Do Cels Need to "Breathe?"

[sensei]

I've heard cels should be allowed to 'breathe' and the opposite. Oxygen oxidizes paint, so wouldn't punching a hole and exposing the cel to air be bad? Or is completely sealing it off bad? I've heard both arguments and I never know which one to go by.

I've taken Maiko's question and started a new thread with it, as I'd like to hear some professional conservators' opinions on this issue.

From personal observation, the main source of intrinsic vice (the tendency of a cel to deteriorate over time) is the chemical activity of the paint. The trace lines most likely to fade are those completely encased in paint, and it is clear from some cels I've seen that certain color paints (greens, browns, oranges, yellows, and dark flesh colors) fade lines quicker than others. So leaving a hole in the bag to vent "fumes" would have no impact on this process.

Also, I've seen cel bags pucker badly when in direct contact with cel paint. Replace the bags, and the new bags pucker also. But the parts of the bag that are not in direct contact with the paint are not affected. So I believe that the puckering is not caused by toxic fumes but by the paint itself.

I do clip a corner of my cel bags, but not to let the cel breathe. Rather, as the cel is stored in a cel book (upright to minimize pressure), it is annoying to have a little bit of air trapped in each of the cel bags, as these 48 little balloons cumulatively begin to make the whole cel book act a little like an accordian. If you clip a corner, when you put the book away, the bit of air in each bag deflates and the book takes up less space. But, of course, the cel cannot "breathe" under these circumstances, as there is no air left in each bag. (Similarly, it's a bad idea to let a small child play with a cel bag, clipped corner or no.)

Other curators' opinions?

[Sky Rat]

I personally prefer to store my cels in bags that aren’t sealed at all, so there really is no need to clip a corner or punch a hole in it…

I didn’t start doing that to let the cels breathe though, I just had too many nerve wrecking moments where the adhesive on the bag would catch on the cels as I took them out to scan or change bags. I felt like I was risking damage too much by sealing the bags.

I am pretty interested to hear other people’s feedback on this topic though.

So far my personal experience is that all of my cels stored in bags in books (I’ve had them in bags both sealed and unsealed) have remained in the condition I got them (any damage was there when I first acquired it.) The only cel I’ve seen deteriorate was one I made the very unfortunate decision early in my collecting to frame. Even with UV shielding glass there was line fading due to light exposure. But I haven’t seen any noticeable difference in deterioration amongst my properly stored cels.

[zerospace]

I do the same as Sky Rat. I prefer to use bags that have no adhesive on the end, or if they do, I simply fold the end of the bag or leave it unsealed completely. I cringe anytime a cel sticks to the adhesive when being pulled out for scanning, bagging, or re-bagging. I especially cringe when this happens to a sketch!

I store cels in archival boxes if they are too large for my largest Itoyas, and I store standard-size cels in file boxes with acid free folders. All our cels are bagged somehow, while sketches are generally left unbagged (some sketch sets are bagged for organization purposes, but that's also why we have acid free folders). My husband and I store our entire collection in a closet (it takes up about 6+ file boxes, 4 archival boxes, a couple of 11x24 Itoyas and a couple of 17x24 Itoyas. When we want to enjoy our artwork, we just pull out the books and boxes ^_^.

Our storage method was born of necessity. We had to move away from Itoyas as our sole storage method because our collection is just too large. We would love to one day replace our file boxes with a nice big file cabinet, too .

I guess the short answer is that yes, we do let our cels breathe, but our reason for doing what we do isn't to really let them "breathe". Thus far, we've had excellent luck with our storage methods, as we haven't noticed any further deterioration of our cels or sketches. This thread did remind me, though, that it's very soon time to consider some new bags ...

[Keropi]

Early on, I liked bags with adhesive to seal them. But the sticky part kept getting stuck on the cel as I was putting in or taking them out of their bag. I went and cut the ends off the bags so the end of the bag was open ended and had no adhesive on them (not even having the ends folded down). That seems to have worked out the best in my case.

Those cels that I did that with now have easy entrance and exit!

That sounds like a certain line of lingerie.

[Sky Rat]

I went and cut the ends off the bags so the end of the bag was open ended and had no adhesive on them (not even having the ends folded down). That seems to have worked out the best in my case.

How do you cut the ends off yours?

