The Conservation of Diego Conde’s Carta de La Ciudad de Mexico, 1793

By Karen Zukor, Zukor Art Conservation, Oakland California

Diego Conde’s Carta de La Ciudad de Mexico, 1793, after conservation. Photo courtesy of 42-line Digital Publishing.

Diego Conde’s Carta de La Ciudad de Mexico, 1793, after conservation. Photo courtesy of 42-line Digital Publishing.

Large wall maps have been numerous in our studio the past few years, each one presenting certain challenges. They tend to be of a significant size, requiring multiple people to move them and they usually have been poorly stored and handled. Their size alone almost guarantees that they have been rolled up and wrapped insufficiently. Once opened for viewing, minor problems such as edge tears or lifting areas of paper tend to have been addressed with tape or adhesives that contribute to further damage. Most maps of a certain dimension are reinforced with a cloth backing that, at least initially, allows them to be rolled and unrolled repeatedly - the textile provides support for the less flexible paper. But as paper ages, it often becomes brittle and more subject to breakage/cracking. The fabric can continue to be rolled but the paper map will suffer each time it is viewed.

Wall maps are also often coated with a varnish layer to ‘protect’ the surface; these coatings can bring their own damaging, disfiguring properties.  Varnishes can darken over time and become difficult for future removal. If the coating is, for example, a natural resin and therefore dissolvable in organic solvents, those solvents may affect the printing inks and colors beneath. If synthetic, they may be completely insoluble and not removable at all.

To assess the extent of damage and possible intervention, it is important to know whether the map is valued because of the information it carries, its aesthetic qualities or its rarity. The other factor to consider is the eventual disposition of the map once it is repaired; will it be framed, rehung on dowels and displayed in a private or public venue, rolled up for storage, or digitized and discarded?

Conde’s map was particular in its qualities because of its age and extensive hand-coloring, and the accurate depiction of Mexico City and its environs in the late 18th C. It is baroque in embellishment, with a decorative border and vignettes from city life that illuminate the lower edge. One-third of the entire map consists of a chart or legend of everything depicted in the city; roads, churches, parks, public buildings, cemeteries, etc., all rendered in a small fine Italic typeface. Even in the fields and outer farms, each tiny tree is rendered with a shadow. Because it carried so much information and detail, this map was obviously meant to be studied and referred to. But it had been stored rolled up for many years and the result was a great deal of creasing, splitting and loss in the paper support. The cloth backing was dark and brittle and needed to be removed before the problems in the paper could be addressed. That backing had been applied with a thick adhesive layer that was water soluble – but so was the hand-coloring on the map itself. After a careful slow peeling, the cloth support was removed, exposing the thick discolored adhesive on the verso. Moisture would have helped to remove that adhesive layer but it would also have jeopardized the colors on the front. The decision was made to manually remove the old adhesive with flat microspatulas and scalpels – a very laborious process but a safer one.

Once the verso of the map was exposed, it was humidified by spraying with filtered water, pH 7.5, and the excess moisture removed with blotters. This ‘wet cleaning’ was repeated multiple times, to reduce the overall discoloration and aid in relaxing areas that were creased and crunched. Areas of extreme damage were realigned and held in place with mends of Japanese tengujo tissue and starch paste, before the entire map was backed with two layers of kozo; the first, a very thin toned tissue and the second, a medium weight machine made paper, both applied with thin starch paste. The map was then initially dried under wool felts with a polyester interleaving (Hollytex) and eventually stretched dried onto the table top. This method allowed the map to be gently pulled flat and held in place while the extensive paper losses were filled with toned paper to blend in. So much of the border design was missing that we had it digitized and printed out on tan laid paper (handmade J. Barcham Green). Strips of the design were shaped to fit into place, pasted down and colored to match the adjacent border. Minimal compensation was done with watercolors, to accommodate the variation in tone and was applied only to the contemporary fills.  

The map was then framed archivally, with a Baroque black and gold wood moulding that complimented the complexity of the design. TruVue Museum Optium glazing was employed to preserve the rich coloring of the original but also to protect the fragile paper support from further darkening and embrittlement. Given the size of the map, Optium was chosen as a lightweight, clear, and shatter-resistant protective layer that was ideal for both storage and exhibition.

Published by TruVu Inc.

Diego Conde’s Carta de La Ciudad de Mexico, 1793, after conservation. Photo courtesy of 42-line Digital Publishing.

Diego Conde’s Carta de La Ciudad de Mexico, 1793, after conservation. Photo courtesy of 42-line Digital Publishing.

