45th Annual Meeting – Photographic Materials Session, May 30, “The Re-creation and Conservation of Megalethoscope Slides” by Monique C. Fischer

Ms. Fischer’s talk focused on megalethoscope slides, an uncommon 19th century photographic process. When a group of these slides were brought to the Northeast Document Conservation Center (NEDCC) their conservation presented some challenges. Particularly, the lack of primary sources on the construction of the slides themselves. Further, the slides bridge conservation specialties, since they are comprised of albumen photographs on a wooden support. Ms. Fischer and her colleagues at NEDCC came up with some innovative treatment approaches to conserve these unique objects. Fischer underscored the collaborative nature of this project, which included FAIC, the George Eastman Museum, and numerous departments at NEDCC.

Megalethoscope slides are albumen prints mounted to a concave wooden support. Slides are placed into a viewer, which creates the illusion of depth and enlarges the image. The image can be lit from front (reflected) or back (transmitted) to create visual effects.

The first challenge of this treatment project was the lack of contemporary or historic information about the process. Fischer indicated one publication from 1999 that talked about the conservation of Megalethoscope slides and gave some helpful diagrams: Topics in Photographic Preservation 1999, Volume 8, Article 5 (pp. 23-30) “Megalethoscope Plates A Case Study: Conservation Treatment of Megalethoscope plates from the Collection of the ‘Museum for Art and History’ Brussels, Belgium” by Sylke Heylen and Herman Maes with supervision of Roger Kockaerts http://resources.conservation-us.org/pmgtopics/1999-volume-eight/08_05_Heylen.html

In order to learn more, Fischer worked with Mark Osterman, Photographic Process Historian at the George Eastman Museum (GEM). Todd Gustafson from the GEM also contributed because they have some megalethoscope viewers in the collection. Period megalethoscope slides at the GEM to were examined to extrapolate the process. Damaged slides proved to be the most useful for this, as they allowed for examination of the layers. The process Fischer described was complex. To summarize: They created albumen prints from digital negatives. The photographs were pierced from the front. The reverse of the print was painted with watercolor. A convex frame was made from bent pine. The photograph was attached to the frame using hide glue and then the edges were taped with black paper tape. Tissue paper was then added to the reverse. A dust cover was then added to the back of the slide.

Fischer showed a video of what it is like to view their re-created megalethoscope slide through the viewer. The scene began with reflected light, showing a landscape that was deceptively 3-dimensional. The light then transitioned to transmitted (behind the photograph), and the sun appeared to set in the scene and previously un-seen holes in the photograph created dramatic lights in a night scene. The effect is quite unique and certainly impressive.

The conservation treatment was designed to address the major condition issues: significant dirt, fly specks, tears and brittle dust covers with bug damage. The tear mending required some inventiveness because of the concave nature of the object and the layered structure. Fischer and other NEDCC conservators adapted a technique from Japanese panels in order to repair the tears. In this technique blotting paper supports are held in place with string to support the tear as it dries. After drying the string is cut. The dust covers were original, but highly damaged. A remoistenable lining was used to stabilize the dust cover, while minimizing moisture.

Finally, the inpainting of these photographs also presented challenges, since it had to be effective in both reflected and transmitted light. They mixed these two lighting techniques during inpainting.

In the question session following the talk, Fischer indicated that they used Gamblin Conservation Colors for inpainting because they were more translucent than watercolor. The book conservation department at NEDCC created custom phase boxes to house and protect the slides.

45th Annual Meeting – Photographic Materials Session, May 30, “Bellmer: Complexities of the Doll” by Krista Lough

Ms. Lough’s talk focused on Hans Bellmer’s Doll series of photographs. She gave some interesting background on Bellmer and her professed lifelong love of the artist was evident. As a fellow in photograph conservation at the Art Institute of Chicago, Lough’s work focused on the Art Institute’s newly-acquired doll print, which is a large print. She outlined some interesting discoveries about this print and found some parallels in other collections of Bellmer’s work. Her discussion of handcoloring, overall airbrushing, and mounting of the prints have obvious implications for conservators working with Bellmer photographs.

Hans Bellmer was a German professional working during the rise of the Nazi Party. He left his career in advertising as an act of rebellion in the 1930s because he didn’t want to (even indirectly) benefit the German state. He began a project with his brother to construct and photograph an artificial doll in 1933. Two additional dolls were constructed in 1935 (second doll) and 1937 (the Machine-Gunneress in a State of Grace). The dolls were posed in provocative and intentionally perverse positions and then photographed. The dolls seemed to get more abstract, with multiple sets of breasts, legs, pelvises, and torsos. They were made primarily of tissue paper and glue.

