After stabilization

I just realized I’ve neglected to post some after treatment images of the first panel, which was completed quite a while ago. We are now finishing up the third of four panels. Here is panel 1.

For comparison purposes, here are a couple “Before” views of the lower part.

Although the quality of these images is not great,  I’m happy to say that we’ve since upgraded to a DSLR camera and improved the photography setup (following the AIC Guide to Digial Photography and Conservation Documentation, 2nd edition), so future images should be much better!

The next post will be about an entirely different project, a ceramic tile mural…

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Back on track

It’s been a while since the last post. We have been busy with multiple  projects and there’s been little time to pause and reflect on the treatment of the leather panels.  In the meantime, some progress has certainly been made. Consolidation and reinforcement of the trim is complete, and we have now turned our attention to the main structural damage, namely the large tears near the bottom of the panel. All that stabilization was essential before we could safely turn the panel face down to begin the next phase of treatment.

As I mentioned earlier, the area of damage was consolidated with Pliantex solution from the reverse. (Due to both the limited budget and to minimize the extent of damage, the old paper backing was removed locally around the tears/splits, rather than overall.) For additional strength–so that the leather is sound enough to withstand having something adhered to it–we also applied a dilute solution of BEVA 371 in the areas immediately surrounding the tears to be mended.  The repair will consist of lining the tears and areas of separation with narrow strips of Hollytex/BEVA film on the reverse. Then the old canvas backing we temporarily removed to gain access will be reattached to maintain uniformity in the structure of the layers.

From the front, the losses and gaps will be filled with BEVA Gesso mixed with powdered pigments to more closely resemble the color of the leather,  plus glass microballons to make the fill lighter/ less dense. Some final toning of the fills as well as the Goldbeather’s skin used for reinforcing the edges may also be necessary to reintegrate the surface appearance. Then we will add a rigid backing made of several layers of acid-free corrugated board laminated cross-wise, over a cushioning layer of dense polyester batting. This backing is the most important measure in protecting the panel from future damage. But that’s not quite the end…we will move on to the other three panels in the group. Undoubtedly, this will be a year-long project at the very least.

Somehow, I would really like this blog thing much more if it were a dialogue wherein ideas could be shared. I am very open to other ways of thinking and approaching the conservation of leather, so I would love to hear what techniques and adhesives others are using. Do you consolidate to strengthen the surfaces prior to mending? What are your preferred adhesives and loss compensation materials (other than BEVA)? Any comments or feedback you’re willing to share would certainly be appreciated!

(After treatment photos coming soon!)

More than meets the eye: fun with a nifty gadget

Fine Arts Conservation recently acquired a wonderful new tool for use both in our studio and in the field: a portable digital microscope camera that connects to a laptop’s USB port and takes fairly good quality images. It’s a Dino-Lite Pro model AM413T with 1.3 M (1280 x 1024) resolution, and it’s surprisingly affordable at less than $400, software included. Many other models are available, but it seemed this one with a magnification range of 10x – 220x would be most useful for documentation purposes. We are loving it so much that I just had to share some images we captured of various things in the studio. The first is of the old familiar deteriorated leather panel we’ve been discussing.

an area showing leather deterioration from the painted leather panel we're working on; this is what red rot looks like (untreated) at 200x magnification.

Below are some fibers from another object we treated recently:

Parallel pastimes

(In case you didn’t know… yes, we work on upholstery too!)

Another interesting project underway at Fine Arts Conservation this month–especially if you like chairs, as I do:

Glass chair with zebra upholstery, 1947 (after a 1939 set of chairs made by the Pittsburgh Plate Glass Company for the Glass Center Pavilion at the 1939 New York World’s Fair) attributed to the designer Louis Dierra. Other examples of this chair can be found in the collections of the Brooklyn Museum and the Carnegie Museum of Art.

The chair looked like this when it first arrived at our studio:

Concealed beneath two layers of ugly modern upholstery and excess padding, we discovered the original upholstery, which is this wild zebra pattern fabric (so wild, you have to love it!)

Sadly, the first re-upholsterers slashed away the piping used to define the edges, disfiguring the original upholstery and making it unfit to be exhibited.

