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Conservation Framing?

Dave

SPFG, Supreme Picture Framing God
I agree, Bron. I personally do not like glazed canvases. It seems to take away from the tactileness of the painting.

I do understand the use of them in public places, but I would never glaze a painting on canvas in my home.
 

rmehoves

CGF II, Certified Grumble Framer Level 2
Setting aside all the issues and opinions, there could be something very pragmatic at work here. It's very possible that the previous framer was presented with a canvas already stretched on unsealed stretcher bars. If I were in that position, I would give serious thought to just leaving the canvas alone and framing it as well as I could. Removing the canvas and stretching it again add a lot of extra handling, increasing the risk of damage.
Most of these were re-stretched because they were sagging horribly and when I asked why we were not sealing the stretcher bars but the frame (as previously) no one really had an answer, hence the question posed here.

I am a photographer also and I absolutely hate glass over canvas, yes it protects it but it takes away from the aesthetics.
 

Jim Miller

SPFG, Supreme Picture Framing God
So far only only one reason has been offered for not glazing canvas paintings, photos, and textiles: visual aesthetics.

Glazing provides protection. Why is that important and aesthetically OK for watercolors, but not canvas paintings? Does it matter that the important paintings in museums now are glazed? Does it matter that optically coated glazing products are nearly invisible in proper lighting?
 

Dave

SPFG, Supreme Picture Framing God
...

Glazing provides protection. Why is that important and aesthetically OK for watercolors, but not canvas paintings? ...
Because there is no alternative.

...
Does it matter that the important paintings in museums now are glazed? Does it matter that optically coated glazing products are nearly invisible in proper lighting?
Museums have different security requirements than an oil in a home. Also, even though they are nearly invisible under optimal lighting conditions they are not totally invisible and also do restrict some of the visible light spectrum which inhibits viewing, IMHO.

I understand that museum grade glazing offers more protection than varnishing a painting both from air born pollutants & grafitti or other physical damage and provides more UV protection than most varnishes. In addition it helps to squelch rapid environmental fluctuations such as drastic temperature and humidity changes. However, the average environment for art that resides in a non-public place doesn't normally need this extra protection and I feel it inhibits the enjoyment of the art.

Besides, most home environments do not have optimal lighting.
 

Jim Miller

SPFG, Supreme Picture Framing God
Because there is no alternative.
Sure there is -- framing without glazing.

Paper-borne works (including photos) are vulnerable to all sorts of harm from direct exposure. But so are nearly all other artworks; the only difference is the degree of vulnerability.

It's still the same argument. There are several good reasons to glaze a painting, and only only one reason not to -- which is much less valid then it was before optically coated glazing came along.
 

Jeff Rodier

SPFG, Supreme Picture Framing God
Jim, the no glazing of paper option leaves the paper to age at a hugely accelerated rate. Oils can go unglazed for hundreds of years and remain in excellent condition. Exposed paper on the other hand will age in a matter of a couple of years. It is also much easier to return an oil to its original condition in a restoration than paper art. Even unvarnished oils can withstand many hazards that would render paper worthless. A properly varnished oil can withstand most hazards with the exception of punctures. Protecting from punctures requires acrylic and Optium is not for the average oil painting because of price.
 

Bron

SGF, Supreme Grumble Framer
"So far only only one reason has been offered for not glazing canvas paintings"

Jim, I did mention a possible problem, and admitted it was with limited experience, as glazing oils on canvas is still rare, even in museums.

Oils take years to completely dry; it could be a problem. The fact that unglazed o/c have survived for hundreds of years, would indicate, to me, another non-problem needing a solution. OK. :smiley:

Protection from nuts, and incessant flash photography is another issue.
 

team

Grumbler
i think everyone around here just needs to relax a little. it sure is a nice debate, but it's getting a little too dramatic around here.

was the original question even answered yet?
 

