Yellowing of CG sketches

[ginga123]

has anyone encountered or experienced this? it's a partial cut and it's very, very slowly starting to spread to other sketches within the cut. no smell, appears on the edges, and has a coffee-stain-like colour. does this mean the paper is highly acidic and i need to separate each sketch within the set to prevent further damage?

[Keropi]

How is the humidity in the room that you store the sketches in and how old are those sketches? Are they old?

I've had non-sketch paper grow foxing stains on them, but it was caused by the humidity and low ventilation in my room. My mom gets foxing stains on her papers in Hawaii (especially) when she stores them in low ventilation areas such as the bottom of drawers. It's a lot more humid out there than it is out here in Los Angeles.

Some of the paper foxing I had transferred to the papers below and above them. I think it was caused by the tiny amount of iron deposits that is in the paper.

[ginga123]

the humidity is relatively normal in room where i store both cg and cels. the sketches that have these "stains" are roughly 10 years old and i kept them in a bag sealed with its sequence mates, being a partial cut. i do live in TN, and our summers are smothered in humidity. this year wasn't as hot as it is normally. in fact, we are already experiencing signs of a early fall with days of no humidity and cool fall winds at 80 degrees.

as a precaution, i've taken them out of that bag and have them sitting in a very cool room exposed to open air. i've checked other cg sketches from the other shows and didn't see any with the same "stains."

is this reversible or will it deteriorate further?

[Keropi]

If it's foxing I don't think it's reversible. You should be able to keep it from getting worse though.

Is there any way to take a picture of how it looks like?

[sensei]

This is one possibility: I have seen sketches (gengas) that were obviously done on a pad of paper that was put together with something like that "sticky note" adhesive. Presumably the artist would do sketches on the top sheet, then pull it off the top and do the next sketch. Unfortunately, "sticky note" adhesive is not stable and browns significantly with age, just like celotape adhesive. So if the staining on all the sketches in on the top, the side with the registration holes, then that might be the cause.

If it's appearing on all four sides, then the sketch has probably been exposed to some atmospheric pollutant in the past, which the paper has taken up. Or possibly been stored inappropriately, such as in a corrugated cardboard box in a storage facility with no A/C. In any case, I'd say layer the sketches with microchamber paper and put them in a fresh bag. Yes, probably the stain is irreversible, but at least microchamber paper will neutralize the acid and check the spreading.

Please do keep us in touch and share a photo if practical.

[ginga123]

Photo won't load from my phone, too high resolution. Able to crop this one & post.

[sensei]

It does look like that A5 has gotten its right edge dipped into something that is acidic, and that substance has gravitated to the two sketches above and the one underneath. I'd certainly isolate the most affected sketch as the likely source of the contaminant and bag it separately with a sheet of microchamber paper. Then layer the others with the same paper and rebag. If possible, store in a cool place to slow any further chemical reactions.

A good reminder to all of us to physically inspect our art on a regular basis, looking for trouble.

[Keropi]

Hmm...at first glance, it does look like foxing. Foxing is usually rust colored, but sometimes it gets darker than that. But I'd check into Sensei's concerns as well.

Was that side of the paper that was exposed the most to the open air? Have you lived in the same place for awhile? Is this the only paper you've noticed this to be happening with in that room?

Foxing might take years to fully manifest itself. The damage is cumulative, but it sounds like this happened pretty quickly in your case.

EDIT:

Actually some websites say that foxing (if that is indeed what it is) IS reversible through professional restoration - though there is some risk if an attempt is made on it (just like many other professional paper restorations).

[ginga123]

I moved into this apartment last year. this set was completely sealed when I moved. The only time I opened it was to add sketches A8 thru A 11, bc I bought those at auction around this time last year. I did notice a small stain on A 1 at the time, but thought it was a spill. I guess guess I was mistaken. Only the first portion is affected. These have always been & no other edels or sketches seem to beedbe effected

Where can I purchase micro chamber paper? i'd like to take care of this asap bc I just purchased the remaining cut of this cg sketch set online a few days ago. I've read that you could iron out the stain using chalk & a warm iron, not sure if that would work

[sensei]

Where can I purchase micro chamber paper?

This is where I get it.. I tend to get either the 100 or 250 size as that's more economical than the 50 sheet size. Shipping is free E of the Mississippi, 10% extra west of it. I also get cel bags from the same source and have never had a problem with them.

[cutiebunny]

Just in case BagsUnlimited is out (they were when I ordered a couple months ago), there's a seller on E-bay that sells larger sizes of microchamber paper for pretty reasonable as well. Their ID was investment-comic-supplies and I received the item within a couple days of buying it.

[ginga123]

thanks, ill get on this right away and keep y'all posted. i remember that my last place of storage was quite a bit warmer compared to what i have now and where i live. i wonder if i accidentally exposed these sketches to a "hostile" pollutant when i added the extra cuts or the change in temperature had an effect on the set?? this is one of my favorite genga sets, i'd dislike to see the whole thing turn brown on me

im gonna recheck my stuff again tomorrow!

[sensei]

thanks, ill get on this right away and keep y'all posted. i remember that my last place of storage was quite a bit warmer compared to what i have now and where i live. i wonder if i accidentally exposed these sketches to a "hostile" pollutant when i added the extra cuts or the change in temperature had an effect on the set??

While curators should aim for a stable storage environment, I'm guessing that it wasn't your fault. More likely someone at the studio was careless and let the edge of that sheet get saturated with sake or lime soda or Sudafed or cleaning compound. They were means to an end (the finished digital footage of that scene) and so once this was finished the paper was trash. The contamination might have occurred in the dumpster or trash basket that someone pulled the sheets out of when no one was looking.