There was nothing to do but try to find an appropriate replacement fabric that matched the color and texture of the original, and (also very important) the size of the pattern’s repeat. After much searching and with the help of a curator in New York, we finally arrived at this excellent  match made by Artek for Alvar Aalto designed chairs. The fabric is of very good quality and was quite expensive at $255/yard. It has exactly the same repeat size as our original zebra, though a slightly more irregular (and natural) stripe pattern.

This is what the chair looks like now, with the new upholstery.

We left the original fabric in place, isolated it with an undercover of washed, unbleached cotton muslin, and added a small amount of resin-free polyester batting to even out the shape. The new fabrics are attached to the plywood seat bottom over Nomex strips with a minimum number of stainless steel staples driven with a pneumatic staple gun at less than 40 psi. The latter is intended to minimize damage to the plywood from the metal fasteners.

The treatment of the crack in the glass was not as successful. The crack was so tight that we could barely get any HXTAL to flow into the crack, even after warming it. A little went into both ends, which suggests that at least the crack  is stabilized and won’t continue to “grow”.

However, filling of the loss in the bottom edge of the glass worked out well. The fill was cast in place using HXTAL and a silicone rubber molded impression of the texture of the original glass.

loss before filling

loss filled with HXTAL NYL-1 and textured to match

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See “Prophetic Panorama,” House and Garden, July 1939, p. 25 for a color rendering of the chairs at the 1939 New York World’s Fair.

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Here is a 1939 postcard from the fair, showing the Glass Center building

The Glass Center erected at the New York World's Fair 1939 has a floor area of 25,000 square feet and contains the exhibits of three leading glass companies. Corning Glass Works, Owens-Illinois Glass Company and Pittsburgh Plate Glass Company. The tower, 108 feet high is constructed of blue plate glass and glass block.

Diversions

Following the suggestion of one of my great helpers, I made up this recipe for a “red rot cocktail”–the kind you would drink that is, and not to be confused with the Klucel/SC6000/ethanol mix for treating powdery leather!

Red Rot Cocktail 2:

1.5 oz. vodka

3 oz. pomegranate juice or pomegranate-cherry blend

a dash of powdered cayenne pepper

the juice of 1/2 lime

Pour into a cocktail shaker over ice, shake well, and strain into a cocktail glass.

Add a sprig of fresh mint for garnish (optional).

Cheers!

Then I thought I’d better check to make sure there isn’t already something like this out there, and sure enough when you Google “red rot cocktail” this link comes up: Red Rot Cocktail . Their version sounds really good as well! Don’t know how or why they chose to name it as such though. 

Let there be multiple variations, since anything goes… But it should have something remotely to do with powder (e.g. cayenne) and be red in color to adhere to the theme.

Sounds light and refreshing with a kick, nice for a festive Sunday afternoon party. If anyone tries this, let me know how you liked it. I haven’t actually had it myself (yet!) so the proportions in my recipe could be slightly off and may need some fine tuning. Or better yet, come up with your own suggestions for red rot cocktail!

Next time, back on track to more serious matters.

Related Articles

• Pomegranate Martinis (alldrinksconsidered.wordpress.com)

Stabilization continued: Considering reinforcement of the fragile edges (and talking to inanimate objects!)

Because of my not-so-secret love of paper, I was planning to use toned Japanese tissue for some of the repairs, such as reinforcement of the fragmentary edge trim. But now I’m thrilled and want to thank my good friend and colleague Rhonda Wozniak for sending me a sample of Goldbeater’s skin (made from the outer membrane of ox intestine) to experiment with. I’ve never used this material before, preferring to stick with Japanese paper and non-woven polyester fabrics like Hollytex or Reemay. Now I’m wondering: why not? It turns out that Goldbeater’s skin is perfect for the intended application–it is thinner, smoother and more translucent than paper, and about as strong. It conforms better to uneven surface topographies. It can be pre-toned just as easily as paper, but only using non-aqueous based paints such as Gamblin or Golden MSA colors. Goldbeater’s skin is fairly reactive to water, and even the small amount in acrylic paints causes it to swell, warp, and become cockled. I will be adhering it using 1 mil BEVA 371 film activated with a heated spatula. More on this later.

