

"The ASA standard underwent a major revision in 1960 with ASA PH2.5-1960, when the method to determine film speed was refined and previously applied safety factors against under-exposure were abandoned, effectively doubling the nominal speed of many black-and-white negative films. For example, an Ilford HP3 that has been rated at 200 ASA before 1960 was labeled 400 ASA afterwards without any change to the emulsion. Similar changes were applied to the DIN system with DIN 4512:1961-10 and the BS system with BS 1380:1963 in the following years."

StoneNYC · Jul 15, 2013

MattKing said:
The change in ASA speeds arose because they changed the ASA standard.

From Wikipedia:

"The ASA standard underwent a major revision in 1960 with ASA PH2.5-1960, when the method to determine film speed was refined and previously applied safety factors against under-exposure were abandoned, effectively doubling the nominal speed of many black-and-white negative films. For example, an Ilford HP3 that has been rated at 200 ASA before 1960 was labeled 400 ASA afterwards without any change to the emulsion. Similar changes were applied to the DIN system with DIN 4512:1961-10 and the BS system with BS 1380:1963 in the following years."

So then what I said above is correct? (For once...haha)

EDIT: well I know Plus-X is 125 on the NEW standard so does that mean it WAS 64ASA before?

~Stone | Sent w/ iPhone using Tapatalk

kb3lms · Jul 15, 2013

Stone,

The Plus-X speed I am referencing was in 1947. By the Sunny 16 rule according to my Kodak Tourist the speed would have been 25 (1/25th @ F/16) in today's terms per the exposure guide built into the back of the camera.

I have no idea what they gave as the film speed at the time.

-- Jason

MattKing · Jul 15, 2013

StoneNYC said:
So then what I said above is correct? (For once...haha)

EDIT: well I know Plus-X is 125 on the NEW standard so does that mean it WAS 64ASA before?

~Stone | Sent w/ iPhone using Tapatalk

In addition to the change in standards, some of the films changed over time as the technology improved, and those changes included changes in sensitivity.

In some cases, old films were replaced with new films with different names. In other cases the names didn't change.

Like Vericolour, which went from ASA 125 to ASA 160, and was still called Vericolour.

Although that may have been when it went from Vericolour I to Vericolour II (or was it II to III?).

StoneNYC · Jul 16, 2013

MattKing said:
In addition to the change in standards, some of the films changed over time as the technology improved, and those changes included changes in sensitivity.

In some cases, old films were replaced with new films with different names. In other cases the names didn't change.

Like Vericolour, which went from ASA 125 to ASA 160, and was still called Vericolour.

Although that may have been when it went from Vericolour I to Vericolour II (or was it II to III?).

Lol that still doesn't answer the OP's question about the 3 films listed on his camera haha

~Stone | Sent w/ iPhone using Tapatalk

MattKing · Jul 16, 2013

StoneNYC said:
Lol that still doesn't answer the OP's question about the 3 films listed on his camera haha

~Stone | Sent w/ iPhone using Tapatalk

No, but it does help explain why the film names themselves are of such little help.

Another factor that needs to be considered as well is that what constitutes a standard for exposure for "snapshot" cameras now may very well be significantly different than the standard when the OP's camera was current.

I have a few negatives from around that period, and they look today to be both over-exposed and over-developed. I believe that manufacturer's recommendations then were oriented toward drug store processing and avoiding under-exposure, at all costs.

So I would be careful about using those recommendations without backing it up with testing.

RichardH · Jul 16, 2013

Like Vericolour, which went from ASA 125 to ASA 160, and was still called Vericolour.

Although that may have been when it went from Vericolour I to Vericolour II (or was it II to III?).[/QUOTE]

Matt, I think it was II to III they made that change. I remember ordering some II and they sent III. I was nervous since I hadn't tested the new film and had to shoot a wedding the next day. I think I shot it at 100 ASA just to make sure I had something. I couldn't tell a difference except the colors had to be reprogrammed into the printers and analyzers. They were a little off from the II film. I'm not really sure it wasn't just a base change in the new version. My memory is a little foggy since it has been a long time ago.

Richard

kb3lms · Jul 16, 2013

I have a few negatives from around that period, and they look today to be both over-exposed and over-developed.

So do I as well as some from the teens and 1920's and I would agree that they certainly look over-developed. Actually, they look almost exactly like my own hand-made film when it is over-developed which is one reason I believe the technology (or lack thereof) behind them is basically the same. The film I make now and especially the negatives I have from the 20's look very, very similar in most respects and that's where this whole question really started.

