What to use to cover backs?

[nickbatz]

I make floater frames for my original prints the way you see here: I get them dry mounted on "archival" foam by a frame shop and cut with a reverse bevel, then I glue that to 3/8" ply strips across the inside of the frames.

The reason I use roughly 1' strips rather than covering the entire back - other than that it works just as well - is a deeply philosophical artistic choice: I can't fit a full 4'x8' sheet of ply in my car, but I can fit 2'x4' strips.

My question: if I wanted to cover the backs of the pictures with something inexpensive just to make it look better - some kind of paper or cardboard would be fine - what would you suggest?

TIA

This is the back of one of them, of course:

 

[nickbatz]

I guess I should add that the two cross pieces are made from what I cut out of the front of the wood to make the floater frame. The top cross piece is 5" above the center on all my pictures, so all the gallery owner had to do was project a level laser line and tap in a couple of nails, and all the pictures' centers were even.

And in case it's not obvious, the other piece is just to balance the one holding the picture up.

 

[nickbatz]

I've been searching, and I think it's just backing paper that I need. It won't really do anything, though, and I'd have to remove those cross pieces on a lot of pictures to put it on. Also, I haven't seen any that's wide enough for the big prints (the max is 36", and some of mine are 44" wide).

Maybe I should just leave well enough alone...

 

[Prospero]

Sometimes the covering of the backs is purely cosmetic. If the fronts are unglazed
then this is the only reason for doing it. Your backs looks presentable enough without it.

I would tend to mount the prints on something more substantial than foamcore
and not paper the backs.

 

[nickbatz]

Sometimes the covering of the backs is purely cosmetic. If the fronts are unglazed
then this is the only reason for doing it. Your backs looks presentable enough without it.

I would tend to mount the prints on something more substantial than foamcore
and not paper the backs.

Thanks for the first paragraph. I can't say the backs bother me in the least, but I want to make sure there's nothing to bother prospective galleries I want to show my art.

The second paragraph, well, the foam is glued to ply, so it's supported and I can't imagine how it would go anywhere. It's the most "archival" (small a) material anyone could find, and they use... I forget the letters, but the adhesive is also blessed by rabbis. It's not Gatorboard, by the way.

There is some aluminum stuff someone recommended, and I looked into that, but it seemed like a lot of bother and expense without any obvious benefit.

What I am looking into is gluing the prints to plywood (coated with gesso to stop outgassing). It would be great if I could avoid having to go the frame shop to have them dry-mounted - not just because of the expense, but because of the time driving there (they're half an hour away), picking them up a few days later, and then I've had to rent a van because they don't fit in my car...

But I have to experiment with the ply. Assuming I can align them and get them to adhere properly, the main question is whether I can trim the mounted prints using a circular saw (on a straight edge), because they're too big for the table saw.

 

[Ylva]

Problem with foam board is that it dents. The foam in between is very soft. I don't know what you sell these for and I assume you are not interested in protecting them with glass. I also assume the print is on paper?

I think finishing the back is not necessary at all.

 

[nickbatz]

Problem with foam board is that it dents. The foam in between is very soft. I don't know what you sell these for and I assume you are not interested in protecting them with glass. I also assume the print is on paper?

Yes, the medium is printed pigment ink on fine art paper, i.e. the print is the original art - they're limited edition prints. I describe it as an evolution of painting - I make them in a computer, and I use heavily transformed photographic textures and shapes (to oversimplify).

The paper is Canson Arches 88, if you know papers, I use only OEM archival pigment inks, and multiple coats of Moab Desert Varnish to protect it (which is invisible). Arches 88 is very durable, as archival as it gets (acid-free, no OBAs, etc.), made of cotton, and it feels sort of like wallpaper rather than photo paper. You'd have to bump into the picture to dent it, although you're right that it is possible.

The gallery price is about $2-5K, and the problem with glass is that even museum glass detracts from the "texture" - certainly not that I object to the protection it offers! We've had extensive discussions here about that before, and I do get that this is a compromise.

I think finishing the back is not necessary at all.

Thanks, I like hearing that.

 

[Bruce Papier]

Did you say you're thinking of mounting the prints directly to plywood? If so... Oh, No! The plywood will eat the prints no matter what you do. The texture of the wood will likely show also.

 

[nickbatz]

Did you say you're thinking of mounting the prints directly to plywood? If so... Oh, No! The plywood will eat the prints no matter what you do. The texture of the wood will likely show also.