Jim Miller

SPFG, Supreme Picture Framing God
Jim, I did mention a possible problem, and admitted it was with limited experience, as glazing oils on canvas is still rare, even in museums.

Oils take years to completely dry; it could be a problem.
Actually, glazing oil paintings is no longer rare in serious art museums. Most of them do it sometimes, and some of them do it quite often.

Older paintings probably will not off-gas unless something has invaded the layers, such as airborne contaminants or chemicals used in previous cleanings.

As retail framers, we are asked to frame a lot more "fresh" oil paintings that have not yet cured and, of course have not yet been varnished. As such, they are more vulnerable than older, varnished paintings.

The off-gassing issue is well known to those who glaze oil paintings, and it is only a minor inconvenience. If/when the painting deposits a film on the glazing, clean the glazing and refit. The film will do no harm to the glazing or the painting.

When we frame a painting with glass or acrylic, we mention the possibility of a deposit on the inside of the glazing, and offer to clean and refit it at no charge as often as necessary. I have cleaned several after a year or so, and only a couple have come back for a second cleaning/refit.

Of course, acrylic paintings dry quickly and will not off-gas. They are seldom coated, and they are nearly impossible to clean in any case, due to the tiny craters over the entire surface that accumulate soil.
 

Dave

SPFG, Supreme Picture Framing God

Bron

SGF, Supreme Grumble Framer
The issue of glazing bothered me, so:

"Hackney, Stephen.
The evolution of a conservation framing policy at Tate.

In book. Museum microclimates: contributions to the Copenhagen conference, 19-23 November 2007. Padfield, Timothy; Borchersen, Karen; and Christensen, Mads Chr., Editors. Nationalmuseet (Denmark) (2007), pp. 229-235, [English w. English summary]. 5 figs. (4 color), 24 refs. [ISBN 978-87-7602-080-4; 87-7602-080-0].

Use ofglazing for protecting paintings has a long history, and this has been developed into a frame microclimate system that has been applied to much of the collection at Tate. The article describes the evolution and rationale for this approach, analyzing the risks addressed and assessing the benefits and shortcomings. Topics covered include: various types of frame; low-reflecting glass; acrylic glazing; analysis of breakage risks; transit/storage frames; backboards; and pollutants within the frame microclimate. The author calls for further study of the last issue to ensure chemical stability.

Abstractors: Author Abstract, ICCROM, and Cynthia Rockwell
AATA No.: 2009-110909"

This is from the Getty, Abstracts of International Conservation Literature. The italics were added by me.
 

Bron

SGF, Supreme Grumble Framer
One other point, then I need to do some actual work. ;)

I find it interesting that it is the Tate glazing all the paintings. Weren't they one of the museums, like the Louvre at the direction of Napoleon, that reframed all of the paintings to a common style, then threw the old frames out? Not sure of my history, but sounds right. Definitely done at the Louvre.

Artistic and cultural atrocity? Oh, so sorry, framing isn't even a "decorative art". What was I thinking? My bad. :soapbox:
 

PaulSF

PFG, Picture Framing God
The Norton-Simon Museum in Pasadena also has glazing on almost all the paintings on display. Barely noticeable.
 

Jim Miller

SPFG, Supreme Picture Framing God
...and pollutants within the frame microclimate. The author calls for further study of the last issue to ensure chemical stability.
This is an issue for any closed frame, and studies will be going on for a long time. Call it progress. The author's caution should not be taken to suggest that frames left wide-open would be better. The micro-climate of preservation framing is here to stay.

Modern preservation framing pays close attention to the chemistry of materials, which are generally much better than they used to be -- more inert composition and less reactive in normal environments.

For example, that's why adhesive chemistry is such a big deal, and why we use alphacellulose dustcover paper now. Migration within the closed up environment of the frame is reduced by such things as (...ready for this?) barriers of glass and metal, such as rabbet-lining tape and Marvelseal. Fluted polypropylene is among the best materials for backing boards. Aluminum composite sheeting is now used in some framing.