This week I felt the need to take some time off from the demands of our leather project and have a little fun with a few of my studio helpers instead. In the spirit of Easter, I convened my bunny weights and advised them to stay put, keep out of trouble, and watch out for those volcanoes! We shared some crunchy kale… now they’re alert and standing by, ready to help with the next phase of the treatment. You’re probably thinking the solvent vapors have gone to my head…

The stylin’ resin bunny and volcano weights are courtesy of Inherent Vice Squad (www.inherentvicesquad.com). IVS has a lot of other cool and very handy hand-made accessories, so check them out. And Happy Easter to those of you who celebrate it!

Stabilization is fundamental

Sadly, leather afflicted with red rot can never be brought back to its original healthy state again. The weakening and embrittlement are irreversible. All the more, it is essential to consolidate the powdery leather to strengthen it before undertaking any tear repairs, otherwise the repairs simply won’t hold and the leather will crumble apart. Our solution to the problem is described below.

Consolidation: For the trim leather, I found it best to use a combination of consolidants, taking advantage of each of their favorable properties.  Not having enough Pliantex to treat all four panels, I am reserving it for the cracks and splits in the varnished main sections of leather that are sensitive to alcohol.

The following system evolved from my mock-up trials for consolidating the trim, and is working really well so far: I brush-apply (fairly liberally) two consecutive coats of 1% Klucel in ethanol—it easily penetrates and almost immediately disappears into the leather; this is followed by an application of 2% Klucel; and finally, an application of the Klucel/SC6000 mix (equal parts of SC6000, 2% Klucel in ethanol, and ethanol) which mostly seems to sit on the surface and seal it. The latter adds strength, seals the surface, and dries to a nice sheen that is in keeping with the original finish. To get the solution underneath the lifted bits and edges of the trim, a small syringe works better than a brush.

For the main painted/varnished areas, Pliantex will be used exclusively, as it is the only material that seems to work (hoping that we don’t run out before the end of the project).

Keep in mind that all of this is just part of the preparation for lining tears and securing loose bits of the fragmentary trim. Without consolidation, it would be impossible to adhere anything to the powdery leather, since it would just flake or peel off almost immediately.

Incidentally, I did some preliminary tests on a scrap piece of leather (flesh side) consolidated with various dilute adhesives, then adhered strips of non-woven polyester to it with BEVA 371 film by heat-setting. When I qualitatively tested the peel strength of the Beva/fabric, I was surprised that the leather fibers broke and gave way on all the samples except for Pliantex. The strip was nearly impossible to peel off the sample consolidated with Pliantex since the leather fibers would not break. This tells me that it’s superior in strength to the other agents of consolidation commonly used for powdery leather.

Here is what an area of the border looks like after consolidation. The color of the leather has darkened somewhat due to saturation, which is inevitable, but it has gained significantly in strength and flexibility.

Compare to the same area before consolidation.

By the way, does anyone know why Pliantex was discontinued? If someone has found a source or reasonably good substitute for Pliantex, please, please let me know!

I will be adding more info as the treatment progresses. Next up will be reinforcing the  loose fragments along the edges, and then later on I’ll discuss the process of lining tears and splits.

Reflections on powdery leather

Developing a treatment plan: The main challenge has been finding the right consolidant, one that will improve the leather’s strength so subsequent repairs will hold. I have plenty of experience working on leather artifacts, and know what the limited options are when the leather is this degraded. Klucel G works well in the short-term (it has good penetration and effectively consolidates the powdery surface) but is relatively weak, and is known to have a short lifespan of usefulness. What’s more, Klucel is fairly brittle and has shown unsatisfactory long-term ageing characteristics, particularly in an acidic environment such as that encountered with deteriorated leather (e.g. in the presence of sulfuric acid from absorption of sulfur dioxide in the atmosphere).

I recently began using Klucel/SC6000 mixture with good results in terms of improved strength and flexibility; the problem is that it tends to sit on the surface and does not penetrate into the leather structure very well. I’ve also used Pliantex in the past with a very good outcome. Despite the nasty smell of the solvents, it has excellent penetration and imparts sufficient strength and improved flexibility to the leather. Unfortunately, this product has been discontinued and is no longer available!  (We happen to have a small supply left over from a similar treatment we did some years back–possibly just enough to last through this project.)

