How does metal leafed wood answer archival requirements?

Whynot

SGF, Supreme Grumble Framer
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As I gathered, wood has a pinch of an acidic PH and its fumes may damage the artwork over time.
Would you please help me answer these two questions below?
1. Is metal leafed wood archival or not with respect to the art work? In this case the wood is covered by succesive layers of gesso, clay, shellac, oil size, metal leaf and varnish.
2. How is the art work usually protected against potential damage from being framed in wooden frames?
 
Cornell,

FACTS stipulates that the only acceptable barrier for acid migration is glass and metal... so:

Leaf the rabit and you're good as gold.

Personally I have yet to find a chunk of Limewood, or Bass that went below a 6.5 which is less than the swing on any given day in the air of Portland, much less Los Angeles.

I can't see any reason why a fine aluminum leaf wouldn't barrier enough also. Of course Lineco barrier tape is probably cheaper and quicker... :D
 
Baer Please inform this wood ignorant, used to be framer. But is the PH of the wood the only thing that needs isolating from the art work inorder to meet C/P standards? I seem to remember a problem with most wood having Lignun and tanin qualities as welll as a few other things they can exude even if they are PH safe and will remain that way for as long as the frame last.

However The propeties of metal leafing when propely applied does bring up some interesting possibilities if the other eliments of leafing are not a contanimnent in themsleves. Maybe Hugh or Rebecca or one of ourother resident Conservators would care to give us an educated second opinion about if gilding can be a safe barrier. But I would suspect that there may be some cheaper and less time consummeing don't you think?
BUDDY
 
Originally posted by Baer Charlton:
Of course Lineco barrier tape is probably cheaper and quicker... :D
ah, Buddy? Will this do?
popc.gif
 
If Jan Van Eyck's paintings in oil on wooden panels have survived for 600 years, aren't we being a little over-cautious in worrying about off-gassing from an exposed wooden frame? Many works of art nowadays, it seems to me, are made without following time-honored good practice, made worse by using modern fugitive materials. Many artworks will fall apart long before the frame does anything to it, despite a framer's best efforts.

Is there a corresponding self critical series of threads on artists' forums where they exhort each other to use archival materials to preserve their work for hundreds of years? I doubt it.

Paul Hardy
 
Originally posted by Paul Hardy:

Is there a corresponding self critical series of threads on artists' forums where they exhort each other to use archival materials to preserve their work for hundreds of years? I doubt it.
Oh yes there are ;) and they all originate from the other side of the pond.
 
Wood does produce peroxides and acids, but side
grain is much less productive than end grain. If
one takes off an old pine backing, the knot holes
will cause much more dramatic stains than the
rest of the board. Paper items are at risk from
wood staining, only if they are close to it. A
window mat that is 1/2" to 1" larger than the sheet should keep the edges of the sheet away from
the staining zone. If the rabbet is covered with
metal leaf or tape, staining potential is greatly
reduced. Anodized aluminum or karat gold are best,
since brass and raw aluminum can cause oxidization
stains on paper that is in contact with them, but
again, that staining will only happen if the paper
is up against the metal. The graduated staining we
see at the edges of old mats may be caused by atmospheric pollution, more than it is by the wood
of the frame.


Hugh
 
Thanks Hugh!
You say it wood garin emits PEROXIDES as well as Acids are there any other contaminents that while being a lessor problem still need addressing?

You also said that"If the rabbet is covered with
metal leaf or tape, staining potential is greatly
reduced. " dose this mean that while they are very helpful they still don't stop all contaiminateing propeties and which is the better/best agent to stop any wood grain problems.

I say this since you have also mentioned that certain brass and raw aluminum metal bariers seem to add to the concerns such as the possibility of stains of oxidation.

I don't really get involved with true C/P work but I have noted a trend to be concerned with the PH of a problem while their are many other contaimenents that may cause harm, even some of the bariers we employ to stop some of the others.
BUDDY
 
This has always been a bit confusing to me also, Hugh, and I thank you for giving Buddy a straight answer to his original question. Whenever we talk about archival protection of this and that it seems like there is hardly ever any mention of framed original oils or works of art on composition board or wood. Some of these artifacts have endured for many hundreds of years and even those on the newer products like masonite or composition board seem to be no worse for wear.