Also, FWIW, there is an unopened box of 120 Super-XX of 1948 vintage listed on eBay right now. The seller has good,clear photos of the box and no speed is shown on the box at all. If the seller's asking prices weren't quite so high I would consider buying a few boxes to investigate.

Googling Super-XX, I have seen ASA speeds given from 64 to 200. I could go along with 64 but IDK about 200. Again though, maybe in 1947 they were still intentionally overexposing and the Sunny 16 rule doesn't quite apply. I'm not really sure this model of the Tourist (with the anaston lens) was considered a mass snapshot camera.

StoneNYC · Jul 16, 2013

I could swear super XX is 200 ASA because the SUPER was because it was "fast" now could have been 100ASA before the change in standard lol

~Stone | Sent w/ iPhone using Tapatalk

MattKing · Jul 16, 2013

Looking at the manual for the Kodak Tourist: http://www.cameramanuals.org/kodak_pdf/kodak_tourist.pdf

Interpolating from the recommendations there, and using Sunny 16 as the standard, I read the sensitivities of Verichrome Pan, Plus-X and Kodacolor to be equivalent to the current ISO of 25, whereas Super XX sensitivity appears to have been equivalent to the current ISO of 50.

This is the same as Jason's initial observations.

StoneNYC · Jul 16, 2013

MattKing said:
Looking at the manual for the Kodak Tourist: http://www.cameramanuals.org/kodak_pdf/kodak_tourist.pdf

Interpolating from the recommendations there, and using Sunny 16 as the standard, I read the sensitivities of Verichrome Pan, Plus-X and Kodacolor to be equivalent to the current ISO of 25, whereas Super XX sensitivity appears to have been equivalent to the current ISO of 50.

This is the same as Jason's initial observations.

Well then I may have way under-exposed my verichrome pan 127 roll just now LOL shooting it at EI16 based on an assumed ASA of 64 (before the standard change).

~Stone | Sent w/ iPhone using Tapatalk

kb3lms · Jul 16, 2013

WOW! Thanks, Matt. I never looked for a manual before - although I have been on that site many times.

Alan Johnson · Jul 16, 2013

From Wall's Dictionary of Photography 16th ed c1943:
"Most makers of film offer films of four different types,two orthochromatic and two panchromatic.The first two are the ordinary or standard film speed of about 25 degrees Scheiner....and the chrome film of about double the speed of the ordinary film.....they are known as chrome films....Verichrome,Isochrom,Selochrome etc.Of the panchromatic films one,in most makes sold as a fine grain film, has a speed that is usually between that of the chrome and ordinary films, while the speed of the other is usually about double that of the chrome film."
The table converts degrees Scheiner to ASA, my guess that it is old ASA,not sure on this.Scheiner is very likely 25 European, it is a UK book.

Dead Link Removed

Jim Noel · Jul 16, 2013

StoneNYC said:
I could swear super XX is 200 ASA because the SUPER was because it was "fast" now could have been 100ASA before the change in standard lol

~Stone | Sent w/ iPhone using Tapatalk

Super XX was not rated at 200. It was rated at 100 Weston. I still have a little bit left and continue to use that speed. I don't bother to convert it to ISO/ASA because one of my meters is in Weston ratings. No, Weston ratings had nothing to do with Edward or his sons.

MattKing · Jul 16, 2013

kb3lms said:
WOW! Thanks, Matt. I never looked for a manual before - although I have been on that site many times.

You are welcome.

I think I've been on Mike Butkus' site so often that I've memorized part of it.

MattKing · Jul 16, 2013

StoneNYC said:
Well then I may have way under-exposed my verichrome pan 127 roll just now LOL shooting it at EI16 based on an assumed ASA of 64 (before the standard change).

~Stone | Sent w/ iPhone using Tapatalk

It depends on how old the film is. The speeds changed over time.

Also, don't confuse information about Verichrome with information about Verichrome Pan.

I expect the 127 Verichrome Pan I shot in the Brownie Starmite II I was given for my birthday in 1964 had an ASA of 64.

Photo Engineer · Jul 16, 2013

Sorry, but I did not read all of these "expert" posts. The problem is that they don't take into account spectral sensitivity. So, you may make an ISO 40 emulsion that is color blind but might be ISO 100 if pan sensitized. Ortho changes the picture as well.

PE

StoneNYC · Jul 16, 2013

Jim Noel said:
Super XX was not rated at 200. It was rated at 100 Weston. I still have a little bit left and continue to use that speed. I don't bother to convert it to ISO/ASA because one of my meters is in Weston ratings. No, Weston ratings had nothing to do with Edward or his sons.

But isn't Weston 100 = ASA200 in today's standard?

~Stone | Sent w/ iPhone using Tapatalk

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