The Conservator vs. The Earthquake: Volunteering to preserve cultural heritage in Haiti

by Karen Zukor, Zukor Art Conservation, Oakland California

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In August of 2010, I went to Haiti as a volunteer conservator, to help salvage works of art damaged in the catastrophic earthquake in January of the same year. There had been an initial immediate response in the conservation community offering help, but it had seemed to me almost ridiculous in its premise – why repair art when people needed medical help, clean water and immediate shelter. But after much conversation with colleagues and others in the art world, it was clear that Haiti had a very rich cultural heritage worth saving. The country has a history of using art as an expression of celebration, commemoration and popular narrative.

The Haitian tradition of storytelling—including legend, myth and religion—has always found representation in the visual arts, and there was a profusion of painting, sculpture, and textiles reflecting that diversity of culture. If the country lost a large part of its patrimony because of extensive earthquake damage, it would also forfeit its considerable artistic legacy. I was curious to go see what could be salvaged, and wary about the chances of making a difference. The security of traveling in such a damaged and chaotic country was also a factor to consider; my friends were not happy with the idea, and my family even less so. What little I knew of Haitian art was compelling enough to make me say yes to the adventure.

A painting conservator from Los Angeles had also agreed to go, and she and I met in Miami early one morning to embark on this trip. We had been asked to bring a number of items with us, to be used in the labs (small tools, lamps, extension cords, batteries, sprayers, etc.), and so we set out with large duffel bags and minimal clothing. Room in our carry-ons was for the work we were about to do, not accessories. Mosquito nets and copious amounts of bug spray, however, were vital. 

The conservation work was sponsored by the Smithsonian Haiti Cultural Recovery Project, in partnership with the Haitian government and a consortium of arts organizations. The project deployed conservators in various specialties for short periods to perform immediate stabilization for artwork that had been recovered.

 Our work was performed at the newly established Haitian Cultural Resource Center, a large building within a former U.N. food bank compound. The offices had been converted to conservation labs for paintings, paper, and objects: fairly well-equipped spaces large enough to perform basic tasks. Previous conservation teams had brought over tools and materials to allow for elemental repairs, but there were also adhesives, chemicals and pigments to perform more sophisticated work.  

The paper lab was large (but mostly empty); I was given a computer to keep track of all treatments and was asked to document the work with photographs. A camera never materialized, so I used my own digital device and took basic before and after images, identified with Post-it notes. There were a few tables, all at standing height, but only one chair. All of my procedures were subsequently done standing.

Adjacent to the work space was a locked room in which were kept the items to be repaired. It should be noted that the majority of salvaged items were paintings and sculpture, including many architectural elements from the main cathedral of Sainte Trinite which suffered extensive damage. The paper lab had nine works on paper and three large volumes.

No direction or prioritization was given; I was on my own. I chose the items that I thought needed the most immediate attention and then those that appealed to me artistically. One piece was clearly a modern reproduction so I set it aside. Eventually I completed seven works on paper: 3 watercolors and 4 drawings.

Not having any oversight was actually quite liberating, and being confined to the Centre kept me focused. From 8:30 in the morning to 6:00 in the evening, there was only this very damaged art and the desire to do the best work possible with what was available. Of course, having lots of music on my shuffle helped enormously (and I could sing without annoying anyone).

The kinds of damage I encountered were the following: water stains, mold growth, warpage, media ‘bleeding,’ surface dirt, punctures and tears. I had blotters and sprayers to address the stains and warpage, erasers for the surface dirt and Japanese papers for mending. But the greater damage to all of these works was from previous matting and handling. Poor quality mats, extensive use of masking tape, notations in ball point pen (which bled terribly with moisture), and no knowledge of archival framing techniques had done far more harm to these pieces than the earthquake. That was a very disconcerting find; there was no familiarity with conservation or preservation. Proper storage and framing information was unavailable and good quality materials were scarce. None of these pieces would have suffered to the extent they did had they been appropriately matted and stored.

My work consisted of basic ‘triage’ for paper: dry cleaning of mold and dirt, removal of all tapes and hinges, discarding of acidic and mold-infested matting materials, humidification, flattening and repair to tears. All media was first tested, to determine degree of solubility; if possible, alcohol was sprayed on the front and back to deactivate mold spores and the art allowed to air-dry. When the media was stable, the art was washed in a ‘tray’ made of heavy Mylar stapled to form sides, and the object placed on a polyester sheet for support. Since there was no water filtration system, I used bottled drinking water modified with calcium hydroxide to adjust the pH.

