Historical question about Cellulose Nitrate

My question about this type of film base is: when was this type of film base discarded?
I know what Wikipedia have about this, but my question comes from this situation. Yesterday I found several negatives of one photo/photographer house (one of the famous) of my home city. When the house ended, several assets were donated to the city museum.
I am working there, and in one storage rooms I found several boxes of negatives, several formats, even panoramic negatives.
A lot of the envelopes that have the negatives have the label "nitrate". So I think: woo, nitrate cellulose negatives here, in this room and how they are? Well I began to observe the various boxes of negatives. When I got home, I went to look information about the "nitrate films". Found what wiki says about how long they run in production, etc.
Today I when to see gain more negatives, all label "Nitrate". Saw 5x7 negatives and saw the notches.
I found Kodak super panchro-press type B, Kodak contrast process ortho, etc. Negatives have the year, or least the most of them have it. I saw from 1936 to 1954. In 1950, Kodak ended the production of nitrate cellulose film. But can I consider that the few negatives prior 1951 may be nitrate or all of them are acetate and the person labelled worng the negatives. Or the matter is not so black and white (with and with out pun intended) and in the middle, a few negatives may have this dangerous base and others not.
All of the negatives are photo film.

Rhodes said:

My question about this type of film base is: when was this type of film base discarded?

In 1950, Kodak ended the production of nitrate cellulose film.

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This base was phased out over decades, depending on use and manufacturer.

To my knowledge Kodak stopped with nitrate base in 1951.
In 1950 for amateur roll films.
In 1939 amd 1949 for sheet film, depending on type.

AgX said:

This base was phased out over decades, depending on use and manufacturer.
To my knowledge Kodak stopped with nitrate base in 1951.
In 1950 for amateur roll films

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Yes this is correct, each film base was replaced at a different time, to my knowledge the last film to switch away from Nitrate base was "verichrome", which became "Verichrome pan" I've developed some nitrate based verichrome with a date as late as 1953 expiration.

So I'm sure many of the films pre-1950 are in fact nitrate films.

But you will have to research each film to discover when the base was changed from Nitrate to "safety film" which means non-nitrate.

Even within Kodak the dates I gave above may not be true, as Kodak manufactured film in various parts of the world. And that phasing out might have been different.

I am not sure what this posting is about. If it is to establish certainty of the nature of the base the only way to find out for sure would be a physical/chemical testing of a snippet.

One might consider a "safety film" signing, but that might be copied during reproduction.

This post is just a historical curiousity of me and to get knowlage of photo history!
Many of the negatives do not have brand and ones that I saw just say kodak!

Sent from my GT-S6500D using Tapatalk 2

Hello,
many films with acetate base were marked as "safety film".

As said above, nitrocellulose was phased out over a few decades. Kodak was working on a replacement for it in the 19-teens. Most roll film was on safety film by the 30s, but not all. With the ones from my grandparents' house, it turned out to be a major hodge-podge. My great-grandfather did most of the photography and would buy a new camera frequently (unfortunately ditching the old usually) and with each came a new film size. So some from 1932 are safety film and some from the 40s are nitrocellulose. Argh!
With any sheets that have notch codes, check that the code matches with what any writing on them says. Nitrate ones could have been copied onto safety film and vice-versa. Somewhere here on APUG, I have a post about the old negatives found at my grandparents' house and in that thread are some links to more info. Somewhere on the web I found a great list, but I didn't bookmark it and have not been able to find it again.
I also found that lighting a sample on fire was not always a great test. I really wish I still worked at a lab to be able to get diphenylamine reagent - it tests for nitrates. The flame test was not as dramatic on some negs as I would like for a definitive test - some just fizzled out even though I was sure they were nitrate-based (gotta run a control so you know what to look for). How they've been stored could likely make a difference to how they react as well as how degraded they are.
Using a flatbed (Epson 4870), I've gotten decent scans of mine and I've gotten some ok contact prints.

Some MOVIE safety film will glow under a UV light, so if you can get a glow it is Safety base.

Thanks for the replies! I have time, I will look into more negatives!

AgX said:

This base was phased out over decades, depending on use and manufacturer.

To my knowledge Kodak stopped with nitrate base in 1951.
In 1950 for amateur roll films.
In 1939 amd 1949 for sheet film, depending on type.

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that souns right;my baby pictures 1954 were all taken with 'safety film':, which wasthe thing to do at the time

What about 1940s 4 x 5 film that has Kodak --Safety Film embossed on it but has the v notch code which I though was a nitrate indictator? Still trying to figure that out.