Hm.

Well, the texture won't show, because the paper is very heavy.

But if the plywood will eat them... that seems sort of bad. A local artist whose work I liked at a recent street fair does it that way - that is, gesso on ply. I'm not a fan of eaten prints, though.

Thanks.

 

[wpfay]

The advantage of aluminum or ACM panel is that they are both "non-donor", meaning they bring no damaging chemistry or physics with them.

Gesso is not a barrier to acidic migration. The only true barriers are metallic or glass based. Gesso is porous.

Coatings on the surface of digital prints are also gas permeable, and the UV claim is more for the coating than the substrate beneath.

Bruce's comment ^^^ is spot on. Wood based mounts are loaded with acidity and other oxidizing agents.

As far as the foam centered board mounts, they are not designed to be used outside a closed frame. They are very reactive to environmental changes, especially when something is bonded to one side of the panel. The surface papers may be "archival" but the core foam isn't.

Your solution is clever, and I can see how you got there, but full support is better, and not with a highly acidic substrate. Check into using polyflute (fluted propylene panels) for the support beneath the mount (much easier to cut to size than plywood) and totally inert (if you get the right kind).
If you end up choosing to mount to ACM panel, much of the rest of the challenge will be easier.

You are commanding a retail price that should come with certain security in the acquisition.

 

[Ylva]

The mounting of the print to Coroplast is something you might be able to do yourself. Since the paper is heavyweight, the flutes should not show.

You can wet mount it, then dry under weight. (Practice on a blank piece first)
This solution would require you to do more of the work, but might be about the same price and definitely would be more secure than foam board.

when foam board gets damp, it will bow. It can crease, dent, warp, anything. At that price point, as a consumer, I would expect a better solution.

( I remember the previous discussion )

 

[Finest Fabric]

Echoing what some have already touched on...

The foam board treatment does not bode well for long term stability
and preservation of a valuable artwork.

If damage of any sort does occur it would be a nightmare for a conservator to
correct and might be impossible depending on the type of damage. (i.e. water damage)

An informed buyer might steer clear of investing in such a piece.

ACM would be a much better substrate

 

[nickbatz]

The mounting of the print to Coroplast is something you might be able to do yourself. Since the paper is heavyweight, the flutes should not show.

You can wet mount it, then dry under weight. (Practice on a blank piece first)
This solution would require you to do more of the work, but might be about the same price and definitely would be more secure than foam board.

when foam board gets damp, it will bow. It can crease, dent, warp, anything. At that price point, as a consumer, I would expect a better solution.

( I remember the previous discussion )

I hadn't heard of Coroplast. That looks interesting, and the prints would definitely not show. Thanks.

What would you use to wet mount the prints to it - bearing in mind that my prints are as much as 6' long? I've been using Lineco glue to mount the foam back to the ply, and of course I used weights.

By the way, the foam is flexible and glued down to the ply at the ends, so it seems unikely that warping or buckling would be a problem (again, this isn't Gatorboard). But if there's a better solution, especially one that lets me avoid having to go to the frame shop, I'm all for it!

Bruce's comment ^^^ is spot on. Wood based mounts are loaded with acidity and other oxidizing agents.

Okay, I won't do it.

As far as the foam centered board mounts, they are not designed to be used outside a closed frame. They are very reactive to environmental changes, especially when something is bonded to one side of the panel. The surface papers may be "archival" but the core foam isn't.

Your solution is clever, and I can see how you got there, but full support is better, and not with a highly acidic substrate. Check into using polyflute (fluted propylene panels) for the support beneath the mount (much easier to cut to size than plywood) and totally inert (if you get the right kind).
If you end up choosing to mount to ACM panel, much of the rest of the challenge will be easier.

You are commanding a retail price that should come with certain security in the acquisition.

Well, it's not dog poop. Without wanting to sound too argumentative, I did ask quite a few people about the best way to do this, and this foam - again, with pH-balanced or acid whatever-free adhesives on both sides - was the consensus everywhere but here, where people mentioned ACM. The bad stuff from the thin ply would have to get through a continuous adhesive barriers on both sides of the foam.

Also, if I weren't happily married I'd propose to Canson Arches 88. It's really great, and I tried a lot of them.

 

[JFeig]

You might want to expand your knowledge with information from people in the field of art conservation such as American Institute of Conservation, https://cool.culturalheritage.org/ Conservation OnLine (CoOL) and other educational based groups. As picture framers we use these types of sources for our information.

