Dear all,
I've been a silent reader for some time. Now I am in need of some advice.
I've come upon some stronly deteriorated nitrate which is already sticky and I'd like to try to unwind it.
Has anyone had any success with that kind of problem?
Thanks.
Unwinding sticky nitrate
Re: Unwinding sticky nitrate
Cinelife,
Welcome to the posting side of the forum. As for your problem the film is already in stage 2 or 3 of deterioration.
This is point of no return for Nitrate based film stocks. The process of deterioration has become autocatalytic
in nature. So not much good news there. Also as the deterioration moves along the scale the temperature at
which it will spontaneous combusts gets lower, note home owners insurance do not cover nitrate film fires.
Also you are at a stage where damage to the images has already occurred but the action of acids on the sliver
crystals.
However, the film is also at a point there is nothing to lose either for trying. The big problem with sticking film
is this....The emulsion layer likes to stick or worse peal off the base and adhere to back of the adjacent wrap of film.
So this leaves with only two things you can do. To slowly unwinding the film as carefully as you can, and take your lumps
and any damage as it occurs. Or, you could try soaking the reel in some Vitafilm for a few days...It might loosen it but
a bit giving you less pain unwinding but this is kind of a last ditch effort with mixed results.
If you go the Vitafilm route remember it is not a cure all, but I have had good results with it over the years. It tends to
dry the film out by removing acids and free moisture. So something else will need to be done to make the film soft and
pliable again. I do suggest pure real camphor tablets.
Also when working with film soaked in Vitafilm it becomes like a wet noodle in the short term. It is very hard to handle.
You will need a set of hand rewinds, a way to then dry off extra Vitafilm off the film upon rewinding and a good flange
reel in order to wind the film. A flange reel has no holes or spokes, it is just a metal disc and is one sided only. And do
not wind the film tight, keep it just snug enough to keep it on the core, nothing more as there will still a be a good chance
of the film once again sticking to itself even worse then when you started as the Vitafilm starts to dry out. I had that
problem several times but each time it was a reel of film that really should have been thrown away long before I got it.
Would love to hear what others have done to over come this problem as more film stocks age this problem of sticking
film is going to become more wide spread.
pookybear
Welcome to the posting side of the forum. As for your problem the film is already in stage 2 or 3 of deterioration.
This is point of no return for Nitrate based film stocks. The process of deterioration has become autocatalytic
in nature. So not much good news there. Also as the deterioration moves along the scale the temperature at
which it will spontaneous combusts gets lower, note home owners insurance do not cover nitrate film fires.
Also you are at a stage where damage to the images has already occurred but the action of acids on the sliver
crystals.
However, the film is also at a point there is nothing to lose either for trying. The big problem with sticking film
is this....The emulsion layer likes to stick or worse peal off the base and adhere to back of the adjacent wrap of film.
So this leaves with only two things you can do. To slowly unwinding the film as carefully as you can, and take your lumps
and any damage as it occurs. Or, you could try soaking the reel in some Vitafilm for a few days...It might loosen it but
a bit giving you less pain unwinding but this is kind of a last ditch effort with mixed results.
If you go the Vitafilm route remember it is not a cure all, but I have had good results with it over the years. It tends to
dry the film out by removing acids and free moisture. So something else will need to be done to make the film soft and
pliable again. I do suggest pure real camphor tablets.
Also when working with film soaked in Vitafilm it becomes like a wet noodle in the short term. It is very hard to handle.
You will need a set of hand rewinds, a way to then dry off extra Vitafilm off the film upon rewinding and a good flange
reel in order to wind the film. A flange reel has no holes or spokes, it is just a metal disc and is one sided only. And do
not wind the film tight, keep it just snug enough to keep it on the core, nothing more as there will still a be a good chance
of the film once again sticking to itself even worse then when you started as the Vitafilm starts to dry out. I had that
problem several times but each time it was a reel of film that really should have been thrown away long before I got it.
Would love to hear what others have done to over come this problem as more film stocks age this problem of sticking
film is going to become more wide spread.
pookybear
Re: Unwinding sticky nitrate
Hello pookybear,
thank you for your thorough reply!
I would say the deterioration is level 4-5 already.