Bellmer made both small format photographs and larger prints. In particular, a set of hand-colored small prints was created for a book “Les Jeux de la Poupee” created with the surrealist poet Paul Éluard. He made some larger prints, about 26 inches square, at this time of the same images. The Art Institute’s print is a large print of an image from this book. In the course of Lough’s study, she found that the larger print did not precisely relate to the copy in the book, implying that he was working from multiple negatives and making specific decisions unique to each print. Lough stressed that he was treating each print as a unique work of art, not trying to replicate the same appearance in all prints of the same image.

The Art Institute’s print had some interesting overpainting, including an overall layer of dark airbrushing that was difficult to see without magnification. This layer appears to have an overall darkening effect on the print. There was also extensive applications of gouache and dyes. When Lough compared this print to other large doll prints, she found no rigid working method that Bellmer applied to all the prints. Again, they appear to have been treated uniquely.

When considering treatment of the Art Institute’s print, Lough encountered some obstacles unique to Bellmer’s working method. The treatment was designed to address issues with grime, losses and chipping in the media. Through extensive testing she found that the print could not be safely surface cleaned. Traditional cleaning solutions such as water/ethanol removed retouching. Ethanol alone caused changes to the surface sheen (perhaps indicating a coating? Samples were taken for testing). Even dry cleaning was ruled out because the abrasive action reduced the topography of the gouache. This meant that the treatment was limited to tear repair.

In summary, Lough emphasized that Bellmer’s Doll photographs should be treated as unique and distinct objects with very real conservation challenges.

45th Annual Meeting – Paintings Session, 1 June, “Color Field Paintings and Sun-Bleaching: An approach for removing stains in unprimed canvas” by Jay Krueger

Jay Krueger’s talk was a great synthesis of the most interesting and exciting ideas running through this year’s conference: interdisciplinary collaboration, a thoughtful and considered approach to complicated and seemingly radical (but necessary treatments), and recognition of the fact that well-intentioned traditional attempts to minimize or limit treatment can cause unintended secondary damage. The talk focused on the National Gallery of Art’s treatment of Morris Louis’ 133, painted in 1972.

Color field painting, as exemplified here in Louis’ work, focuses on areas of pure color, and its abstracted forms are freed from the constraints of representation, brushwork, etc. Unlike traditional paintings with distinct layers of canvas, ground, paint, etc. the direct application of (sometimes thinned) paint to unprimed canvas allowed the paint to soak into the canvas support, staining it rather than sitting on its surface.  The unprimed canvas is integral to the composition: its flat, unbroken expanse of color (i.e. the material itself) and relationship to the paint is essential, and any disruption of this is as detrimental to the work as damage to the paint layer would be.  The painting was already described as having a “smudge” on the canvas when it entered the Gallery’s collection in 1976, and its condition had not improved over time, despite attempts at locally treating damages and defects in the canvas.  By 2007 the stain was so pronounced, and other areas of staining had developed to such a degree, that the painting was suggested as a suitable candidate for more significant treatment.

It was at this point that the NGA felt comfortable enough to consider putting into practice a methodology they have now spent twenty years investigating and testing, and which I found to be the most inspiring part of the talk. Their proposed treatment embraced the rejection of three principles generally regarded as law in paintings conservation: don’t put your paintings in direct sunlight, don’t expose them to water, and limit your interventions to the minimum level of what is necessary to treat areas of damage.  The NGA quite rightly recognized that for these specific conservation concerns, paintings conservation could gain from consulting and borrowing from our colleagues in paper conservation by approaching the treatment of canvas supports in the same ways that paper conservators treat their cellulose-based supports.  They also brought the Getty onboard, since their history of using scientific research to inform and support treatment made them the ideal partner for investigating the material aspects of the painting, necessary vs. superfluous components of various treatment steps, and the longterm success and effects of the treatment itself.  The Getty’s spacious private terraces and steady supply of California sunshine also proved to be very beneficial!

I will leave the details of the treatment to be more rightly and thoroughly covered in Krueger’s contributions to the postprints, but the essential process is an adaptation of the aqueous sun-bleaching technique used in paper conservation. The painting (mounted to a working strainer) is positioned on an incline, completely dampened and held in a steady flow of water, in full sun.  By treating the canvas as the homogenous material it is, you avoid the problems of trying to control the movement and activity of water as applied locally, and instead appropriate and better exploit those same properties to our (and the painting’s) benefit.