Check out the new classes by Hugh Phibbs at the Anaheim PPFA convention, #F11 "Preservation Chemistry" and #F21 "Preservation Physics". I haven't seen them yet, but I'm sure they are about this very topic.

In a museum, where a hundred-year-old artwork may still reside in its original frame, chemistry could be a big consideration in closing it up -- not only in the original materials' composition, but also migration of outside elements during its years of being wide open. New materials would often be better, but not always.

In any case, museums these days will do whatever they can to preserve the original appearance of the framed art, while creating a chemically-acceptable micro-environment. The days of throwing out original frames in favor of new appearances are gone, thankfully.
 

Bron

SGF, Supreme Grumble Framer
Jim,

Sadly, you're probably right about the way of preservation framing, as it's another barrier between the art and the viewer, however minor, and thats a topic for another day. I'm still cynical enough to wonder at doing something with acknowledged, unknown consequences. Probably the positives outweigh the potential risks, at least in a high traffic, museum environment.

More of my cynicism; wasn't there a recent controversy at MOMA, NYC, with a reframing of some of the early modernists to a "standardized" frame. My brief search couldn't find it, and I'm supposed to be working, not on the interwebs; I'll look more later.

This has been an interesting thread, and I'll paraphrase Brahms, if I've offended some, but not all, I'll try harder next time.

;)
 

Framing:

In Corner
So if oil paintings are ok to go unglazed and that no real damage is done which I doubt.

Should the same conditions not prevail to indoor painted surfaces in our homes!!!!!, yet most people that I know will repaint their homes every 5 to 10 years due to the deterioration of the painted surface in most cases.

Glazing technology is a long way ahead these days in comparison to the days when oil paintings had to be varnished to protect them, in those day if you put the sort of glass available on an oil painting it would have been virtually impossible to view it, the glass was so imperfect in comparison to the glazing options available today.

I find is amazing that some framers will go to great extremes to make a box frame with top of the range glazing for a gun yet will refuse to put glazing on an oil painting, strange old world.
 

Dave

SPFG, Supreme Picture Framing God
:faintthud:

I would never refuse to put glazing on canvas borne art. It is just a matter of personal preference.

Why is this so difficult to understand?

As others here have stated, glazing a painting will not necessarily ensure that it will last longer than a properly stretched, framed and varnished oil painting.
 

Jeff Rodier

SPFG, Supreme Picture Framing God
Glazing technology is a long way ahead these days in comparison to the days when oil paintings had to be varnished to protect them, in those day if you put the sort of glass available on an oil painting it would have been virtually impossible to view it, the glass was so imperfect in comparison to the glazing options available today.

I find is amazing that some framers will go to great extremes to make a box frame with top of the range glazing for a gun yet will refuse to put glazing on an oil painting, strange old world.
Oil paintings still need to be varnished whether glazed or not.

I find it amazing that framers will get so worked up about a piece that the artist isn't serious enough to varnish. In the old days we varnished paintings for the customers. We declare every oil that walks through the door as priceless but treat them as if they were worthless. Go figure.
 

Rebecca

SGF, Supreme Grumble Framer
"Howsomeever, this from Getty Conservation.

There was a big stink a while ago amongst photographers; their "archival" storage sleeves seemed to be melting into the photos. Oh, no, how could this be? "

Darn, I goofed up the quote function again, but the above is from an earlier Bron post on this thread....

Not sure what the Getty link is apropos of re materials used in conservation; it is about the deterioration of plastic materials in museum and other collections. Not a new topic (it started making big conservation news in the 80's and 90's) though certainly interesting for the caretakers.

I have not heard of true archival quality storage sleeves ( Mylar or polypropylene or PAT paper enclosures) melting onto photographs - perhaps you are thinking of plasticised PVC sleeves where the plasticiser can exude out? There are plastics and there are plastics and plasticised PVC has never been on the conservation "approved" list...