In 'Restoration of Motion Picture Film' by Read/Meyer a method of treating shrunken and brittle film with a glycerol/acetone/water mixture is described (evaporating not soaking), but it is mentioned not to use that on already sticky film, because of the danger of the emulsion peeling of completely. So I'm very reluctant to soak the film in anything.
Another method is described in the Australian preservation handbook: http://www.nfsa.gov.au/preservation/han ... mposition/" target="_blank
But I think this refers only to acetate, since there's a warning at the end not to use it on nitrate, because ethanol reacts exothermically with nitrate.
It might work with another solvent (like perklone perhaps), but only if the stickiness of the nitrate is actually due to the plasticiser moving through the emulsion and not because of the nitric acids eating up the gelatine, which I believe is the case.
Another method I have heard of is dehumidifying the film inside a desiccator with a drying agent, but how to make sure the emulsion doesn't dry on the wrong side of the carrier?
I'd also love to hear some other thoughts!
thank you for your thorough reply!
I would say the deterioration is level 4-5 already.
In 'Restoration of Motion Picture Film' by Read/Meyer a method of treating shrunken and brittle film with a glycerol/acetone/water mixture is described (evaporating not soaking), but it is mentioned not to use that on already sticky film, because of the danger of the emulsion peeling of completely. So I'm very reluctant to soak the film in anything.
Another method is described in the Australian preservation handbook: http://www.nfsa.gov.au/preservation/han ... mposition/" target="_blank
But I think this refers only to acetate, since there's a warning at the end not to use it on nitrate, because ethanol reacts exothermically with nitrate.
It might work with another solvent (like perklone perhaps), but only if the stickiness of the nitrate is actually due to the plasticiser moving through the emulsion and not because of the nitric acids eating up the gelatine, which I believe is the case.
Another method I have heard of is dehumidifying the film inside a desiccator with a drying agent, but how to make sure the emulsion doesn't dry on the wrong side of the carrier?
I'd also love to hear some other thoughts!
Re: Unwinding sticky nitrate
cinelife,
If it is already at stage 4 and taking in the account of it being nitrate film base. I would lay out the guess that
the nitrate acids have destroyed all the images on the film already. Even by stages 2 and 3 damage will occur. By
this stage of deterioration the film is highly unstable and releasing some very dangerous fumes in large amounts. I
will have to say this reel of film is a lost cause if it is truly in the state you say. If the film was in stage 5 all that
would be left is a can of dust. So it just becomes a disposal problem of hazardous waste. I have never seen any film
yet personally in stage 5 however, I have seen stage 4 in person. It was nothing more than a celluloid hockey puck
and nothing that could be saved.
That is a most interesting link you passed along with the dissolving of the blocking polymers. However, knowing that
any extra solution will attack what is left of the good film base means that this procedure is the final effort in saving
a film. Which in turns means that you need to do a transfer of the materials immediately as the master copy will soon
be destroyed by the residual effect of the unblocking treatment.
I too would agree with the Read/Meyer a method would be of no use in this case and most likely not to be used at all with
any film. There use to be a way of scrubbing off emulsion in order to make clear leader. Warm water with washing
soda was used in a soaking method. page 270 and 271 of The Bluebook of Projection the seventh edition. This works
on the fact that emulsion is highly hydrophilic in nature and should always be kept at 30% humidity. Raising the local
levels with additions water could lead to the start of base deterioration in good but dry films. This is the
reason of so many camphor based evaporation treatments. Also knowing that the Read/Meyer solution would be in
the form of drops applied to a blotting paper, and knowing the human nature of more is better. I can not recommend
that process for any film as the damage of excess can lead to damaged film from the increase in local humidity.
So back to your film in need...
Have been able to unwind any of the film so far? Do you know what material is on the reel? Possibly a name on a can?
Or if you are super lucky a title card you can see?
Pookybear
If it is already at stage 4 and taking in the account of it being nitrate film base. I would lay out the guess that
the nitrate acids have destroyed all the images on the film already. Even by stages 2 and 3 damage will occur. By
this stage of deterioration the film is highly unstable and releasing some very dangerous fumes in large amounts. I
will have to say this reel of film is a lost cause if it is truly in the state you say. If the film was in stage 5 all that
would be left is a can of dust. So it just becomes a disposal problem of hazardous waste. I have never seen any film
yet personally in stage 5 however, I have seen stage 4 in person. It was nothing more than a celluloid hockey puck
and nothing that could be saved.
