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Sheepskin diploma problems


CGF, Certified Grumble Framer
Last month we framed a sheepskin from 1965. It had been rolled up since then so, carefully, I unrolled it and pressed it between weights for a few days It flatened perfectly (even I was surprized. Double mat UV glass acid free back with pressure plate. Looked great. Customer Impressed.

One week later....she's back with it. It looks like a 3D relief map. I've NEVER seen anything like this. I've only ever done a half dozen sheepsins and never had this happen. So far I've been told that the only solution is to drymount, I don't like that.

Exactly how durable is this stuff, can I wet it on the back and use my press to dry it? I'm worried that unlike paper this might make it worse.

Any ideas?
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CGF II, Certified Grumble Framer Level 2
If this is a genuine skin or genuine parchment, absolutely no moisture, absolutely no heat! You will permanently ruin it.

The wrinkling is possibly from heat building up inside the frame and driving out moisture - or - the skin has been hung in a place where there is excessive moisture.

Ask your customer where and how it was hung. Outside wall? Direct sun? Is it a real sheepskin?


Cheryl Crocker CPF GCF

CGF II, Certified Grumble Framer Level 2
I saw this once with a centuries old Gregorian chant written on animal hide. It had not been framed properly and there was mold forming, too. Lately, a lot of the diplomas/degrees coming in have been on paper that looks old. I rarely see true sheepskin. Our state motto: First in pavement, Last in Education. The chant had been hung over a heater.
I'd love to know if there is anything that can be done,too. My client would surely bring the piece back in.


CGF, Certified Grumble Framer
Yes, it is sheepskin. Has a leatherlike texture.

All questions were asked when she brought it back, not an outside wall and not in sun (inside wall office with no windows).

As stated above, it had been in a rolled up for years, maybe it doesn't like being flat? I removed it from the frame imediately and over the last 24 hours it has relaxed a bit, but not enough. Problem is, she saw it flat and wants it returned to that state. I could remount (AF corners) and say " best we can do " but it's a lousy way to encourage a return visit. Surely there must be a way to keep it flat.


If I am following correctly, have you checked with a taxidermist to see if there is anything that can be done?



PFG, Picture Framing God
Chris W, After reading your posting, I remembered seeing a presentation at my chapter PPFA meeting on this very subject. So I asked the presenter to send me the information, this is what he sent:
You can look it up at "mounting artwork-the framer's guide to professional results". (see PPFA bookstore-www.ppfa.com) It can be found on page 50. Ben Baker gave a good way of mounting sheepskins using a product called Lamin-All. Also in PFM on June 1992 there was an article on this type of mounting. He advised that if you have never done this before or seen a demonistration, it might be a good idea not to try this on your clients artwork, but to test it on something that can be replaced. Hope this helps and sorry it took so long.

[This message has been edited by BUDDY (edited 05-15-99).]


CGF II, Certified Grumble Framer Level 2
Hi ChrisW

This is going to be a somewhat long explanation, but an understanding of the dynamics of the problem is necessary. I'm not going to edit this.
I suggest that you get a coffee.

The sheepskin is very hygroscopic i.e. it absorbs water - from its environment. (It also releases water, if its environment is dry.)

As it absorbs moisture it changes shape; the skin's cells expand one at a time, increasing their volumes, one at a time, until they either absorb what moisture is available or until they have reached their capacity.

As the cells fill out, they increasing the volume of space that they occupy - but - they do not do this at the same rate nor with equal capacities - which causes differential expansion to occur.

Natural skins (as do some plastics) have a "shape-memory". This is a naturally-occurring phenomenon in all organic matter. As the skin expands it is simultaneously subject to its "shape-memory" and to differential expansion, which results in the very exaggerated cockling that you see.

The procedure reverses if the environment is dry: the skin gives up its moisture to the environment.

When rolled up and stored, the skin's moisture content was in equilibrium with that of its storage environment in the customer's house. Its shape was determined by the walls of the tube in which it was rolled.

When it was removed from its storage tube in your shop, it undoubtedly stayed tube-shaped and did not just flop out flat on the table, did it? When opened flat, it wanted to roll up again, right? - shape-memory.

You unrolled it and sandwiched it, "for a few days", between weighted matboard, to flatten it. While sandwiched, the skin acclimatized to the new moisture levels in its new environment - between matboard which was stored in your shop (same moisture level as the rest of the environment in your shop) and in the RH present in your shop. Its new shape was determined by the weighted matboard i.e. flat. This, I assume, is where your customer saw it in its "flat" condition.

It was conservation framed under a window mat, then taken by the customer, to a new environment - where it promptly changed its shape. Its new environment also had a new RH - but, with nothing to constrain it or force it to keep its flat shape - the window in the mat allowed it to move unrestrained, and with the help of some shape-memory, it ended up looking "...like a 3D relief map."

It is my understanding that there is not a whole lot that can be done to change this phenomenon, if skins are to be treated in a conservation manner. Natural skins will behave, well, naturally, and unfortunately, if you will excuse a really bad pun, it's the nature of the beast.

In an ideal world, its cockling may be minimized (but not completely controlled) by making an effort to keep the scope, frequency, and the rate of change of its immediate environment, particularly that of RH, reduced.