I leave mine totally open ended too, not folding them over. I’ve considered cutting them down so that I don’t have so much extra plastic hanging out (I’ve bought a few cels that came in bags trimmed down and I quite liked that.) However I felt that cutting all of that plastic would dull my paper cutter blade beyond use for anything else. And I’d never be able to do a straight enough job with scissors, so I’ve never pursued the idea.

[Keropi]

How do you cut the ends off yours?

I just use a long scissors. It's not a perfectly straight cut, but it's decent enough for me. I ideally I wish I had one of those handle blade cutters where you bring the handle down, lay the bag down and cut it straight across. But those things are expensive and take up a lot of space.

[sensei]

I find that if you put the plastic bag in between the scissor blades and get the cut started, you can then pull the bag toward you (or push the scissors away), and without moving the blades you just slice through the rest of the bag in one quick motion. I learned this at the department store where I used to shop from watching clerks in the giftwrapping department cut Christmas wrapping paper.

Hint: not with the cel inside the bag.

[iceman57]

I've taken Maiko's question and started a new thread with it, as I'd like to hear some professional conservators' opinions on this issue.
From personal observation, the main source of intrinsic vice (the tendency of a cel to deteriorate over time) is the chemical activity of the paint. The trace lines most likely to fade are those completely encased in paint, and it is clear from some cels I've seen that certain color paints (greens, browns, oranges, yellows, and dark flesh colors) fade lines quicker than others.
So leaving a hole in the bag to vent "fumes" would have no impact on this process. Also, I've seen cel bags pucker badly when in direct contact with cel paint. Replace the bags, and the new bags pucker also.
But the parts of the bag that are not in direct contact with the paint are not affected. So I believe that the puckering is not caused by toxic fumes but by the paint itself.
I do clip a corner of my cel bags, but not to let the cel breathe. Rather, as the cel is stored in a cel book (upright to minimize pressure), it is annoying to have a little bit of air trapped in each of the cel bags, as these 48 little balloons cumulatively begin to make the whole cel book act a little like an accordian. If you clip a corner, when you put the book away, the bit of air in each bag deflates and the book takes up less space. But, of course, the cel cannot "breathe" under these circumstances, as there is no air left in each bag. (Similarly, it's a bad idea to let a small child play with a cel bag, clipped corner or no.)

Other curators' opinions?

Here are the data I collected over the last year with conservators' and completed with recent papers from the ASIFA and the UNESCO.
I'll reuse the different splitted part from Sensei note.

From personal observation, the main source of intrinsic vice (the tendency of a cel to deteriorate over time) is the chemical activity of the paint. The trace lines most likely to fade are those completely encased in paint, and it is clear from some cels I've seen that certain color paints (greens, browns, oranges, yellows, and dark flesh colors) fade lines quicker than others.

Brings us to the question of the damages source.
Q1. Is paint the root cause of acidic smell and line damages?
A1. No, it appears not to be accordingly to ASIFA papers, the cel itself catalyses after some stimulations (will not detailled would take a long thread) and start to emit acidic components (the smell) that affect the stucked layer on the cel (paint + xeroxed lines).

So leaving a hole in the bag to vent "fumes" would have no impact on this process. Also, I've seen cel bags pucker badly when in direct contact with cel paint. Replace the bags, and the new bags pucker also.
But the parts of the bag that are not in direct contact with the paint are not affected. So I believe that the puckering is not caused by toxic fumes but by the paint itself.

Brings us to the question of ventilation:
Q2. Do air breathe ameliorate the life of a cel?
A2. Yes, the more the cel is without air ventilation, the more the catalysis is running, able to contaminate close stored cel. Cel books grouping smelling cels are definitively a pure danger for non yet affected cels.

Brings us to the question of preservation:
Q3. Can I save my existing cel?
A3. No, sorry but once catalysis started THERE ARE NO EXISTING PROCEDURES TO STOP IT. UNESCO through ASIFA recommands to transfer on a new layer support.

Brings us to the question of transfer.
Q4. So, does it exist a way to transfer a cel paint and lines on a new cel?
A4. Yes, confirmed by a pro restaurator working on 12th century asian paintings. They are technics able to freeze the plastic and cut the thin layer of paint, recommandation is a transfer on polyester to multiply by four the lifetime. Price is definitively reserved for museum only.