This thread has wandered around the mulberry bush quite a bit; if anyone wants to discuss specific questions about specific materials or practices it would be easier to follow, and more useful to readers, if new threads were started and titled with the topic.
 

Rebecca

SGF, Supreme Grumble Framer
I find it interesting that it is the Tate glazing all the paintings. Weren't they one of the museums, like the Louvre at the direction of Napoleon, that reframed all of the paintings to a common style, then threw the old frames out? Not sure of my history, but sounds right. Definitely done at the Louvre.
I don't quite follow the logical trend in all of this - Napoleon made all sorts of changes, including redesigning Paris, lots of medieval streets and buildings thrown out there too! I wouldn't catagorize the decision to glaze or not to glaze with the decision to retain or throw out original frames, nor are these decisions made by the same departments.

Maybe the stream of consciousness style of this thread is the new in thing; it is too difficult and time consuming for me to follow or contribute meaningfully to, but if any of these topics/subtopics really are of interest to anyone, please start a new focused thread and I would be happy to contribute in any way I can.
 

Bron

SGF, Supreme Grumble Framer
Rebecca,

My point and what all this wandering around seems to be about, is that sealing stretchers and frame rabbets solve a problem that isn't a problem, so, why solve it? Nobody has refuted it as being a non problem, though I don't dismiss the possibilty of contribution of acid from the wood adding to fabric coming apart at the arrises.

The point of the plastics idea, is that when they were introduced, we were told they were safe. Now we know. We are being told that many modern conservation approved materials are safe, but they have only been in use for 30-40 years. My point is, we don't know. Solving non-problems with unproven materials seems at best risky. One of the points in the plastics article is the problems arise quickly, and we are not always sure of what is going on exactly.

The segue to glazing and sealing canvases seemed pretty natural, and my point there is that outside of special museum conditions, and considering that it may add problems, why muck with a system that has worked pretty well for around 500 years. Does connect to the original question.

The reference to reframing to a uniform style, was off topic. I apologize.

:bdh:

Well, if you don't get the point now, I must have smileys companion's communication skills.
 

Jim Miller

SPFG, Supreme Picture Framing God
...glazing a painting will not necessarily ensure that it will last longer than a properly stretched, framed and varnished oil painting.
Not true. Properly framing a painting with glazing and solid backing will ensure longer useful life. That is true in any environment, whether protected, normal, or hostile.

Any painting displayed in an open frame will need to be cleaned and repaired occasionally, and it would be more vulnerable to harmful environmental conditions and accidental damage.

There is no doubt of the value in keeping a painting free of soiling, airborne oils/solvents/other chemical contaminants, abrasions, punctures, flexing from sound waves, damage from light.

To wit: The only paintings that have survived a hundred years are the lucky ones. Many more have been destroyed by neglect and accidents, which might have been avoided in a properly-closed frame constructed by modern preservation framing standards.

Unfortunately, modern preservation framing standards did not exist a hundred years ago. Fortunately, they do now.
 

Jim Miller

SPFG, Supreme Picture Framing God
Sadly, you're probably right about the way of preservation framing, as it's another barrier between the art and the viewer, however minor...
Yes, it is a minor barrier, and well justified by the known benefits.

I'm still cynical enough to wonder at doing something with acknowledged, unknown consequences. Probably the positives outweigh the potential risks, at least in a high traffic, museum environment.
Like Rebecca, I'm having some difficulty following this thread.

If you are still talking about closing a painting into a frame with glazing and solid backing, what could be the "unknown consequences" in that? You would not hesitate to close the windows and doors of your home for fear of "unknown consequences", so why would you have such concerns about a painting?

If you are talking about sealing stretchers with a gas-impermeable barrier of metal, such as foil tape, the materials and methods have been very well-vetted by some of the best conservators in the world. Again, why would you be concerned about "unknown consequences" when the known chemistry and the possible benefits are so well established?