Is this due to the application of gesso or some other type of priming compound to the raw surface of the artwork? I have never been able to see any connection with how a painting is created and what it is housed in for so many years and how many of these works of art can survive for so many years with little or no apparent damage other than drying out of the canvas (which may contribute to the cracking of the paint surface) and the buildup of dirt and grease and the darkening of the varnish on the artwork.

Most of the original canvasses are not protected from the raw wood in the rabbet of a frame by anything save maybe some oil paint that may have overlapped the wrap when stretching the artwork. And most all of them are stretched on raw wood stretcher bars or strainer materials which offer direct contact between the bare surface of the back of the canvas and the raw surface of the wood stretcher bars. If we have so many destructive characters to deal with in raw uncoated wood surfaces, how are many of these canvases surviving for such a long period of time?? I know that this isn't happening to ALL of the old works of art as I have torn down some old canvases and seen the effects of age, tension on the canvas, and close proximity to the wood surfaces. But there are so many that HAVE survived which begs the question of whether we are making an issue out of something that may not BE that big an issue??

(I am simply playing devil's advocate here, folks, not espousing a new philosophy on framing. There just may be some learning to be had in this discussion.)

Never having inspected an Old World masters painting, I am curious as to whether those artists took pains to coat the wood surfaces of stretchers and frames that came in direct contact with their works of art? Was this a concern for them? What is done with one of these pieces when a group of conservators tears one down and does restoration work on it? Are these concerns taken into consideration by the conservators??

OK, I'll quit for now but these are legitimate things to consider when handling original works of art be they ancient or new. And the more we understand about their characteristics, the better framers we can become.

Framerguy
 
Here are some comments from a previous discussion on the subject regarding a question I had pertaining to my own work. ihegrumbe
 
Framerguy has raised some great issues. Antique
wood panels suffer from spliting and insect infestation, but they do not destroy themselves, or the egg tempera on them. Wood is amazingly tough and it can survive for thousands of years, even at the bottom of the Black Sea, which is quite acidic. Our focus on things like "acid burning" may mislead us to the impression that wood is a destructive materal. We can say that its peroxides will stain paper, but wher we see old paper and board weaken, it may be caused by the lignin it contains, but it may also be due to alum rosin in the pulp.
Stretched canvas may be affected by the wood of the stretcher, but it is certainly degraded by air pollution. We know that canvases that had backing boards show much less damage than those that do not and keeping the pollution from the canvas makes sense.
Panel paintings, either wood planks or pressed wood, are phyiscally vulnerable, but chemically (absent bad additives in the pressed wood) they have performed very well over time.

Hugh
 
Thanks Hugh and TOM ;
Ya'll have brought out exactlly what i was searching for. That being that not unlike our mat MONTRA "IT's ACID FREE" and it seems to me that it doesn't mean anymore with the wood in frame construction then it does in Mats.

By this i mean that being "ACID FREE " or even PH neutral is a good feature but there are many more factors to be considered some that maynot even occur right away.Some which may resultfrom things we do to prevent the acid propeties of the wood from coming in contact with the work ( e,g, possible oxidation of the metal barriers)

It just raised my eyebrow when I saw the concern about the PH of the wood without considering Lignin .peroxide, out gassing and other delayed chemical reactions.

It would seem to me that some examples can be found that singularly seem to contradict all precautions .While Knowledge and experience will dictate that this is an isolated case of good forune ,and baseing all other work on it could prove to be disatorus.

At least that is what I remember from my classes not that I have ANY personal experience or Credntials.( I too Tom am playing Devil's Advocate hereand previously) and I hope I haven't mislead anyone. That is why I defer to the most knowledgable people I know the CONSERVATORS like HUGH and REBECCA and others.
BUDDY
 
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