A few drawings were damaged enough to warrant lining overall with Japanese paper. Wheat starch paste was cooked on a hot plate, and the lined drawings were stretched and dried on a Formica table top. Blotting paper was in very short supply, so it was rationed among the items to be addressed. Watercolors were lightly humidified with a sprayer and then weighted between polyester sheets and blotters under glass.

For additional weight, I ran up to the paintings lab and borrowed every heavy thing available (large containers of adhesive, etc.). It was basic and inventive at the same time; given the shortage of materials and the impulse to work quickly and efficiently, my colleague and I turned to one another for ideas, assistance and materials.

However, given the conditions outside of the Centre, we considered ourselves extremely fortunate to have electricity and running water. Food was ordered in, as we were not allowed to leave without our ‘guide’ (whose name was, truly, Mentor). In fact, security was so high that we were unable to  go anywhere on our own and thus the long workday was outlined in advance. After five days of intense work, the weekend arrived and we were confined to our house. The electricity went out and with it, the fans, the refrigerator and the lights. Only the gas stove still operated—but our food had spoiled with the heat! We shrugged and used our cell phone to call Mentor for a ride to the grocery store–again.

After nine days at the Centre, we wrote up condition and treatment reports on the completed artwork and lamented the fact that we had to leave. Both of us admittedly felt stymied in our inability to address all the pieces that needed some stabilization. At the same time, we were proud of what we had accomplished. There was the issue of not having access to specialized equipment that could have produced better results. A suction table, for example, would have helped with stain removal on water soluble items, and some hydrogen peroxide would have greatly reduced the more stubborn discolorations. But we were asked to stabilize these artworks and leave the ‘aesthetic integration’ to a later time. When I had the opportunity, however, I did use my watercolors to paint in small areas of missing pigment within the image, and filled some paper losses with toned Japanese mulberry of various thicknesses.

The program of deploying conservators has received enough funding to continue for another year. Part of the endeavor is to train Haitians in methods of art conservation, collections care and archival storage.

This is, of course, the most essential aspect of the recovery. I was asked if I wanted to return, and just this week agreed to do so. There is an almost endless amount of work to do and the country deserves all the aid and support it can get. It never felt dangerous and the people were wonderful. I can’t wait to return.


Published by The Gold Leaf: The Journal of the Hand Bookbinders of California, Spring 2011  

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Interview with Karen Zukor

Interview by Travistock Books, Alameda, CA

This week we welcome special guest Karen Zukor to our blog! Zukor is the senior conservator at Zukor Art Conservation. She’s been a professional paper conservator for more than thirty years and is a Fellow of the American Institute for Conservation. She’s been responsible for many collections, both public and private, trains both pre- and post-program interns, and offers lectures and workshops to the public. This week she was kind enough to sit down with us to discuss her career path, how conservation has evolved, and how rare book collectors can preserve and protect their collections.

Tav Books: You’ve been in conservation for over thirty years. How did you decide on this career?
Zukor: Initially I was teaching Art History on the East coast, but when I moved out to California in 1974 with my husband, I couldn’t find a teaching position. My interest in art & history also included a curiosity about materials and techniques, so conservation seemed like a good fit. However, I didn’t know really what it entailed or whether I’d have aptitude for it. So I apprenticed with two different conservators and took many courses in related fields. When those apprenticeships were over, I continued to work in the studio with the conservator who initially trained me; that was great because I always had a more senior person there to help me over rough spots. I opened my business four years after those apprenticeships began and worked out of his studio. Eventually, about two or three years later, I moved out on my own.

Tav Books: How have conservation techniques changed since you began your career?
Zukor: I would say that chemical research, particularly in paper conservation, has advanced quite a bit. We’ve gotten a lot more information about the processes that were in place for many decades and also potential treatments in the future. In some ways it’s been a subtractive rather than a cumulative process; long-term research has shown that many conservation techniques are simply not as successful as we’d like them to be–and in some ways can be detrimental. We know more, but we do less. The attitude has changed quite a bit.

Conservators these days are more conservative and practice more restraint. In this field, you’re always implementing some kind of intervention, no matter how subtle. But in the last 25 years, I’ve seen more conservators choose the most minimal treatment and opt for housing an object properly, to slow down the deterioration, rather than to reverse its damage. I think this is my approach, but we also do more full treatments. We have a great deal of experience, though! Right now about seventy percent of our projects are art on paper. The rest is archival material, manuscripts, maps, documents, and books.