More of my cynicism; wasn't there a recent controversy at MOMA, NYC, with a reframing of some of the early modernists to a "standardized" frame.
Now you refer to the aesthetic and practical considerations in the framing practices of one museum. If we are changing the topic again, I guess most of us would agree that it is important to keep the appearance of a culturally-significant artwork as close to original as possible. Preservation framing assists that objective by preventing harm, and is not a deterrent to aesthetic value.

Thanks for speaking your mind and offering such thought-provoking questions for discussion.
 

Bron

SGF, Supreme Grumble Framer
Jim,

The "unknown" is the sealed environment, which is nothing like closing the windows in your house. Which, since you brought it up, is a problem in some of the new, super efficient houses.

Outside of a museum, which may have special concerns, glazing and sealing canvas paintings is putting an unproven system, 30-40 years, on a proven system, some 500 years. Yes, there are problems with canvas paintings, but for artists, the benefits out weighed the loss of durability over tempera on panel. (There are examples of glazed paintings from the 19th. c., but they weren't sealed in the way current practice does.)

Nobody has presented any evidence of the benefit, in a home, for a glazed and sealed canvas, whereas I have pointed to concerns from the conservation field about the sealed environment. I have also mentioned my own experience, admittedly limited.

Saying I'm changing the thread by some asides about museum practice, past and present, indicates to me a rather simple acceptance of whatever the "gods" I've mentioned before, decree. Museum practice is actually linked very well to this thread, good and bad museum practice.

As Dave said: :faintthud:
 

Jim Miller

SPFG, Supreme Picture Framing God
...Nobody has presented any evidence of the benefit, in a home, for a glazed and sealed canvas...
Actually, they have. The benefits you question and the concerns you mention -- and more -- have all been discussed among conservators and museum professionals. To their credit, they continue to question and discuss the methods and materials of framing, as well as environmental norms and extremes.

Few conservators are here, however. Getting acquainted with a number of them is a good idea. They don't always agree, but their arguments are thought-provoking and well reasoned.

Also, if you register for the Conservation DistList (Conservation Online), join the American Institute of Conservation (AIC) and the Canadian Conservation Institute (CCI), you will have access to enough information to better understand the hazards of open display and the benefits of a closed frame. It isn't necessary to be a conservator in order to appreciate the differences.
 

Bron

SGF, Supreme Grumble Framer
:bdh:

Some clarity on my point: We have a 500 year old system, with known problems, and known solutions. Sealing stretchers and rabbets is, until recently, so rare as to be an oddity. Nobody can point to actual evidence that unsealed is a problem or adds to other problems in a significant way.

This segued into a discussion of glazing and sealing canvas paintings, which is a system designed to use a removable varnish as the protection. Not glazing.

Now come those with 30-40 year old materials and processes, that aesthetically alter the work of art from it's creators intent, say it is for the best, and I should not question this? Frankly, this is a cultural outrage, akin to the removal of genitalia from statuary, and the religious defacement of humans. :fire: To say nothing about the 30-40 years not being enough time to prove anything, against a 500 year system that works, as is?????

Personally, I would rather see the art as intended; museums should hire more guards, accept some risk, and enforce the rules. The Mona Lisa is unviewable, as despite the no flash rule, there are at any moment dozens of flashes going off glaring from the thick glazing. As far as I, or most of us are concerned, it's lost already.

Careful, I'll start ranting. ;)

I think I'll go look for the kitteh thread.
 

Bron

SGF, Supreme Grumble Framer
Jim,

We must have crossed posts.

I think at this point we should agree to disagree. Modern conservation practice, that is willing and ready to alter the aesthetic experience for a supposed long term benefit, is, my opinion, wrong. Hubris. Even though there might be benefits, the history is an unresolvable issue for 30-40 years more, at least; aesthetics, a huge issue.

As an artist, my egg tempera paintings are framed as I think they should be, un glazed, and even unvarnished. That is MY INTENT. Including the fact that it might be ephemeral.
 