And now the best part, by reducing catalysis elements, cels will durate your human life before being totally corrupted.
Brings us to 2 roads:
- If this is a personnal hobby, as says Doc Mc Brown in "Back to the Future" about danger of breaking spacetime continuity: "who cares" As there is no need to plan such conservation budget.
- If this is a family goal, money placement, insured items,... think right now about conservation budget which can really be expensive and drastically isolate smelly cel.

Coming back on storing and cel bags, conservator recommend to use certified polyester bags with a L system (one side corner opened).

[sugarcels]

No. Many of the bags my cels are in, are what they came in. I didn't know I was supposed to do anything I do keep them in special cel books, though. The larger ones are stored in the dark so that sunlight can't get them.

[sensei]

So to sum up:

1. Most Rubberslug curators do not cut holes in cel bags specifically to vent fumes, though most of the respondants added that they also do not seal bags up, for a variety of reasons.

2. iceman57, citing conservators with whom he has contact, argues strongly that cel bags should be vented to the air to ensure long-term preservation. In his view the source of intrinsic vice is the acetate base itself, which at times is unstable and the source of fumes that damage the art. The only permanent fix for this is to transfer the art to a new, archivally stable matrix, a costly process that is viable only for museums.

3. A more immediate risk is exposure to light, as even if UV-resistent glass is used, trace lines will fade quickly and visibly.

An unresolved issue, in my opinion, is why certain paint colors are more associated with fading than others. This is very easy to see in some cels that I own, where lines will be crisp and black up until a certain paint is used, then turn brown or even yellow in advanced cases. As these lines are completely covered with paint, the most logical culprits are the paint and the plastic, which contact the trace lines on either side.

iceman57 suggests that the plastic is the main agent, with acidic fumes seeping out of it into the poreous paint and fading the trace line in the process. However, if so, it would seem that the fading would occur at a similar rate over the entire face of the cel, regardless of the color paint on top.

It would also seem that the puckering of cel bags would occur more dramatically in contact with the cel, rather than with the paint, and would be seen on both sides of the bag rather than on just the back.

The chemistry of what happens inside a cel bag remains somewhat unclear to me. It's possible that the effects of light, the presence of acidic emissions from the acetate, and the chemistry of paint pigments could work together at different rates to react with the trace lines.

Also, I'm not aware of anyone looking closely at the content of the trace lines themselves. They consist of carbon powder, mixed with a polymer that is melted by the copier in the process of transferring the image to the matrix (in this case the acetate sheet).

This polymer does indeed emit fumes, which are the main source of "that new cel smell" that hits you when you open a cel bag. (My Madhouse cels still are redolent with this smell, even after two cel bag changes.) The polymer could be can be a styrene acrylate copolymer, a polyester resin, a styrene butadiene copolymer, or something else, according to Wikipedia.

I must admit I'm not enough of a chemist to know the archival properties of these compounds, but it's possible that line fading may involve a three-way reaction among the acetate, the polymer toner in the lines, and the pigment of the paint.

However, the consensus of curators seems to be that these bags should be opened in some way to vent air, though for a variety of reasons, some involving simple convenience.

[Sky Rat]

I would agree that certain paint colors seem to accelerate line fading. I’ve had cels with a lot of line fading…but it only occurred where the lines were touching yellow or orange paint. All the rest were still black.

I’ve also sort of formed the opinion that different animation studios use higher or lower quality materials. I have cels from some series which across the board all seem to have stayed in pristine condition. Other series which across the board the cels always seem to be really fragile. I can’t help suspecting that the animators of one series used higher quality paint than the other, etc.

[iceman57]

Yummy topic !!

iceman57, citing conservators with whom he has contact, argues strongly that cel bags should be vented to the air to ensure long-term preservation. In his view the source of intrinsic vice is the acetate base itself, which at times is unstable and the source of fumes that damage the art. The only permanent fix for this is to transfer the art to a new, archivally stable matrix, a costly process that is viable only for museums.

Whom he has contact, who worked with major European chemists on 12th century pigments, and paid too

A more immediate risk is exposure to light, as even if UV-resistent glass is used, trace lines will fade quickly and visibly.

This part I'm not in, from the different tests I made over the last year, acid damages faster than light.
Light damages are known from decades by conservators but on animation art and film conservation, acid is top priority, you may think about UV later

An unresolved issue, in my opinion, is why certain paint colors are more associated with fading than others. This is very easy to see in some cels that I own, where lines will be crisp and black up until a certain paint is used, then turn brown or even yellow in advanced cases. As these lines are completely covered with paint, the most logical culprits are the paint and the plastic, which contact the trace lines on either side.

iceman57 suggests that the plastic is the main agent, with acidic fumes seeping out of it into the poreous paint and fading the trace line in the process. However, if so, it would seem that the fading would occur at a similar rate over the entire face of the cel, regardless of the color paint on top.