That is a most interesting link you passed along with the dissolving of the blocking polymers. However, knowing that
any extra solution will attack what is left of the good film base means that this procedure is the final effort in saving
a film. Which in turns means that you need to do a transfer of the materials immediately as the master copy will soon
be destroyed by the residual effect of the unblocking treatment.
I too would agree with the Read/Meyer a method would be of no use in this case and most likely not to be used at all with
any film. There use to be a way of scrubbing off emulsion in order to make clear leader. Warm water with washing
soda was used in a soaking method. page 270 and 271 of The Bluebook of Projection the seventh edition. This works
on the fact that emulsion is highly hydrophilic in nature and should always be kept at 30% humidity. Raising the local
levels with additions water could lead to the start of base deterioration in good but dry films. This is the
reason of so many camphor based evaporation treatments. Also knowing that the Read/Meyer solution would be in
the form of drops applied to a blotting paper, and knowing the human nature of more is better. I can not recommend
that process for any film as the damage of excess can lead to damaged film from the increase in local humidity.
So back to your film in need...
Have been able to unwind any of the film so far? Do you know what material is on the reel? Possibly a name on a can?
Or if you are super lucky a title card you can see?
Pookybear
Re: Unwinding sticky nitrate
Hello pookybear,
I based the level on the following list:
Level 1 No deterioration.
Level 2 The negatives begin to yellow and mirror.
Level 3 The film becomes sticky and emits a strong noxious odor (nitric acid).
Level 4 The film can become an amber color and the image begins to fade.
Level 5 The film is soft and can weld to adjacent negatives, enclosures and photographs.
Level 6 The film can degenerate into a brownish acid powder.
I haven't started trying to unwind it yet, because I want to collect some more information on possible treatment first. I know the content. If I'll be able to unwind it at all, it will be printed immediately.
The Read/Meyer method works quite well for rehumidifying and deshrinking brittle film. We don't use it with paper though, but inside a desiccator as well. Also the process is reversible and the film has to be printed immediately... It will not improve longterm stability of course, so this is only a method for preparing decomposed film for printing.
A final effort of some kind will have to be made to transfer this film, but I'm hoping for some more input, before making a decision.
I based the level on the following list:
Level 1 No deterioration.
Level 2 The negatives begin to yellow and mirror.
Level 3 The film becomes sticky and emits a strong noxious odor (nitric acid).
Level 4 The film can become an amber color and the image begins to fade.
Level 5 The film is soft and can weld to adjacent negatives, enclosures and photographs.
Level 6 The film can degenerate into a brownish acid powder.
I haven't started trying to unwind it yet, because I want to collect some more information on possible treatment first. I know the content. If I'll be able to unwind it at all, it will be printed immediately.
The Read/Meyer method works quite well for rehumidifying and deshrinking brittle film. We don't use it with paper though, but inside a desiccator as well. Also the process is reversible and the film has to be printed immediately... It will not improve longterm stability of course, so this is only a method for preparing decomposed film for printing.
A final effort of some kind will have to be made to transfer this film, but I'm hoping for some more input, before making a decision.
Re: Unwinding sticky nitrate
cinelife,
There is an odd numbering system.... All the systems I have even seen have just been 5 stages not 6, leaving out
perfect film. However in reading you list of stages reading the comments on that list it is made for still photography.
and was taken from here: http://unfacilitated.preservation101.or ... itrate.asp" target="_blank" target="_blank" target="_blank
A List taken from film forever chapter 3 below. http://www.filmforever.org/chap3.html" target="_blank" target="_blank" target="_blank
Stage 1: Film has an amber discoloration with fading of the image. Faint noxious odor. Rust ring may form on inside of metal film cans.
Stage 2: Emulsion becomes adhesive and the film tends to stick together during unrolling. Faint noxious odor.
Stage 3: Portions of the film are soft, contain gas bubbles, and emit a noxious odor.
Stage 4: Entire film is soft and welded into a single mass, the surface may be covered with viscous froth, and a strong noxious odor is given off.