After several movie house fires that resulted in loss of life it was decided that this film base was just too dangerous. Stop the manufacture of cine film and amateur still film was soon to follow. Cellulose nitrate is also unstable and the films made from it were not archival. You would be surprised just how quickly it burns almost explosively. BTW gun cotton is also a type of cellulose nitrate. IIRC a few films held on notably Verichrome into the late 40's.

Gerald C Koch said:

IIRC a few films held on notably Verichrome into the late 40's.

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Hmmmm ... I still have some of my dad's negatives, and he shot non-pan Verichrome until it was discontinued. I think they're still in reasonably good shape so they may be Kodak Safety Film {tm}. (**WHOoooommmpf!**)

I still have to see degraded sheets of Nitrate based film. But I saw such sheets from Diacetate based film.

AgX said:

I still have to see degraded sheets of Nitrate based film. But I saw such sheets from Diacetate based film.

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My uncle worked as an illustrator for Walter Lantz and also briefly for Walt Disney. Unfortunately the outtakes he saved did not survive very well over the years. The film had shrunk and wrinkled and become Impossible to salvage.

Gerald C Koch said:

After several movie house fires that resulted in loss of life it was decided that this film base was just too dangerous. Stop the manufacture of cine film and amateur still film was soon to follow. Cellulose nitrate is also unstable and the films made from it were not archival. You would be surprised just how quickly it burns almost explosively. BTW gun cotton is also a type of cellulose nitrate. IIRC a few films held on notably Verichrome into the late 40's.

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Guncotton IS cellulose nitrate.

Single base smokeless gunpowder is cellulose nitrate, with some burning rate modifiers.
Don't play with nitrate film, especially by confining it.

What Gerald refers to is that there are different degrees of nitirification of cellulose.

the cleveland clinic fire was one of the
things that pushed kodak to phase out
flammable film. it isn't only the massive heat
that is dangerous but the toxic smoke.
if you do a flame test do it in a well ventillated area !

E. von Hoegh said:

Guncotton IS cellulose nitrate.

Single base smokeless gunpowder is cellulose nitrate, with some burning rate modifiers.
Don't play with nitrate film, especially by confining it.

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Gun cotton contains more nitrogen than the cellulose nitrate film stock. It all depends on the amount of nitration. Some texts differentiate the two as gun cotton being cellulose TRInitrate while film base is the DInitrate whereas celluloid is the MONOnitrate. These designations are only approximate and mostly a convenience. Which is why I made the distinction. Gun cotton will explode when ignited while film stock will burn vigorously.

Gerald C Koch said:

Gun cotton will explode when ignited while film stock will burn vigorously

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hi gerald
thanks for the distinctions !
what is collodion ?
i used to get bottles of it from my local pharma years ago
and it doesn't explode when ignited, but burns bright, hot and with
wicked black smoke ...

AgX said:

What Gerald refers to is that there are different degrees of nitirification of cellulose.

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Yes. Mono, di, and tri.

Gerald C Koch said:

Gun cotton contains more nitrogen than the cellulose nitrate film stock. It all depends on the amount of nitration. Some texts differentiate the two as gun cotton being cellulose TRInitrate while film base is the DInitrate whereas celluloid is the MONOnitrate. These designations are only approximate and mostly a convenience. Which is why I made the distinction. Gun cotton will explode when ignited while film stock will burn vigorously.

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Guncotton flashes instantly, it does not explode if ignited in loose form in open air. Confined, even slightly, the burning rate turns to detonation. As the term indicates, it is nitrated cotton fiber and is easily made from any pure cotton.

jnanian said:

hi gerald
thanks for the distinctions !
what is collodion ?
i used to get bottles of it from my local pharma years ago
and it doesn't explode when ignited, but burns bright, hot and with
wicked black smoke ...

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Collodion in the photographic sense is guncotton dissolved in a mix of ether and ethyl alcohol. You can still get it up here in the boonies, I think NuSkin is the brand

I knew that nitrocellulose was removed from film, but I did not realize that it was only relatively recently.

E. von Hoegh said:

Collodion in the photographic sense is guncotton dissolved in a mix of ether and ethyl alcohol. You can still get it up here in the boonies, I think NuSkin is the brand

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hi e von hoegh -- thanks !
would it be mono or di or tri?
when i documented an arsenal years ago
one of the places i spent time at was the nitrocellulose factory ( shack )
they brought pulped rags in and nitrated them in wooden vats
then rinsed them in alcohol and dissolved them in ether.
wicked dangerous ( understatement ) ... the nitrocellulose was extruded into pellets
and either used as an explosive charge ( with nitroglycerin ) or as a propellant.
i have always been amazed at how many uses nitrocellulose has had ...
its even used in the manufacture of blank lacquer plates for the record industry
i can just see florence nightingale saying " don't smoke that pipe too close to that arm you'll go up in flames"
or edison's lab after he stopped using wax cylinders...