Polyprop or Mountboard

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Mr.Framey
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Polyprop or Mountboard

Post by Mr.Framey »

I've heard about people using tinfoil or something like Polyprop behind artwork. I know people typically use mountboard behind artwork when framed, but I'm wondering if something like Polyprop would do just as good a job, if not better? Both are acid free and should protect the artwork, but the Polyprop is also moister proof. Also, overtime mountboard would age and yellow just like paper would, but polyprop would probably be more stable.

I know you could use both, but would the backing board be necessary if you were to use something like Polyprop?
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prospero
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Re: Polyprop or Mountboard

Post by prospero »

I use polyprop film in frames as a moisture barrier, but usually not directly backing the artwork. In a typical glazed
frame I would have glass/ [window mount/art/undermount] /film/MDF. This gives me the advantages of MDF (rigidity/strength)
while isolating it from the goodies. MDF can suck up moisture like a sponge and go moldy. Only in extreme cases,
but people treat pictures very badly sometimes. :roll:
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Mr.Framey
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Re: Polyprop or Mountboard

Post by Mr.Framey »

Thanks for the info. Can I just ask what the job of the undermount would be if you're using the Polyprop? Aren't both for protecting the artwork from the MDF? The harmful stuff in the MDF wont get through the Polyprop would it? Couldn't you just mount the artwork to the front mount, then have the Polyprop behind, then the MDF?
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Tudor Rose
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Re: Polyprop or Mountboard

Post by Tudor Rose »

The undermount is there to support the artwork and for the artwork to be hinged to. It should be made from the same quality or equivalent board as the windowmount so if you are using Conservation or Museum boards then it should not age and yellow.

From the Guild 5 levels of framing anything framed to Commended level or above requires an undermount. At Budget or Minimum level then no undermount is specified. The windowmount and undermount together make up the mount package. From the GCF Study Guide - "The purpose is to provide adequate physical and environmental protection for the artwork/object. The boards should be hinged along one, normally the longest, edge ..."

The hinging is more secure if done to a full and rigid board (ie undermount) than to a windowmount. The undermount is sometimes referred to as the barrier layer as it forms a protective layer between the artwork and the backboard. For framing at Conservation and Museum levels then adding a layer of Melinex or other similar material (ie polyprop) between the undermount and backing board adds further protection from migrating acidity. Polyprop is a great barrier layer - but it is not a support layer.

Hope that helps.
Jo Palmer GCF(APF) Adv
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Re: Polyprop or Mountboard

Post by Not your average framer »

Melinex is not the same as polypropylene. Melinex is a trade name for polyester, as is Mylar. Polyester is routinely used by museum conservators as an appropriate material for conservation uses. You won't find conservation materials suppliers offering polypropylene for conservation and preservation uses, because it is not chemically inert and some ingredients within polypropylene can leach out into materials which are in contact with polypropylene over time depending upon environmental conditions.

This may not matter in many cases, but it is good to maintain the distinction, so that everybody knows what matterials are recognised as chemically inert and therefore fully accepted as appropriate conservation / protection materials. Polypropylene is used by plenty of framers for non-conservation use without any real issues, or problems. Just be aware that this is not an approved conservation material.
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Tudor Rose
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Re: Polyprop or Mountboard

Post by Tudor Rose »

Polypropylene (archival quality) is sold by Conservation suppliers. In some specific cases it is recommended over polyester because it is softer and the edges less sharp. https://www.preservationequipment.com/C ... ook-Strips

We’ve been buying this wrapping film for years to wrap mounted prints etc and the supplier states it meets Conservation standards if you click on the additional info button
https://www.arqadia.co.uk/productdetail ... =999000059

Mylar/Melinex are what we personally use as additional barrier layers, but the correct quality of polypropylene could also be used, which is why my original answer stated Melinex or other similar material (ie polyprop). My apologies if that wasn’t clear.
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Re: Polyprop or Mountboard

Post by Not your average framer »

I'm very surprised at this, I know that there is more than one type of propylene, but this must be a very different fomulation of the polypropylene to normal propylene. Is this a new formulation?
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prospero
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Re: Polyprop or Mountboard

Post by prospero »

I think there is a danger of overthinking this subject. :roll:

I'm talking about using polyprop as a failsafe barrier material. It's 'conservation' properties are irrelevant.
OK, Mylar is arguably more stable and by all means use it instead of polyprop. But for the purpose of providing
a moisture isolation barrier it's a very fine point. :wink:
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Re: Polyprop or Mountboard

Post by Tudor Rose »

Absolutely agree Prospero, and in fact the OP also mentioned foil as a barrier layer and this would work equally well.
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prospero
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Re: Polyprop or Mountboard

Post by prospero »

:D I once had a lady bring one of my frames in for repair. She had suffered a burst pipe and the frame got a drenching. :shock:
There was mold of all colours on the back - green, yellow, purple. :? Thankfully the artwork escaped unmolested.
That's when the plastic barrier fulfilled it's destiny. :clap:
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