Stage 5: Film mass degenerates partially or entirely into a shock sensitive brownish acrid powder.
This is the list of stages I was using as a reference in my earlier posts so we can both be on the same page. Please note
that your number 1 is left out as there is no need to talk about perfect condition film. Who complains about that? Also
the difference in list and what they describe leads down to the point that movie film and still photographs are stored
in completely different ways.
As noted in your list with stage 4 your film just starts to fade. Do to the ability of photographs to "off gas" better then
rolled films which even by stage 1 in my list the images are already fading for exposure to nitric acid. And this is what
has me worried when you talk about sticking or welded film. What is left may just be blank!!
Also I do not see how the Read/Meyer method can be used for immediate situations. It would take most likely a year or
two for the slow evaporation method to penetrate the film stock and that would be based on 35mm stocks. Of course
sub sizes would go faster in the process. This is where amateurs can go a stray and use too much think things will go
faster and why I would not recommend it. I have been working on some reels of early safety stocks for over two years
now, slow and stead win the race.
But once again back to your case. You seem to be somewhere in the range of stages 2-4 just depends on how bad the
stickiness has become. Is this a lost film?
Pookybear
There is an odd numbering system.... All the systems I have even seen have just been 5 stages not 6, leaving out
perfect film. However in reading you list of stages reading the comments on that list it is made for still photography.
and was taken from here: http://unfacilitated.preservation101.or ... itrate.asp" target="_blank" target="_blank" target="_blank
A List taken from film forever chapter 3 below. http://www.filmforever.org/chap3.html" target="_blank" target="_blank" target="_blank
Stage 1: Film has an amber discoloration with fading of the image. Faint noxious odor. Rust ring may form on inside of metal film cans.
Stage 2: Emulsion becomes adhesive and the film tends to stick together during unrolling. Faint noxious odor.
Stage 3: Portions of the film are soft, contain gas bubbles, and emit a noxious odor.
Stage 4: Entire film is soft and welded into a single mass, the surface may be covered with viscous froth, and a strong noxious odor is given off.
Stage 5: Film mass degenerates partially or entirely into a shock sensitive brownish acrid powder.
This is the list of stages I was using as a reference in my earlier posts so we can both be on the same page. Please note
that your number 1 is left out as there is no need to talk about perfect condition film. Who complains about that? Also
the difference in list and what they describe leads down to the point that movie film and still photographs are stored
in completely different ways.
As noted in your list with stage 4 your film just starts to fade. Do to the ability of photographs to "off gas" better then
rolled films which even by stage 1 in my list the images are already fading for exposure to nitric acid. And this is what
has me worried when you talk about sticking or welded film. What is left may just be blank!!
Also I do not see how the Read/Meyer method can be used for immediate situations. It would take most likely a year or
two for the slow evaporation method to penetrate the film stock and that would be based on 35mm stocks. Of course
sub sizes would go faster in the process. This is where amateurs can go a stray and use too much think things will go
faster and why I would not recommend it. I have been working on some reels of early safety stocks for over two years
now, slow and stead win the race.
But once again back to your case. You seem to be somewhere in the range of stages 2-4 just depends on how bad the
stickiness has become. Is this a lost film?
Pookybear
Re: Unwinding sticky nitrate
This is the correct list of course. I had forgotten where to find it among my bookmarks chaos...
Based on this list it would be stage 3.
The rehumidification method (it has only been recorded by Read/Meyer in their book, but is being used by others like CNC for example) can be used that way. You've got to wind the film loosely and rewind it daily. Depending on the lenght of the film some progress can be made after a couple of days sometimes. At other times it takes weeks-months.
Anyway it will not help me in this case...
It's not a lost film in the sense of having been believed lost and suddenly found. It's the only version left though.
Based on this list it would be stage 3.
The rehumidification method (it has only been recorded by Read/Meyer in their book, but is being used by others like CNC for example) can be used that way. You've got to wind the film loosely and rewind it daily. Depending on the lenght of the film some progress can be made after a couple of days sometimes. At other times it takes weeks-months.
Anyway it will not help me in this case...
It's not a lost film in the sense of having been believed lost and suddenly found. It's the only version left though.