Scope and frequency - Ideally, the skin should be flattened out and framed in its destination environment, or in an environment that closely duplicates it, particularly in regards RH. Since it will not be moving through differing environments, the frequency of environmental change will have been automatically reduced to zero.

Rate - Since an environmental constant, once at the frame's destination, cannot be guaranteed, steps should be considered to reduce the rate at which potential changes to the skin's environment inside the frame package may occur.
Conservation frame the piece as you normally would: glass, framespace, rag matboards, skin, rag mountboard, rag filler - stop! ...add more rag fillerboards here - it was suggested that three or four boards may be adequate; in this case, more is better - seal the edges of the mat package with conservation-grade tape, fit the package into the moulding, and then install an impermeable backer (or Tyvek, correctly oriented in regards its face) instead of dustpaper.

The goal is to reduce the rate at which changes to the environment inside of the mat package may occur. The tape seal's primary function is to prevent exchange of atmosphere - remember, this is supposed to be done in conditions that duplicate its final destination - if it was assembled initially in a relatively dry atmosphere, so much the better.

The extra rag fillerboards' primary function is to add physical mass that will buffer radical changes in temperature, mass of airflow, and airflow rate inside the package.. Everything is forced to slow down so that the skin can s-l-o-w-l-y and more gently acclimatize.

This is not a guaranteed solution. Some trial-and-error may be required. Be patient - skins are a tough problem. (Was that another bad pun?)

I hope that this will be helpful to you and your customer.


[This message has been edited by Orton (edited 05-19-99).]


CGF, Certified Grumble Framer
Thanks guys. I guess I kind of panic'd at first. I try to be soooooo careful that when this showed up soooooo bad it threw me.

It's been sitting in a quiet corner of my shop for a week and is almost flat again. Watching this thing morph infront of me has been interesting. I will definately pack as many layers as I can into the package to reduce RH change.

I phoned two previous sheepskin jobs and one client remarked that it did buckle every once and a while but usually flatened out again. I think in the future I will attach a summary of Ortons remarkes to the back of all sheepskins.



CGF II, Certified Grumble Framer Level 2
I just took in an Indenture from the reign of George III. It has been folded for many years. We designed it to float so you can see the puzzle edge. How can I hinge this thing with all the puckering and dimpling it must go through? This sucker is huge!


Last week I had a retired ENGINEER come in with a real sheepskin diploma. It had been rolled in a tube for 40+ years. I said, "Do you want this perfect and flat?", "YES", he replied. I then told him there was no way I could do it. I explained the problems and he understood. He decided not to frame it. Detecting a problem and telling the truth is the best method in my book. Engineers you got to love them.

What about encapsulation in mylar if the sheepskin is flat?


One last thought, I advised hime to have a high quality copy made and frame the copy. I showed him some samples of what could be done. He seemed to liked the idea and may be back.


PFG, Picture Framing God
Back in the sixties we used to get quite a few real parchment sheepskins in for framing. Over the years I have mounted more than 100 of them.
The basic procedure for mounting them is simple but scary.
Get four sheets of white blotter paper.
A pile of glass for weights.
Dampen two of the sheets of blotter paper evenly with a spray bottle and distilled water. lay out several sheets of glass on a table that is not used on a daily basis. Lay a DRY blotter paper on the glass, then a dampened blotter paper on top of that.
Lay your sheepskin on top of the dampened blotter paper. Lay the other dampened blotter paper on top of the sheepskin. Follow that with dry blotter paper and at least eight sheets of SSB glass on top of the last blotter paper. You want it to be really weighted so the parchment is absolutely flat against the dampened blotter paper.
Leave the parchment in this environment for at least three - four days.
This is important:
Resist the urge to "Check" on it, do not open the sandwich.
When your ready to open it you must be ready to put it into the glue immediately. If you are not prepared you will end up with a very tightly rolled parchment that is next to impossible to unroll with out a lot of help and colorful adjectives.
Before you open your weighted package, roll an even coat of non curling vegetable glue (Yes Paste works great)onto a piece of four or eight ply rag.
You have to move fast at this point.
Remove the glass weights, pick up your parchment (Do Not allow it to roll up) and lay it into the glue starting at one end,
If necessary brayer it out, be sure to use a cover sheet.
As soon as you have it flat into the glue. Put it back onto the glass sheet, put several sheets of dry blotter paper on top of it. Pile all the glass weights back on top of that.
Let it dry completely for at least three to five days. Again. resist the urge to look at it for at least three days.
I have been doing it this way over my entire career and I've never had a problem.
The ink from the signatures will not bleed as you would think they would, I've never had that happen.
I did have one roll up on me once because I did not have my glue rolled out and ready to go when I removed the weights. You have to be ready and you have to move fast. The worst thing that could happen is the parchment will start to dry before you lay it into the glue, do not let that happen, let the phone ring.



Angry Badger
Le, Had the same problem a few years back. Wanted to see both sides of the indenture as well. Fashioned a clip that fit into the shim between the two sheets of glass. The clips held the very edge of the parchment at top and bottom without causing any tension. The clips were of cherry and finished to match the frames (used 2...back to back). Faced the surface of the clip with rag board.
JRB's technique is familiar to me but I would be scared ****less to experiment on someone else's piece.

[This message has been edited by wpfay (edited February 24, 2001).]
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