Is it necessary?

[Frame Gal]

We are having a minor debate in my store.

We are floating a piece if art on a fabric wrapped board (the fabric wrapped board is an alpha mat). Is it necessary to use acid-free foam board behind the alpha mat? If we use regular foam board will it potentially harm the art in the future?

 

[janetj1968]

All foam outgasses. The exterior on some is acid free. But just being acid free doesn't mean it doesn't outgas. That's why acid-free foam is a conservation product and not a preservation product. Huge difference.

Alphamat has "zeolytes" which helps absorb outgassing.

But if you want a better package, don't use foam at all. Throw on another layer of Alphamat.

 

[Baer Charlton]

ISO has approved the use of foam-core in a framing package.

PPFA PRINT & OPEN Competition Board, recognizes that approval.

Last I heard, the MCPFs don't.

More than a few museums have been using AF-FC as backing for years
in their temporary presentation shows. (less humidity shift to worry about)

Do what your conscience guilds you to do.. .. .. or your pocket book.

 

[05]

Foam cores can made out of many different chemicals, so it is best to know what you are buying.

Be aware that the term 'acid-free' means only that the material in question was without acids when it left the factory. It does not indicate it will not become acidic over time.

 

[preservator]

Backing board

Boards made of a single material, as Coroplast and Cor-X are made of polyporpylene, only, present fewer chemical and phyiscal issues than boards made of both plastic and paper. Foam centered boards can warp, when the paper on one side is more damp than the paper on the other side and they present the issue of styrene emission, if their foam is a polystyrene foam. Another issue that comes up with paper/plastic boards is the fact that they can not be used in making waterproof packages, since moisture will seep in through the paper, if a sealing tape is used. Chemically, these boards, seem fine, especially if they have zeolites added to their facing paper, but phyiscal issues may lead one to prefer a polyprolyene polyflute board.



Hugh

 

[pwalters]

So in summary, I think the pros here are telling you that the "regular foam" option behind your package is the least palatable of the aforementioned methods. Throw some acid free (or like Janet said another sheet of Alpha) behind it and sleep better.

 

[Greg Fremstad]

Is it necesary?

Here are some om my thoughts on AF vs. regular foam boards and barrier products:

1. The cover paper on foam board is not a barrier aginst passage of any chemicals. I believe that the styrene foam center makes a pretty good moisture barrier. Certainly much better than any pourous paper or rag mat board.

2. No thickness of mat board or barrier paper is a barrier against passage of chemicals. Looking through a microscope, rag board (and barrier paper) look like a scotch bright pad. You can blow smoke right through a piece of 4 ply. So... acid or any other chemicals can get right through. And while we're at it... where does the pressure come from to encourage any gasses from passing through ANY materials in a frame? Changes is atmospheric pressure from inside to outside of the frame package? The frame's lungs? (Read: "breathing")?

3. Remember a few years ago when FACTS was doing a survey on foam boards and I asked on the G if anyone had ever seen damage to artwork from ANY foamboard products and nobody had ever seen any? Some old framers remembered an early foam board from the '70s that turned slightly yellow with age but nobody had ever seen any art work that had turned yellow.

4. Do you know what chemicals "outgass" from foam board? I didn't think so. So exactly what are you talking about. None of the blowing agents used to expand the styrene into foam cause any damage to anything.

5. Is the fabric you are using have any sizing? Is it "acid free"? How do you know? Did you test it yourself? What test method exactly?

6. What are you using for an adhesive for your art work? Yeah, I thought so - a pressure sensitive adhesive of some sort.

7. My guess (repeat: GUESS) is that foam board manufactures just apply a thin layer of pourous neutral pH rag paper to regular foam board, without adding any acid, and call it "Acid Free".

8. It is most important to ask the foam board manufcturers if their board meets the PAT (Photographic Activity
Test). The new ISO standard (International Standards Organization) on materials for long term storage of photographic materials, both film and prints, OKs the use of any fomboard that passes this test. Do you know of any other standard setting organization that approves or disapproves the use of any foamboards. PPFA? HA!

9. If asked, do you think that the foam board manufactures will tell you if their "regular' foam board passes the PAT test? I don't think so.

10. Remember, to be acidic or alkalyne the material must be water soluable. There are no plastics or pressure sensitive adhesives that are water soluable so all "Acid free tapes" are "Acid free". Marketing BS. They ARE filled with plasticisors that will migrate out and harm fine art.

All of these statements or questions come from over 10 years of being involved with helping to develop and write the FACTS standards and are just an attempt to encourage well meaning framers to ge a little more education about their "Profession".

 

[preservator]

questions

Greg raises a number of good topics. The PAT is the most sensitive test, we can look to,strip test is an oxidation test and it will not show up all the things comes out of plastics. Anyone who has opened a case of foam-centered board is likely to recall a pungent odor, that of styrene monomer. Does that monomer pose a problem? No one seems to know. "Acid-free" means only that a material had a pH of 7 or above, at the time when it was tested, but that does not mean that such a material can not emit peroxides, or other gaseous pollutants. Fabric that will be used next to works of art should have sizings washed out. Unbleached muslin is safe, as are polyesters and some undyed silks, but dyed fabrics may have mortants that make them chemically active and the darker the dye, the greater the risk. To have a gaseous barrier, one needs a metal or glass layer, or a ceramic impregnated polymer. Zeolites, sacrifical metals, calcium carbonate, and active carbon can take up pollution, but they are filters and not barriers. The only adhesive that is suitable for use with art on paper is cooked starch paste, which is chemically equivalent to the paper, itself.



