Question Stretched Canvas... to paper seal or NOT?

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MitchelC

MitchelC

MGF, Master Grumble Framer
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Sep 19, 2010
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Charleston, SC
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Custom Framing
When i frame stretched canvases, i always ask the customer if they want a "paper seal" covering the back (and I explain why it should). 50% say YES / 50% say ABSOLUTELY NOT and explain why: "The back should NEVER be sealed because it should be able to b-r-e-a-t-h-e." The other 50% that say "YES" because they understand the problems that could occur if it is NOT paper sealed.

The problem is a "dust collection" between the stretcher bar and the canvas... mainly on the bottom. I have seen damaged canvases because of this in the past. In my opinion, paper backing still allows the canvas to breathe.

One canvas I re-framed DID have a paper seal in the back, but, she (elderly lady) must have punched a million holes :nuts: the size of an ice pick in it. This resulted in dust build-up at the bottom... damaging about 3/4" of the canvas. I asked her why she did this and was told by her "art teacher" it MUST breathe.

Do you seal the back of stretched canvases?

Thanks for your opinion. :thumbsup:
 
MitchelC said:
When i frame stretched canvases, i always ask the customer if they want a "paper seal" covering the back (and I explain why it should).
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Why should your customer make the decision? You are the professional, dispensing professional advice, correct? Does your doctor ask you what kind of cholesterol medicine he should prescribe for you?

MitchelC said:
50% say YES / 50% say ABSOLUTELY NOT and explain why: "The back should NEVER be sealed because it should be able to b-r-e-a-t-h-e."
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[video=youtube;KAs7SMVaJ4o]http://www.youtube.com/watch?v=KAs7SMVaJ4o[/video]

Yes, please, for the love all that is good and holy in the world, yes, do use a dustcover. And please, please, use a rigid backing. Actually, just using a rigid cover will prevent 90% of the dust and insect intrusion, the dust cover keeps out the rest and just looks so much better.

And come on, it's not like we're creating a hermetically sealed package. Even if a dust cover did benefit from air flow (WHICH IT DOESN'T!) air will still be able to circulate in and out of the frame, albeit at a much slower rate. And that's a good thing.
 
shopmonkey said:
Sealed by dustcover= ok
Sealed by polyflute+dustcover=better
Sealed by polyflute+dustcover+glazing= best
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Actually polyflute lined with a 4 ply buffering material like rag or better yet Artcare Rag (Canadian standards) + dustcover is even better.

Cutting holes in the dustcover is even worse because it allows for areas of localized humidity and temperature on the back of the canvas.

An excellent resource is the PPFA Guidelines for Framing Works of Art on Canvas and

Paul McFarland's book of Framing Works of Art on Canvas. http://www.amazon.com/Framing-Works-Canvas-Paul-MacFarland/dp/0966318951
 
We have been all over this topic several times in previous threads. Here's one. And here's another, which covers several related topics.

There are many reasons to use a solid backing and glazing when framing a canvas. There is only one reason to leave it unprotected.
 
prospero said:
But if you have the canvas open at the back you can at least see what's going on.
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Yes, you can get a lovely view of the soiling and damage as it happens.

prospero said:
And you can take the picture off the wall and give the back a periodic vacuuming.
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Or you could use a rigid backing and dust cover, keeping it clean to begin with.

Let's not get too hung up on dust; it's just one source of potential damage. Consider mechanical damage such as dents and punctures, long-term damage from vibrations and rapid swings in temperature and humidty along with it. A rigid cover will help deal with this issues.

I'm really not sure why this is still an issue. We have the PPFA Guidelines, Paul McFarland's book, the CCI, and Hugh Phibbs, among other sources, all of which recommend the use of a rigid cover and provisions to keep dust and insects out.

The only arguments against it amount to "I've always done it that way" or "I was taught to do it that way by (fill in the blank)."
 