Baer Charlton

SPFG, Supreme Picture Framing God
I couldn't agree with Bron more.

I have stood in front of the six inches of green glass set into a steel and concrete bunker that you are expected to look into and see a painting that is reported to be valuable. Truthfully, I would never swear in court that I ever saw the Mona Lisa. It could have been a flat screen projection (albeit a poor quality one), or a ColorPlak for all the depth or dimension I could perceive.

Holding this experience against standing with my face about a foot away from Botachellei's Venus and experiencing the rotting and corroding of the gold on the frame, but the canvas seeming in good shape despite the wafting waves of rotting putrid sewage air rising from the river below and allowed to fill the museum through the hundreds of open windows and giant doors. The rust and corrosion cakes in the hinging attesting to the generations of "open window" policy.

The Louvre, Rijke's, Prado and others have invest tens of millions of dollars to control the humidity and temperature in the galleries, but still understand that the air exchange of 6-8 times a day is critical to the health of the building, people and art.... and yet we sit here debating the quasi hermetic sealing of paintings that have survived just fine for 500 years.

I think a sliver of honesty may be in order about the glazing in museums. Yes, it has anti-reflective coating, but I have not heard any definitive documents as to UV blocking beyond that of regular shatter proof laminated glazing. And lets be honest here... that is the bottom line on the glazing.... I just looks less obtrusive then encasing the art and frame in an acrylic box like they did in the 1970s. Just damage control, not preservation against pollution and UV.

As for sealing wood..... we already have seen and heard that the oxidation majorly occurs along the unsealed cracks between the cedar boards used for backing, than by or from the contents in the wood themselves.
 

Rebecca

SGF, Supreme Grumble Framer
Well of course there is no one answer, there are lots of variables. a particular piece that has done well for 500 yrs in one environment would not do well in another environment.

I think each caretaker is trying to do the best they can given the information and conditions they have.

If anyone wants to take a single query or thought and explore it fully that makes sense to me, but to say "this happened here, so xyz there is unexplained or incorrect" is inefficient and can lead to the wrong conclusions.

For example, as Hugh said, the long grain of wood is not generally a problem in strainers/stretchers (kind of wood, quality of wood, and environment would all be contributing factors though).

The cedar or other wood boards Baer is talking about certainly can cause "burning" to the paper behind them, most of us have seen the patterns they can create (in certain environments - humid springs to mind) on paper.

The cracks between the boards allow air pollutants in; that is a different kind of damage, not necessairly related to the wood. That is an argument for sealed framing, though our indoor air is cleaner now than when we all burned coal or had open fireplaces or oil furnaces.

What I am trying to say is, there is no absolute right or wrong, there are questions to be asked and contributing factors explored. But mixing it all up leads to confusion and no meaningful answers, just tits for tats. IMO
 

Jim Miller

SPFG, Supreme Picture Framing God
Yes, it seems unwise to make absolute conclusions about these issues, since exceptions to every general rule are everywhere.

Here is an example where direct contact with the surface grain of wood, as well as the end grain, caused damage. This photo shows the back of a photograph on the left, and it wood backing board on the right.

Other than some foxing on the face of this hundred-year-old-or-so framed photograph, probably associated with the glass pressed against it, there was no evidence of a hostile environment.

No problem?
 

Attachments

Baer Charlton

SPFG, Supreme Picture Framing God
Thank you Jim, I was looking for a good photo example for just this.



The areas mark with"

"1" are examples of end grain and resulting damage. One of the major problems with using "knotty" boards is that the grain around a knot becomes transverse in most cases. For those who use hand planes, it is this region that causes the most problems; not the knots.