Hugh

 

[preservator]

sorry, I meant to say:

The PAT is the most sensitive test we can look to. It is an oxidation test and it will not show up all the things comes out of plastics.


Hugh

 

[Rebecca]

3. Remember a few years ago when FACTS was doing a survey on foam boards and I asked on the G if anyone had ever seen damage to artwork from ANY foamboard products and nobody had ever seen any? Some old framers remembered an early foam board from the '70s that turned slightly yellow with age but nobody had ever seen any art work that had turned yellow.

I do recall a Grumbler who laid a cut edge of foamboard over a jet print for a number of days, and there was a yellowing problem corresponding to the cut edge. It was sent to the Midwest Art Conservation Center, where a classmate of mine dealt with it. As I recall, the yellowing more or less reversed on its own. I remember speculating that the yellowing was caused by the blowing agent, but at the end of the day it was a who knows kind of thing.

 

[preservator]

What we don't know

Rebecca's example illustrates why safety dictates that the materials used in preservation should be as simple as they can, since it is so difficult to anticipate what will come from any material. Commercial prodcuts can change, at any point along the manufacturing chain, without warning and unknown constitutents can be substuted for those that have been specified, in the past. Safety lies in keeping thing simple and using like with like.


Hugh

 

[Puppyraiser]

"Safety lies in keeping thing simple and using like with like." - Hugh Phibbs

Let us all engrave this above our assembly tables.

 

[Jim Miller]

Safety lies in keeping things simple and using like with like.

This reasoning makes really good sense. In order to keep the "chemical soup" of a framing package as uncomplicated as possible, I guess the ultimate environment of the closed frame might consist of only starch paste adhesive, Japanese paper, unbuffered, uncolored cotton boards, and glass.

However, variations have practical advantages, and insignificant compromises of chemistry may be found in nearly all framing. For example, pigmented colors provide decorative latitude with no preservation penalty in normal ambient conditions. High alpha cellulose boards made from purified pulp are almost as good as cotton and are entirely acceptable for preservation framing, their only drawback being a slightly lessened resistance to deterioration over time. The addition of a high alkaline buffer improves even the best paperboard's resistance to acid, and that additive could be a problem only if the framed items were sensitive to a high-alkaline environment. Non-hygroscopic boards, such as aluminum composite material, acrylic, or fluted polypropylene (aka Coroplast), provide valuable rigidity and resistance to the passage of moisture.

ISO has approved the use of foam-core in a framing package.
PPFA PRINT & OPEN Competition Board, recognizes that approval.
Last I heard, the MCPFs don't.

The MCPF program does not exclude the use of foam boards or any other framing products. The MCPF exam candidate's score goes according to how and where within the framing package the various framing materials are used.

 

[Greg Fremstad]

Is it necessary

ISO has only approved foam board that passes the PAT test - presumably, not all foam board pass this test. (Ask your supplier) And... it is not about framing, specifically its about long term storage containers for photographic film, negatives, and prints.

The other benefit of alpha board over rag board is that alpha board doesn't expand and contract near as much as rag board. A test I instigated several years ago showed that a piece of rag board 29 inches long dried out in the heat/vacuum press and then placed in a plastig bag overnight with a wet sponge expanded 3/16 of an inch. the same test done with alpha board only expanded 1/16 of an inch.

Think about a 30 x 40 mat whose borders are about 3-4 inches wide framed in Scottsdale and shipped to Tampa.

Also think about how much a mat board expands and that wood fillets don't expand. Looks great going out the door....

Please note that our Library of Congress, the Canadian Conservation Institute, and FACTS all state that there is no archival difference between rag and alpha products.

 

[Jim Miller]

Please note that our Library of Congress, the Canadian Conservation Institute, and FACTS all state that there is no archival difference between rag and alpha products.

True that.

One advantage of 100% cotton board is that the fibers are longer than the heavily-processed high alpha cellulose fibers from wood pulp, and therefore more resistant to the molecular chemistry that results in acid formation.

In preservation framing the difference might be something like the difference between being thrown overboard with your hands and feet bound in 1" diameter ropes, versus being bound in steel chains. Either way, the purpose of the bindings would be well served before either of them would fail.

 

[karen fox]

fabric mounting

We are having a minor debate in my store.

We are floating a piece if art on a fabric wrapped board (the fabric wrapped board is an alpha mat). Is it necessary to use acid-free foam board behind the alpha mat? If we use regular foam board will it potentially harm the art in the future?

Yes, regular fc is acidic, and eventually will change the acid balance of your rag board mat. Also fabric is acid neutral, but it has sizing that can damage your art down the road. You should take your fabric home and wash it first. If it's silk, etc; you should use a 4 ply rag mat under the mat, with a 1/4" showing.