Re: Unwinding sticky nitrate
cinelife,
So it is a lost title then. What a heartbreak this is going to be. Even with safety stocks at similar point to stage 3
only 45% of films can be saved. The rest have lost all the images, literally just melting away. And that takes in
account the fact that acetic acid is a weak acid. The action of nitric acid is very aggressive and its action on the
silver is much more destructive.
The problem here is that the cellulose nitrate bonds are very strong. And if in fact it is the film sticking together (stage 3)
and trying to form a solid block of film (stage 4) it would be very near impossible to break these bonds. Most methods
either require extreme heat, in which the film of course can not stand. Or the use of solvents like, NMMO monohydrate
(N-Methylmorpholine-N-oxide), lithium chloride in dimethyl acetamide, or some of the hydrophilic ionic liquids.
However, this would completely dissolve the base away just leaving you with the emulsion. And furthermore I do
not know how these compounds would react with the emulsion itself.
There has been some work done with completely dissolving the base away from emulsion done in still photography. What
is done is the transfer of the emulsion to a new base material. However, I have no real information on this process, nor
do I think it has ever been applied to movie films just still photography.
"During early stages of decay, the film content can be rescued by transferring it to new film stock. Once the film becomes brittle it cannot be copied in its entirety. Because the gelatin emulsion usually stays intact during the degradation process, it is possible to save the image on sheet film using solvents to dissolve the base off the emulsion. Once the emulsion has been freed from the shrunken support, it can be photographed or transferred to a new support. Because of the solvents used, this is a delicate and potentially hazardous procedure and is an expensive process for a large collection. Degraded motion picture film cannot be restored in this way, but sheet films often can." from Reilly, James M. “Basic Strategy for Acetate Film Preservation.” Microform and Imaging Review 31 no. 4 (2002): 118
Thou the above was dealing with acetate film stocks but I first heard of the process being used on nitrate stocks. By all
accounts it could be applied to movie films that are reduced into just short strips of pictures and then rejoined again later.
However the time and cost are the limiting factors of such an endeavor. And knowing the fact that time is not on
your side in this case. There is no easy answer here with this film in its current the state of preservation.
Rather surprised no one else has chimed in on this matter. Any takers?
Pookybear
So it is a lost title then. What a heartbreak this is going to be. Even with safety stocks at similar point to stage 3
only 45% of films can be saved. The rest have lost all the images, literally just melting away. And that takes in
account the fact that acetic acid is a weak acid. The action of nitric acid is very aggressive and its action on the
silver is much more destructive.
The problem here is that the cellulose nitrate bonds are very strong. And if in fact it is the film sticking together (stage 3)
and trying to form a solid block of film (stage 4) it would be very near impossible to break these bonds. Most methods
either require extreme heat, in which the film of course can not stand. Or the use of solvents like, NMMO monohydrate
(N-Methylmorpholine-N-oxide), lithium chloride in dimethyl acetamide, or some of the hydrophilic ionic liquids.
However, this would completely dissolve the base away just leaving you with the emulsion. And furthermore I do
not know how these compounds would react with the emulsion itself.
There has been some work done with completely dissolving the base away from emulsion done in still photography. What
is done is the transfer of the emulsion to a new base material. However, I have no real information on this process, nor
do I think it has ever been applied to movie films just still photography.
"During early stages of decay, the film content can be rescued by transferring it to new film stock. Once the film becomes brittle it cannot be copied in its entirety. Because the gelatin emulsion usually stays intact during the degradation process, it is possible to save the image on sheet film using solvents to dissolve the base off the emulsion. Once the emulsion has been freed from the shrunken support, it can be photographed or transferred to a new support. Because of the solvents used, this is a delicate and potentially hazardous procedure and is an expensive process for a large collection. Degraded motion picture film cannot be restored in this way, but sheet films often can." from Reilly, James M. “Basic Strategy for Acetate Film Preservation.” Microform and Imaging Review 31 no. 4 (2002): 118
Thou the above was dealing with acetate film stocks but I first heard of the process being used on nitrate stocks. By all
accounts it could be applied to movie films that are reduced into just short strips of pictures and then rejoined again later.
However the time and cost are the limiting factors of such an endeavor. And knowing the fact that time is not on
your side in this case. There is no easy answer here with this film in its current the state of preservation.