One cannot get between the lower bar and the canvas to vacuum it out. Dust and debris there combined with moisture is the perfect breeding ground for mold.

I just don't get the resistance to the new standard. As time moves on and conservators and other experts determine that what was accepted as "generally acceptable framing practice" is not appropriate, and/or as new and better materials are developed, standards are modified and changed. That is why the CPF Recertification is so important. Standards and materials change and one needs to keep abreast of the latest standards.

I do recall that at one time the "state of the art" was to cut holes in the kraft backing and to be really cool, line them with window screening or cheesecloth to keep out insects. As conservators received the paintings for treatment (for other causes) they noticed that the areas with the holes had different reactions to those where the holes weren't. They call this areas of localized humidity changes and advocated against the practice of cutting holes in backing (rigid or paper). Conservators also have found that the majority of damage to paintings was happening from the back (especially if they were backed with paper only) as people had a false sense of secutiry and leaned the paintings against something that punctured or indented the back

Current standards for framing canvas state that canvas art should have a rigid backing. Canadian standards state that the backing should also have a buffer like rag in addition to fluted poly.

When I started framing, someone felt that using 3M Micropore tape was appropriate as a hinging media as it worked well on skin. Today we know better, but I am confident that there are back issues of DECOR that promote this concept. Lining corrugated cardboard with rag as a barrier for backing was also common practice, but we now know that matboard is not an acceptable barrier and it is no longer acceptable.

Time and technology changes and so do the framing standards surrounding the practice.
 
RoboFramer said:
5. It carries mold spores :thumbsup:
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We do a significant amount of installation in hospitals and all of my crew has to be double TB tested and MMR certified (measles, mumps and rubella). We also have to take 6+ hours of dustbuster training to receive a dustbuster certificate that must be attached/displayed on our laminated name badges.

We have been spot checked in hospital corridors and asked to produce the certificate.

A good deal of time in the class is spent dealing with Aspergillus, which is a serious concern in US Hospitals.

Aspergillus (IPA: ˌæspəˈdʒɪləs) is a genus consisting of several hundred mold species found in various climates worldwide.

Aspergillosis is the group of diseases caused by Aspergillus. The most common subtype among paranasal sinus infections associated with aspergillosis is Aspergillus fumigatus. The symptoms include fever, cough, chest pain or breathlessness, which also occur in many other illnesses so diagnosis can be difficult. Usually, only patients with already weakened immune systems or who suffer other lung conditions are susceptible.

In humans, the major forms of disease are:

* Allergic bronchopulmonary aspergillosis or ABPA, which affects patients with respiratory diseases like asthma, cystic fibrosis, and sinusitis).
* Acute invasive aspergillosis, a form that grows into surrounding tissue, more common in those with weakened immune systems such as AIDS or chemotherapy patients.
* Disseminated invasive aspergillosis, an infection spread widely through the body.
* Aspergilloma, a "fungus ball" that can form within cavities such as the lung

Aspergillosis of the air passages is also frequently reported in birds, and certain species of Aspergillus have been known to infect insects.
 
Rob, aren't you in the air? Those first class seats must have lots of high tech connections:D Check the plane for Aspergillosis. Just kidding. Good points as always. I think I need to write a newsletter item on the backing of canvas. Perhaps a series on myth busting.
 
Hi ShyMama07, and welcome to the G.
Can newsprint be used for a dust cover? Technically, yes. Practically, no.
Newsprint is relatively thin and weak. It also has a high lignin (wood protein) content and ages quickly in the presence of oxygen. That process produces acidic gasses which can have a deleterious effect on any organic material they are near, the cotton/linen canvas of a painting for example.
I suppose it would be better than nothing, but not by much.
Generally speaking, craft paper (brown or black) is the basic dust cover material, though it has its drawbacks. Better would be the blue-grey paper available from Lineco that is free of wood protein.
As discussed above, best treatments involve a rigid physical barrier and a dust cover.
 
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