 

[wpfay]

Well, it's not dog poop. Without wanting to sound too argumentative, I did ask quite a few people about the best way to do this, and this foam - again, with pH-balanced or acid whatever-free adhesives on both sides - was the consensus everywhere but here, where people mentioned ACM. The bad stuff from the thin ply would have to get through a continuous adhesive barriers on both sides of the foam.

Please understand that, as the artist, you can make whatever decisions about your art you want to, assuming you are relatively transparent to the end user of just what that is.
As framers, we do not enjoy that position as decision maker and are somewhat obliged to inform our customers of the shortfalls of any particular process. It is then up to them to provide informed consent to what we do. Since no solution is perfect, it is a choice between how much risk vs. the cost of incremental improvements.
In handling a customer's piece of art, we assume certain liability for its safekeeping and preservation.

As for the "bad stuff"' having access to your art, the mount isn't the sole issue, and surface coatings don't provide a complete vapor barrier. There are a number of household pollutants in things like carpeting and cleansers that get into the inside atmosphere and can accelerate oxidation.

You have the final word in how your art is treated. We can only provide information that is pertinent to that decision.

 

[monkframe]

I've been searching, and I think it's just backing paper that I need. It won't really do anything, though, and I'd have to remove those cross pieces on a lot of pictures to put it on. Also, I haven't seen any that's wide enough for the big prints (the max is 36", and some of mine are 44" wide).

Maybe I should just leave well enough alone...

They look neat and tidy, I wouldn't add anything else.

 

[Ylva]

I have used the Lineco glue to bond mat board to coroplast. I apply it directly to the coroplast, then spread and smooth it out evenly with a small piece of mat board. You could consider using a roller to apply as well. You can let it dry a little bit so it is tacky, not completely wet. Then dry under weight. 6' pieces might be a bit of a challenge for sure!
Coroplast is easy to cut on a wall cutter, but I have cut it with just a utility knife for larger pieces and it works well.

I would not trust foam board long term. The acid free is the surface paper, the foam is still the same and I have seen that foam compressed/crumbled/dried out or swollen because it got damp. It's just not a stabile mounting solution as in your scenario, it is exposed more to the environment. Coroplast is light weight, sturdy, easy to handle.

For better adherence, you can sand it a little bit/roughen it up so it has more grip for the glue.

 

[nickbatz]

Okay, time to order a piece of Coroplast to try it out. Thanks.

I don't have a wall cutter, just a Rotatrim, but it maxes out at 48" and I think the Coroplast is too thick anyway. So I guess it's a utility knife.

Thanks for the replies!

 

[nickbatz]

Then dry under weight. 6' pieces might be a bit of a challenge for sure!

I'll definitely recruit help aligning the large ones (most of my pictures are in the 3-1/2' range), but as long as it can be repositioned this seems entirely feasible.

The real reason for this post: is 4mm thick Coroplast the right weight, and does anyone have a good source for both trial and large pieces? I'm in Los Angeles.

TIA

 

[Ylva]

You can double up on the Coroplast for larger pieces, cutting them so the flutes are crossed. That gives it extremely good stability. I stock 6mm only.

Not sure where you can buy it. Do you have a business license/re-sale certificate?

 

[Bruce Papier]

Check with anyone who supplies sheet plastics for the best price. If you don't mind paying retail, Home Depot should carry it.

 

[wpfay]

The generic name is Polyflute, and you will want the one with the least additives. Some of the stuff they add to extend the life as yard signs (UV blockers), or allow printing directly to the surface (sizing), or enhance their visibility (optical brighteners) aren't necessarily archival.
As Bruce mentioned, Plastics suppliers, and paper suppliers, as well as sign manufacturers can be sources for polyflute.
I agree with Ylva on the 6mm thickness.

I would only use it as a secondary support, and mount a primary support (like 4-ply rag matting as Ylva mentioned) to the polyflute.

 

[nickbatz]

You can double up on the Coroplast for larger pieces, cutting them so the flutes are crossed. That gives it extremely good stability. I stock 6mm only.

Not sure where you can buy it. Do you have a business license/re-sale certificate?

I don't have a business license, but I ordered a 1/4" piece from Amazon to try. EDIT: it's pretty easy to get a resale license, though - I had one in the past when I was publishing a magazine.