Rather surprised no one else has chimed in on this matter. Any takers?
Pookybear
Re: Unwinding sticky nitrate
reto.ch does emulsion transfer as far as I know, but this will probably not be an option financially.
I know there is no easy answer, but I'm not giving up yet. Thank you for your comments.
I know there is no easy answer, but I'm not giving up yet. Thank you for your comments.
Re: Unwinding sticky nitrate
cinelife,
I shall them to my bookmarks, that is good information to have on hand. And Yes it seems you maybe right
back to my first post of soak in Vitafilm (that might help) or take your lumps and just unwind the film. Let me
know if you come up with something different like a light action solvent. I would be most interesting in knowing if
there was a creative solution to your problem here.
Pookybear
I shall them to my bookmarks, that is good information to have on hand. And Yes it seems you maybe right
back to my first post of soak in Vitafilm (that might help) or take your lumps and just unwind the film. Let me
know if you come up with something different like a light action solvent. I would be most interesting in knowing if
there was a creative solution to your problem here.
Pookybear
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Silencebound
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Re: Unwinding sticky nitrate
Simple remember, the Nitrate films does breathing with cool air like us humans do. Avoid using tight-clamped film cans. If it does, then it should be drilled with several small holes ( about 2mm ) at lower area of the can basket to emit out the gas and kept it off-gas all the time. I do this way. It won't rot if placed in any tin cans with some holes around it to be stored for long period.
Please click this URL https://www.facebook.com/Silencebound1/" target="_blank and become a new member to get instant informations and resourced topics.
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Spiny Norman
- Posts: 2370
- Joined: Tue Mar 18, 2008 8:21 am
Re: Unwinding sticky nitrate
There is also a liquid called Film Renew, but I have no experience with it.
In silent film, no-one can hear you scream.
This is nøt å signåture.™
This is nøt å signåture.™
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kaleidoscopeworld
- Posts: 258
- Joined: Sun Jul 19, 2009 12:13 am
Re: Unwinding sticky nitrate
The replies on this thread are pretty comprehensive, I was going to go to Read & Meyer too.
Not really relevant to the specific questions, but I'll add another couple of nitrate links:
Storage and Handling of Processed Nitrate Film
Management of Cellulose Nitrate and Cellulose Ester Film
Two other points - I've only seen it done for large-format negs (4x5 or 5x7), I don't know how it would scale down to 35mm. (It may be perfectly possible, I just haven't really looked into it). Also, I've only ever heard about this in the context of acetate film since it is in direct response to vinegar syndrome.
Not really relevant to the specific questions, but I'll add another couple of nitrate links:
Storage and Handling of Processed Nitrate Film
Management of Cellulose Nitrate and Cellulose Ester Film
I've seen this done. Some institutions are experimenting with, or have carried out, mass acetate base removal, but in general it's not easy to carry out because of all the chemicals involved. It is really hard for me to imagine anyone doing it for motion picture film. Maybe for a few frames of something really precious, but doing a whole reel of film would be pretty ridiculously impractical.pookybear wrote: There has been some work done with completely dissolving the base away from emulsion done in still photography. What
is done is the transfer of the emulsion to a new base material. However, I have no real information on this process, nor
do I think it has ever been applied to movie films just still photography.
"During early stages of decay, the film content can be rescued by transferring it to new film stock. Once the film becomes brittle it cannot be copied in its entirety. Because the gelatin emulsion usually stays intact during the degradation process, it is possible to save the image on sheet film using solvents to dissolve the base off the emulsion. Once the emulsion has been freed from the shrunken support, it can be photographed or transferred to a new support. Because of the solvents used, this is a delicate and potentially hazardous procedure and is an expensive process for a large collection. Degraded motion picture film cannot be restored in this way, but sheet films often can." from Reilly, James M. “Basic Strategy for Acetate Film Preservation.” Microform and Imaging Review 31 no. 4 (2002): 118
Two other points - I've only seen it done for large-format negs (4x5 or 5x7), I don't know how it would scale down to 35mm. (It may be perfectly possible, I just haven't really looked into it). Also, I've only ever heard about this in the context of acetate film since it is in direct response to vinegar syndrome.