March 18, 2003
This posting was not originally intended to be this long, sorry. It kind'a grew.
. . . I recommend getting a coffee or something . . .
I am assuming that the "Canadian group" Nona refers to is the Canadian Conservation Institute, a federal government research and conservation agency within Culture and Heritage Canada.
CCI is the Canadian technical resource and repository of expertise on scientific considerations about preserving culture. CCI is well known for its good work, and is very highly respected internationally. Outside of Canada, CCI is used, from time to time, as a research and consulting resource by various international concerns spanning the globe, including U.S. governmental agencies, the Smithsonian, etc. . . . even PPFA and FACTS.
The various scientists and conservators who constitute CCI are a wonderful group of people who will go to great lengths to be helpful. These truly good folks will willingly, unselfishly, and openly provide research data, technical information, and perhaps from time to time, their own opinions - all is valued. Thank you CCI for your cheerful help!
The subject of foamboard has been addressed in The Grumble many, many times before. For a worthwhile review, refer to the archives - there was a lot of timely material posted.
This posting is not intended to be suggestive that it is the result of a definitive study. I have tried to be as "un-technical" as possible. Discussions of this nature should always make allowances for the degree to which one interprets data, viewed against individual operational practicality - this I have tried to do.
Notwithstanding research by various CCI scientists at various times, CCI does not project an official policy concerning foamboard usage in CP framing. It is my understanding that this is so because CCI has not conducted an in-house study concerning foam and CP framing. Therefore, CCI cannot recommend its use.
Foamboard is made up of a polystyrene core sandwiched between outer layers of paper. Depending upon the manufacturer, an adhesive may or may not be used to bond the papers to the core, and may be of varying chemical makeup, some being harmful, some being benign. The papers may or may not be "acid-free", may or may not be chlorinated, and may or may not be buffered. N&B's high-end foamboard employs third-party "Zeolite" technology and is labelled "ArtCare."
"Regular", "acid-free", "rag", and "ArtCare" foamboards all use essentially the same core i.e. polystyrene. The main difference is in the nature of the outer shell papers.
The last time (two?years ago) foamboard was Grumble queried, CCI did not have a problem with the papers used in "conservation quality" foam board. Concerns expressed at that time were: the risk of continued out-gassing of residual monomers (pentane or other chemicals - just smell the stuff when fresh), the nature of the adhesive (if any) used to bond the papers to the core (PVA's may breakdown and may produce acids), and the effects of deterioration by UV and heat - plus the constant breakdown factor over time i.e. just like you and I, polystyrene ages and over time, breaks down.
Conservators, being somewhat conservative people within our society, would rather be safe than sorry. Therefore, my understanding is that CCI's position on the subject was based upon the fact that interaction between foamboard and fine art had not been definitively and formally studied in-house. Therefore foamboard could not be considered a CP quality material - hence the objection to using foamboard in CP packages. Since there are known safe alternative materials e.g. Coroplast, the question of a formal research project into the use of foamboard may remain a matter of curiosity and not of necessity.
Some manufacturers may use an adhesive to bond the shell paper to the polystyrene core, or alternatively, the paper may be applied while the core is still fluid and tacky at the time it is extruded. From a CP perspective, the latter method is preferable because nothing else is added to the chemical menu. Both the "Regular" and "ArtCare" foamboards manufactured by N&B are made using the latter method - the good news is that, in consequence, potential paper adhesive problems are not an issue with N&B foamboards.
Polystyrene can break down under UV and heat conditions, and normal ageing. Breakdown may create a dust or crumbing problem and may emit harmful compounds. Of particular concern to conservators is the tendency of the breakdown products to create various unstable molecules, some of which produce the yellowing or browning phenomenon that can be readily seen in old foamboard samples.
It is unknown, with great certainty, just how these unstable molecules affect fine art within a framing package because there are many variables: what kind of art? what kind of media are present? What are the circumstances? The potential for damage needs to be considered because these unstable molecules want to chemically bond with something, and the art being handy, may provide a suitable target. . . or they may not present a problem - they may already have bonded with something else e.g. oxygen from the atmosphere, and have become stabilized - but under what specific circumstances can the art be risked?
Please note that it is acknowledged that the likelihood of UV or accelerated heat induced damage to polystyrene, while it is inside a frame package, is minimal, and risk is therefore reduced . . . but there is still the matter of natural ageing, and all its variances, to contend with.
Although foamboard papers may start out with an alkaline pH there is no guarantee that the pH will stay alkaline.
I have two samples of foamboard which were produced circa 1996. One sample is N&B "Regular" foamboard, the other is N&B "ArtCare." These two samples are used daily for demonstration purposes and are not in a sealed frame package i.e. they are exposed to the atmosphere.
In January 1996, the regular foamboard pH tested "greater than" 7.0. By March 1996 it tested "lower than" 7.0. In January 1997 the regular foam board pH tested "considerably lower than" 7.0.
In January 1997, the ArtCare foamboard pH was "considerably greater than" 7.0. In January 2002, the ArtCare pH dropped to a mere "greater than" 7.0, where it appears to be sitting today.
Test samples of rag and acid-free foamboards were thrown out some time ago because their results were similar to the regular matboard results i.e. the pH rapidly changed from greater than 7.0 to less than 7.0 and because I do not use them in my work.
This mini test proves only that the ArtCare stays alkaline longer than regular foamboard, speculating that its buffering agent is only slowly being depleted.
So what does this tell us?
This tells us that no matter what other people say, in establishing an operational policy, you have to be guided by what information you understand, and by your own circumstances - tempered, of course, with a great deal of common sense. The final decision is yours, and yours alone.
I do not stock regular foamboard. Most of my work is CP, therefore it is my policy to employ only techniques and materials considered CP. I do not stock "acid-free" and "rag" foams because they performed no better than regular foam, and cost more. However, I do stock ArtCare foam, and only ArtCare foamboard. Would I warehouse my ArtCare foamboard near electric motors? No! Ozone is detrimental to the polystyrene. How do I know ozone is bad for polystyrene? . . . because I used to store it near electric motors. Ozone - think about it.
I use foamboard only for two applications, neither being of CP requirement: (1) title tablets for fine art exhibitions (2) mounting non-CP projects, usually photographs. Why do I bother with ArtCare foam when regular might serve as well? . . . because ArtCare foam is about as close as I can get to a CP foamboard - not because of the core, but because of the outer ArtCare paper and its Zeolite technology.
Do I use Bevel Accents? - yes, I do . . . but I do not class a Bevel Accents job as being a CP project - it is classed as "undefined." Why? - because of the foam.
In my CP jobs, I do not use foamboard for filler, I do not use foamboard for lifting, I do not use foamboard for sink mounting. I use rag or Coroplast.
Why do I use Coroplast? After considering what I understand about polystyrene, the nature of my work, the potential for harm - and, all things being equal, considering Coroplast's polyethylene parentage, I concluded that the potential for harmful breakdown products from Coroplast is far less than with polystyrene. In short, I prefer to be extra-prudent when I am responsible for someone else's property - Coroplast is a safer bet.
Foamboard is a useful and practical product. There are those who would argue that it is perfectly safe for CP framing. There are those who would choose alternatives.
I happen to think that ArtCare is the best foamboard out there - but I choose not to employ it in CP framing.
In the end, the decision is yours.
[ 03-18-2003, 04:51 PM: Message edited by: Orton ]