But my plan is - I think? - to continue using the 3/8" ply slats to attach the Coropoast (or Polyflute), so I'm guessing that stability won't be much of an issue.

What I do wonder about is cutting the pictures with a reverse bevel to hide the backing. I don't know how well that'll work with the flutes, i.e. if the cut is between two of them.

Thanks as always.

 

[Prospero]

I'll probably get shot at for saying this but.....

I would go for MDF all day long in preference to ply. OK, MDF has it's foibles but if you treat the back and edges with a good varnish
it will go a long way to prevent moisture incursion. Ply can be treacherous. It comes in varying qualities and can be prone to warping/twisting
and sometimes delamination. I have framed many oil paintings done on 9/12mm MDF panels with considerable value and they have always
had the backs and edges sealed.

 

[Hannah R]

Okay I'm convinced I need some coroplast too! Other than Home Depot and plastic suppliers, where do you buy yours? I found that Uline carries it, is theirs good quality, ie good enough for framing?

 

[Mary Beth van der Horst]

Okay I'm convinced I need some coroplast too! Other than Home Depot and plastic suppliers, where do you buy yours? I found that Uline carries it, is theirs good quality, ie good enough for framing?

Omega is one fairly widespread distributor that carries it. They call it Fluted Polypropylene. AFP4896. I price compared it to Home Depot and its around $23-26 per sheet vs $35

 

[wpfay]

The one you want is Coroplast brand name 100% polypropylene if you want what conservators and museums use. It's not all that easy to come by as the manufacturer, last I knew, is in Canada and they only sell in bulk. I used to buy it from SmallCorp (a sponsor of the G) in Ma. but they no longer sell supplies as far as I know.
Bainbridge once handled it and it could be had through LJ, purchased by the 48" X 96" sheet.

If that or an equivalent is what Omega offers, that's good news. The down side is the cost of acquisition (freight).

The other brands and generic items often have additives that are undesirable in a closed frame environment. Coloring agents, optical brighteners, sizing treatments, etc.
If that isn't a concern, the sourcing through Plastics suppliers is probably your most economical way to go. They should be able to provide specification sheets on each of the products.

 

[Mary Beth van der Horst]

If that or an equivalent is what Omega offers, that's good news. The down side is the cost of acquisition (freight).

The other brands and generic items often have additives that are undesirable in a closed frame environment. Coloring agents, optical brighteners, sizing treatments, etc.
If that isn't a concern, the sourcing through Plastics suppliers is probably your most economical way to go. They should be able to provide specification sheets on each of the products.

Here's what Omega lists of their fluted polypropylene:
"Archival fluted polypropylene sheets similar to Coroplast, is acid-free, neutral pH with no dyes or additives. Also available in 6mm thickness by request."

Seems pretty legit material-wise. You are right of course that shipping will be stupid. I am blessed to have been added to Omega's delivery route recently so... no more trips to Home Depot for me! I couldn't even fit it in my car without standing in the aisle and cutting the board in 2 or 3 with my box cutter before going to checkout.

 

[wpfay]

Here's what Omega lists of their fluted polypropylene:
"Archival fluted polypropylene sheets similar to Coroplast, is acid-free, neutral pH with no dyes or additives. Also available in 6mm thickness by request."

Seems pretty legit material-wise. You are right of course that shipping will be stupid. I am blessed to have been added to Omega's delivery route recently so... no more trips to Home Depot for me! I couldn't even fit it in my car without standing in the aisle and cutting the board in 2 or 3 with my box cutter before going to checkout.

HD customer: "Look out, she's got a knife...

and she knows how to use it!!!"

That's great you have delivery on sheet goods. It's also encouraging that a supplier is expanding their delivery area as opposed to most that are doing the opposite.

 

[Ylva]

Now if only Omega would extend their route to include me. I have had multiple conversations.
Anyway, I get it from Donmar and they have different sizes. I stock 40x60

 

[nickbatz]

Thanks for the replies.

Omega is local (Los Angeles), but 4'x8' sheets don't fit in my car. I'll have to give them a call.

In the meantime, I ordered a 4mm sheet from Amazon - a little smaller - that I'll try out as soon as I get a chance. It's probably not archival-oriented, but I'll get a feel for how well it works.

I would only use it as a secondary support, and mount a primary support (like 4-ply rag matting as Ylva mentioned) to the polyflute.

That's cruel *and* unusual. I'll settle for either one, but not both!