Bowing of Mounts / Spacers for Prints

[RobM]

Morning All,

A couple of questions on vaguely related subject...

1. I'm framing a picture with a 5mm spacer to keep everything away from the glass. A problem is occurring whereby the mount appears to be bowing whenever I put in even a couple of points. See the two pictures.

I can see why this could be a problem in this arrangement due to the space in front of the mount, but is there any way around it? Has anyone experienced this and how did you get round it?

2. I'm framing a (seemingly limited edition, though I'm not sure how limited) print for a client, who asked for no mount. This is ordinarily fine, but then would there be a concern from a conservation standpoint about the art touching the glass? Is is normal practice in these situations to put a narrow spacer in to maintain a gap in this sort of arrangement?

Thanks!

[JFeig]

The most obvious question in my mind is: how tight is the fastening of the frame package into the frame? IE: did you have to apply downward pressure to make it all fit into a very shallow rebate?
If so, the answer is to reduce the downward pressure. This might require some sore of extension or modified hardware to the back of the frame to allow assembly.

[prospero]

It doesn't seem to me like it's the mount that is bowing. It will be the backing board.
The side on the outside is exposed to the environment while the inside is sheltered, so
if it's on a damp wall or the atmosphere itself is a tad humid then one side will tend to swell
and bow outwards while the other won't. It's a very fine difference but enough to warp the board.
If you are employing a proper 'book mount' arrangement (you should!) with a stout backing board
then one sneaky trick is to fix a piece of mountboard to the back of the undermount - in register
with the window. The dropout is as good as anything. This imparts a tiny bit of bias and keeps
everything tight. Snip the corners off the dropout so it sits better.

[JKX]

The problem is there’s no glass against it!

The solution - seeing as for some odd reason you must like the look of that spacer, as it provides zero function - is to put it outside of the glass. It would need to be wooden or plastic or something.

Failing that, stick the undermount to the back of the window mount, as close to the artwork as possible - a platform mount uses that method, plus mounts the artwork for you with zero adhesive.

Regards glass against artwork, no! Acrylic would be better.

If you're going to use glass and a spacer then the spacer shouldn’t rest on the artwork unless the artwork is stuck down.

[Justintime]

Make sure that the backing board has some expansion room too, likewise for the mounts. Too tight and it can cause issues as soon as it changes environments. I've had a piece hung on an external wall of a stone cottage, it all bowed within 24 hours. Within a few hours of being returned to me it had settled back to normal. In the end the solution was to replace the backing board with fluted plastic Corri board and replace the backing tape with builders silver insulation board joining tape. No more issues.
2. Yes, for a conservation standard job the artwork should always be spaced off the glass. This can be done with a spacer or a slip, ensuring that the artwork is not held against the spacer/slip, preventing it from expanding and contracting. If the artwork is likely to come into contact with the frame itself, then a frame sealing tape should be used to create a barrier between them.

[prospero]

The problem is there’s no glass against it!

Oooops.... I missed that part.

Yes, that's a good way to make everything curl up like yesterdays cheese sandwich.

[RobM]

Thanks you everyone for all the helpful responses. There's a few things for me to take in there.

Jerome - after seeing your response, I simply held it all down lightly when putting in the points, and put the bare minimum of points in, and it's now at least acceptable (though it's just a frame for myself).

Prospero - this is actually occurring when putting the frame together in the first place, without any adverse conditions (yet!) causing it, though I'm glad you raised that so I can be mindful with this sort of arrangement in future.

John - I know of your dislike of spacers haha! I've used the method of sticking the undercount to the back of the top mount a lot but have actually gone away from doing this of late because I'm finding cutting the undermount to be a little problematic and I've had many such windows looking frayed or uneven (presumably the undermount sags slightly within the already-cut window of the top mount when in the mount cutter).

Justin - I'm going to bear in mind the alternative tape and backing materials you're suggesting when dampness is a real problem in future. For the conservation standards you mention, how would it work if the artwork is not held against the spacer? I don't quite understand that bit. And for frame sealing tape, would you use something like the Lineco foil frame ceiling tape?

I'm starting to wonder if it would be more worthwhile just cutting a 5mm mount to sit within the moulding rebate. Does anyone do this?

[Justintime]

The artwork would be hinged onto board and then adhered to a board below, as in floated with a shadow, or you cut a window and hinge the work to the fallout and then secure the fallout back into the window, as per the Hedgehog technique.
Yes exactly, the Lineco frame sealing tape, with the self adhesive aluminium one side and the acid free white paper on the side facing the artwork. It just prevents any migration of lignins/acids from the wood to the work.

[RobM]

Like this? Really useful method.

[Justintime]

You're asking about mountboard spacers. Yes lots of us do that. I glue a length of mountboard to a length of 3mm foamboard then cut out the spacers required from the piece of board. To hold them in I use a combination of self adhesive tape and glue, a few bits of self adhesive distanced along the length will secure the spacer while the glue goes off. The preferred method is to place the top and bottom spacers first followed by the two side spacers. In the event that the glue fails on the top spacer, the side spacers will keep it in place.

[Justintime]

Yes exactly. Roy Rowlands' framing business was called Hedgehog Framing hence it being known as the Hedgehog technique. I only wish Lions would get on board with the commonly used terminology!

[RobM]

But why get the foam board involved (unless for achieving depth)? I'm just meaning to use the thin strips of mountboard to come into contact with the print, avoiding it touching the glass directly.

You're asking about mountboard spacers. Yes lots of us do that. I glue a length of mountboard to a length of 3mm foamboard then cut out the spacers required from the piece of board. To hold them in I use a combination of self adhesive tape and glue, a few bits of self adhesive distanced along the length will secure the spacer while the glue goes off. The preferred method is to place the top and bottom spacers first followed by the two side spacers. In the event that the glue fails on the top spacer, the side spacers will keep it in place.

[JKX]

Mount board isn’t thick enough on its own to provide enough support for glass. Standard thickness is less than the amount of play you can leave for giass!

5mm foam board is but only comes in black or white, so mountboard bonded to 3mm foam board is almost as thick.

I do like glass spacers, but not if they aren’t functional. I have reproduced regimental colours and all sorts in rebate spacers.

Pay more attention or I’ll write you off as a lost cause!

I have no idea what you’re on about above ref under mounts stuck to back of mount!

[RobM]

You're busting my balls again, John Some tough love is a good way to learn though!

Mount board isn’t thick enough on its own to provide enough support for glass. Standard thickness is less than the amount of play you can leave for giass!

5mm foam board is but only comes in black or white, so mountboard bonded to 3mm foam board is almost as thick.

I do like glass spacers, but not if they aren’t functional. I have reproduced regimental colours and all sorts in rebate spacers.

Pay more attention or I’ll write you off as a lost cause!

I have no idea what you’re on about above ref under mounts stuck to back of mount!