This is a dilemma we all struggle with at some point in our careers as conservators. It is understood that any consolidant introduced into a porous material such as leather, is for all intents and purposes, not reversible. It would be nearly impossible to extract the consolidating agent from the porous material completely. And why would you ever want to, as long the material is stable and is not causing any harm or threatening the future stability of the object in question? There are really only two choices: 1) either to do nothing at all and let the object continue down the path of deterioration and eventually cease to exist, or 2) do something that we’ve been taught to avoid, something that defies our ethical sensibilities—that is, something not readily reversible—and by this intervention, ultimately allow the object  to survive for future generations to enjoy.

A description of the actual treatment (so far) is coming soon…

The challenges of working with degraded, powdery leather—Four panels from a painted leather screen

A bit of background on the panels: in another life they formed a screen, but it appears the leather was cut from something originally larger (possibly wall paneling in a room, or an even larger screen). This is suggested by the sharp cut lines along the edges and the fact that part of the painted/embossed border design has been trimmed. The wood frames to which they are now attached appear to be relatively recent. Narrow strips of leather secured with brass nails were added to cover up the cut edges.

Each of the four panels is comprised of  two sections of leather stretched over a wooden  frame. The leather is embossed and painted with floral and animal/bird motifs. The surface is varnished overall and stained to give the painted background an “antiqued” appearance.

Current condition: The leather is extremely desiccated and brittle, and shows an advanced stage of a type of deterioration known as red rot. The latter includes overall loss of strength, embrittlement, desiccation, and associated cracking, flaking, and powdering of the leather with resulting breakage and loss of fibers—this is particularly apparent in the leather trim along the edges.

This is what red rot looks like up close:

You can see that the fibers are breaking up and crumbling to dust.

The problem, simply stated, is that the leather is disintegrating. The fibrous structure made up by the collagen protein is literally breaking apart and turning into dust, especially in the trim leather, which is of a different type than the large pictorial areas. The trim is extremely ragged in appearance due to the abundance of losses. There are a number of tears and splits in the primary decorative leather as well, the worst of which is across the bottom of  panel #1 (below). To complicate matters, the varnish on the main leather (but not the trim) is sensitive to many solvents, including alcohols; it is not adversely affected by naphtha or xylene.

A comprehensive discussion of the mechanisms of leather deterioration can be found in Conservation of Leather and Related Materials by Marion Kite and Roy Thomson. I highly recommend this book for anyone that is working with leather.

Oh, I should mention that the backs of the panels have been lined with a layer of acidic paper and a heavy woven cotton fabric. Both are adhered with animal glue! Ugh!! Oddly enough, the fabric does not extend all the way to the edges of the frame, and looks as though it was applied after the leather was stretched onto the frame! Not a well thought-out solution, and clearly not the work of a professional conservator, nor even that of a skilled restorer.

Removing the lining is not really an option because the leather is too weak and the damage this process would likely cause is too great (plus, our dear client has limited funds). Therefore, we will only be removing certain sections, where it’s necessary to gain access to the back for mending tears and splits.

 

Coming up next:  Treatment highlights

Greetings!

Welcome to my blog. I am a sculpture and 3-D objects conservator based in Los Angeles. I love my job because every project is unique, poses new challenges, and presents an opportunity for creative problem-solving! Art conservation has a tiny bit in common with environmental conservation, in that both are concerned with preservation of precious resources–in my case,  it’s our cultural and artistic heritage.

I consider sharing  information with one another to be an invaluable tool in our collective repository. That’s why I decided to write about some of the more interesting projects currently underway at our studio. This is intended mainly for folks who already have some understanding of what conservators do, or want to learn more about it.

My first series of posts will describe the treatment of four leather panels that once formed a folding screen, said to have originated in France (clearly with Asian influence) sometime in the mid to late 19th century.

The leather is severely deteriorated, and suffers from a condition known as red rot.

Much more on this topic (and how I am dealing with it) soon…