Tav Books: Explain the differences among preservation, conservation, and restoration.
Zukor: Restoration usually involves removing as much of the damage as possible, returning the object to a condition that most closely resembles the way it looked when it was originally manufactured. When you conserve an item, you try to remove damage–ravages of time, stains and soil…but you acknowledge that the piece can really not be returned to its original appearance. The focus is instead on trying to stabilize the object both physically and chemically, while acknowledging that the object will continue to deteriorate. There’s less emphasis on cosmetic appearance.

Preservation is about finding the best long-term care and storage for an object, so that deterioration is minimal or at least slowed down as much as possible. When we preserve something, we often ask, “What kind of enclosure or package will give the most protection?” For a book, that would be a box–it keeps out light, dust, and should made out of good quality archival material.

The only times we do restoration is when we fill losses with paper that’s as close as possible to the original. If it’s not a terribly valuable object, we’ll draw in the missing portion or tone the paper. For preservation we sometimes do enclosures, especially boxes, for clients so that we know the piece will be properly housed for long-term storage.

Tav Books: What are the most common issues you address?
Zukor: We work on a lot of prints, drawings, and watercolors, and the most common problem is that they come in having been mounted to a board of poor quality. So they were either at some point glued down to a rigid support (because people always seem to think the piece looks better flat). Unless those supports are really good quality, they’ll transfer their properties to whatever’s attached–if you mount something onto an acidic board, that acidity will migrate to the piece. And you also change the nature of the piece; that print attached to a board is no longer a print; it’s a board with an image on it.

A second mistake we address on a regular basis is the use of pressure sensitive tapes. These are usually either used to make repairs or to attach a work of art to a mat. Paper conservation is relatively new. It’s only about sixty years old. And people only started studying paper chemistry and the factors that caused paper to deteriorate in the 1930′s and 1940′s. Research about pressure sensitive tapes is even more recent than that. And formulas for manufacture change periodically–masking tape from 50 years ago is a completely different product, so it will age differently than masking tape manufactured today.

Tav Books: What’s the most challenging or interesting project you’ve tackled?
Zukor: Oh, there are too many to single out! But probably the most challenging was a project in India with a very large, extremely damaged book, all hand written and illustrated in water-sensitive colors. The volume was close to 1,000 pages. It took three people six months, spread out over five years, to do the text. It was very difficult because we were working in an extremely remote location, so we had to bring everything we needed with us, which also led to some instances of interesting improvisation!

Tav Books: Any favorite materials to work with?
Zukor: The first thing that comes to mind is really Japanese papers. We do all of our repair, mending, and backing with very good quality Japanese papers because they’re thin, strong, and flexible. They are wonderful to work with. They’re much better quality than what we could get in the West. It’s pretty much all paper conservators work with. Most of them are handmade, and not dyed. They’re made of different kinds of fibers than they have here in the West. Japan makes the best paper without a doubt, and it’s certainly an arduous process. The conservation community has been partly responsible for keeping Japanese paper manufacture a viable craft.

Tav Books: Tell us a little bit about the kinds of works on paper that are most durable. What about the ones that are most delicate or fragile?
Zukor: Older papers are made from better quality fiber, such as cotton or linen. They also don’t contain a lot of additives or bleaches that would contribute to their deterioration. Later papers had sizings, bleaches, brighteners…all kinds of components that made paper less durable than the earlier ones. The absolute worst quality is newsprint, which is ground wood pulp.

Tav Books: To what extent does the material impact the way it should be stored and preserved? Zukor: The poorer quality the paper, the more likely it is to become brittle and darkened with exposure in just ordinary conditions. Pages made from low-quality paper need more protection from light, heat, humidity, and one another. They often need interleaving material. This can present a problem with antiquarian books, because you can’t interleave the entire book. That would put too much stress on the binding. But owners can definitely put acid-free tissue over the illustrations.

Tav Books: What’s the biggest mistake that private collectors make in caring for/storing their collections?
Zukor: Neglect. Not paying enough attention, not investing in the right materials, and ignoring the need to provide protection with the right kind of materials. Not only to slow aging in the individual item, but to protect different items from influencing and damaging one another. Collectors also tend to handle their items with less than very clean hands. I’m a hand washer because I think that white gloves, no matter how well fitted, give you a less secure grip on the item. There are some instances where gloves are imperative, but most of the time we recommend that people just wash really thoroughly.

The other thing I would emphasize is that collectors should not try to do their own repairs. If they don’t want to take something to a conservator, the best course of action is to leave the piece alone. Don’t attempt to do any repairs or add any material that you think will work! We spend a lot of time undoing work done by people with good intentions.