Film industry through ASIFA and UNESCO fund, and especially national archivist are aware about this issue will rolls seeled in metallic boxes, that increases the damages.

The chemistry of what happens inside a cel bag remains somewhat unclear to me. It's possible that the effects of light, the presence of acidic emissions from the acetate, and the chemistry of paint pigments could work together at different rates to react with the trace lines.

I’ve also sort of formed the opinion that different animation studios use higher or lower quality materials. I have cels from some series which across the board all seem to have stayed in pristine condition. Other series which across the board the cels always seem to be really fragile. I can’t help suspecting that the animators of one series used higher quality paint than the other, etc.

They used the cheapest crap they could find, remember that we are talking about a production tool/machine and not about archives.
The unique arts supposed to be archived where model, to reuse in future TV series or films, so they did not focused about conservation at this time.

Also, I'm not aware of anyone looking closely at the content of the trace lines themselves. They consist of carbon powder, mixed with a polymer that is melted by the copier in the process of transferring the image to the matrix (in this case the acetate sheet).
This polymer does indeed emit fumes, which are the main source of "that new cel smell" that hits you when you open a cel bag. (My Madhouse cels still are redolent with this smell, even after two cel bag changes.) The polymer could be can be a styrene acrylate copolymer, a polyester resin, a styrene butadiene copolymer, or something else, according to Wikipedia.

Polymer react to different stimulus, main problem is to identify what kind of "magic powder" had been used in the mid-80s in Japan.
I'll say that Xerox company lab may offer interesting answers, anyone working there ?

I must admit I'm not enough of a chemist to know the archival properties of these compounds, but it's possible that line fading may involve a three-way reaction among the acetate, the polymer toner in the lines, and the pigment of the paint.

I would agree that certain paint colors seem to accelerate line fading. I’ve had cels with a lot of line fading but it only occurred where the lines were touching yellow or orange paint. All the rest were still black.

It appears that the catalysis affects differently some colors, on idea is that to lighten some colors they had been mixed with polymers too.
I bet on this triple curse too, now fact is to know what enemy fight first on short term to save the art, mid term and long term.
Here are actual conclusions : 1st ACID, 2nd LIGHT, 3rd PAINT.

But... to overpass this, now the OFF TOPIC START

I'll use a more artistic example...
http://en.wikipedia.org/wiki/File:Gilbe ... rt_003.jpg
(Gilbert Stuart, George Washington, also known as The Athenaeum and the The Unfinished Portrait, 1796, is his most celebrated and famous work.)

Do we really need to restore this painting of GW ?
No because this is part of history
Brings me to questions : Is line fading not simply a part of the reality of anime art life ? And consequently can we stop the time to act?
Whenever using polyester layer, acid free plastic bags perfectly ventilated, UV free glass, and polymer free painting... aren't cel simply cursed?

END OFF TOPIC

[Sky Rat]

This part I'm not in, from the different tests I made over the last year, acid damages faster than light.
Light damages are known from decades by conservators but on animation art and film conservation, acid is top priority, you may think about UV later

I’ve seen drastic damage occur in less than a year, with glass that a professional framer told me would protect against UV damage. Both with copy lines fading on a cel, and copic-type marker coloring fading on an original sketch.

Both pieces were kept in a room where the blinds were usually drawn too, they weren’t even regularly exposed to direct light.

UV damage can happen very very quickly, I consider it a pretty high priority to prevent.

[iceman57]

Interesting feedback, as wrote up and confirmed by conservator light can affect. Fact is that the line catalysis was activated by acid in Japan years ago and not reversible (can be 20-30 years for some cels). Additionnaly high temperature as moisture increases the process.

Do you live in a climatic region that has the 2 criterias ?
Were they framed together ?
What about backboard ? Wooden or alcalyn barrier ?
What about art, mounted or in direct contact with glass & backboard ?

[Keropi]

I'd be curious to find out why the warmer colors tend to fade lines faster than the cooler colors. For example, I have a heck of a lot more line fading in brown and red colors compared to my lines in purple or blue.

It's very strange why that is.