"2" is a great case of "Oxidation due to an air pocket". In the area on the right, you can make out the original sawyer's marks that were not planed smooth. This was because the board in that patch was thinner than the rest. This board was "machine" planed, as apposed to an older piece that would have been hand planed. That thinner area (lower than the surrounding area) created an air pocket. If it had been in the middle of the board, it probably would have been sealed by the surrounding area; but as it was at the end, the resulting pocket air suffered from the end grain off gassing, as well as the external air flow that is indicated by:

"3" is resulting of air flow more than end-grain off gassing. The burning is more severe in the middle because of Oxidation from the intrusion of outside air. The Left and Right perimeters are more severe burns because of the additive of the toluene off gassed from the ends of the boards.
The middle burns severity are a result of the "pumping" effect that occurs from a change in the room pressure from opening doors. [this is easily observed in a very steamy bathroom by rapidly opening and closing the door to clear the steam] The "pump" draws the new air in through the cracks, and the longitudinal crack is the center of the pump and receives the most.
The left side of the document (right of the boards) show more burn being drawn into the center and would indicate a "looser" fit of the nails holding in the backing; making less of a seal. [The longitudinal burn is darker in that area as well (when compared to the other end).

:D
ain't forensics great? :D thanks again for such a great example with the full range of exposures.
 

shayla

WOW Framer
So, this is a question that seems okay to ask here.

It's a good idea to leave air space between the
paper art and glazing in a frame. But this week,
there have been comments of interest to me
on the G. One is over in Kirstie's thread where
those prints were kept in a plastic sleeve in a
drawer, and the one that was behind, sticking out,
has some weird discoloration. Someone said that
maybe the air space allowed for it to interact with
heat or humidity changes. Then on this thread,
Baer just mentioned (post #83, comment 2)
about how an air pocket between the wood and
art could allow for a more volatile reaction (my
paraphrase) to occur.

It's making me think that sometimes having an
airspace can create more potential for damage
to occur. I wonder if a piece was framed with
acrylic right against it, or with air space, which
would look better a long time from now. I know
it's good to have that space, but these comments
are sure piquing my curiosity.
 

Bron

SGF, Supreme Grumble Framer
Hi Shayla, Picture Framing Goddess,

I think the picture above is a worse case example, using materials best suited for cooking salmon, yum.

I'll let my betters, more conversant with glazing say more.

So, Hi! ;)
 

shayla

WOW Framer
Hi, backatcha. :icon21:
 

Baer Charlton

SPFG, Supreme Picture Framing God
We see damage also in the front Shayla. Look at the burn marks that radiate from the cut bevel of an old mat.... yet, directly under that nasty bedrock of burning acid.... is a perfectly unburned paper on the artwork.

So the question at that point is acid gas + air = burn or is it acid gas + light = burn?...... but then you see that pocket that was burning gently (we have no idea for how long but we can guess over 80 years) and the theory that pops into my head is "YES".

Ok, so that was a little SA response.

My guess would be:

  • Acid+air=burn
  • Acid+air+light=more burn.
but we also know that a glossy photo gel smashed up against a smooth glass (and add time and humidity in the cycle) results in a glued on photo.
but I'm not as sure of the acrylic.

Is that clear enough? :kaffeetrinker_2:
 

shayla

WOW Framer
Thanks for taking time to answer.
It helps me make more sense of it.

You know, you really shouldn't be
drinking coffee so late at night. :popc:
 

Jim Miller

SPFG, Supreme Picture Framing God
Lovely pictures, though in a discussion about stretched fabric paintings, I'm not sure of the relevance?
I'll consider myself suitably razzed, Bron. :icon11:

The discussion was about the reasons to create (or not) a barrier between raw wood and the canvas, no?

Well, there's an example of what raw wood can do, and it happens often enough that most framers get to see this sort of damage occasionally.
 

Jim Miller

SPFG, Supreme Picture Framing God
It's making me think that sometimes having an airspace can create more potential for damage
to occur.
The air space is beneficial. If nastygas permeates the air space, that would be harmful. As Baer pointed out, light, heat, or moisture could trigger, or at least amplify, the chemical reactions.
 
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