Significantly, the extraordinarily successful treatment uncovered secondary damage caused by those previous localized attempts at canvas cleaning/stain reduction: after aqueous sun-bleaching (which in and of itself could not overclean the canvas), these were visible as noticeably lighter patches of canvas which then had to be toned back. Additionally, the project included investigation of whether the treatment had material as well as aesthetic benefits.  Paper conservators report that paper supports are stronger after washing, and there was some thought that washed canvases could show similar improvement.  Alan Phenix ran tensile strength and color change tests on canvas after washing and sun-bleaching.   The canvas did show some improvement in strength, and both washing and sun-bleaching helped prolong the life of the canvas by removing damaging degradation products.

Krueger’s talk forms a natural trio with two others given at this year’s conference: Maggie Barkovic and Olympia Diamond’s “Pioneering Solutions for Treating Water Stains on Acrylic Paintings: Case Study of Composition, 1963, by Justin Knowles” and Jonathan Ashley-Smith’s “What’s so ethical about doing nothing?”.  Barkovic and Diamond’s presentation highlighted their successful treatment of a similarly damaged painting using a modified agar gel, and their different approach emphasizes (as Krueger himself did) that aqueous sunbleaching is not suitable for all paintings (the Knowles’ canvas is sized, unlike Louis’ 133).  Ashley-Smith’s provoking contemplation of the future of conservation elegantly pointed out that an overemphasis on minimal intervention can, and has had, unintended consequences; one of these is unknowingly damaging the pieces themselves.  By being so risk averse as to avoid treatments that seem unnecessarily invasive, are we in fact contributing to the degradation of the works we are charged to care for?  Although the pendulum swing towards minimal intervention and preventive conservation is understandable, these talks serve as a valuable reminder to continue to explore new treatment methodologies supported by our increasing wealth of collaborative knowledge and technical advancement.

45th Annual Meeting – Paintings Specialty Session, June 1, “The Conservation of Alexander Calder’s Last Work Mexico #3: The cross-disciplinary treatment supported by SEM and TEM paint cross section analysis using focus ion beam (FIB) sample preparation,” by Sara Wohler and Ralph Weigandt

Author Sara Wohler discussed the fascinating history of Alexander Calder’s airplane model, Mexico #3, the last work he completed before his death, and then presented the conservation treatment of the model. Author Ralph Weigandt then discussed the technical analysis of the paint film on the airplane.  This presentation served as a fun continuation of the painted airplane theme, following Lauren Horelick’s May 30th talk “When an Airplane Acts like a Painting: Applying Established Conservation Methodologies to Ephemeral Aircraft Materials.”


Wohler described the beginning of Alexander Calder’s airplane-making career: In 1972, New York advertiser George Gordon approached Calder with the idea of painting an full-scale airplane.  Calder loved the idea, as it would combined his experience in kinetic art and his background in engineering.  Gordon paired Calder with Braniff International Airways, and Calder created the designs for two airplanes: Flying Colors of South America and Flying Colors of the United States. These were both tremendous public successes.

^Braniff International Airways employee ceremony, 1975, with Flying Colors of the United States.

The author then described the process in which Calder painted the planes: He began by experimenting with designs on several 1/25-scale Westway Aircraft Models.  The chosen design from the model was then scaled up using graph paper that was attached to the full-size airplane.  Calder and his team then used pounce wheels to poke holes through the design on the graph paper, and black spray paint was applied through the pounce holes.  The graph paper was removed, and the paint colors were spray applied by a Braniff team.  Calder supervised the entire process, and hand-painted the engine necelles during the spray process.

Then the author described the artistic process for the model Mexico #3. In 1976, Braniff commissioned a third plane from Calder, this one to celebrate the great relationship between the U.S. and Mexico.  The author provided amazing historic film footage of Calder painting the Mexico #3 model plane.  She noted that the plane itself was made of fiberglass, and Calder created his design using gouache. On November 11, 1976, Calder completed and signed the work, and tragically, passed away later that evening.  Although the design was completed, Mexico #3 was not transferred to an airplane, as Calder was no longer alive to approve of the final result.

^Calder painting the Mexico #3 model.


The model airplane was brought to Kuneij Berry Associates, Chicago, for conservation treatment. Through examination, the author found that the fiberglass model airplane had two priming layers, blue and grey, and a final, even, white coating. Calder painted onto the proprietary white surface using gouache, possibly that he made himself. While the airplane was quite dirty and structurally had sustained a few losses, the treatment was relatively straightforward.

The plane was in poor aesthetic condition; it had previously been displayed in a planter with dirt and plants around it, exposing it to both dirt and moisture. Fortunately, the gouache paint layer was generally in good condition and intact, aside from a few abrasions.  The synthetic varnish layer, which had protected the gouache layer, was covered in surface dirt and grime.  The plane was first surface cleaned with deionized water and PVOH sponges, but a lot of the dirt remained embedded in the varnish.  The synthetic varnish was removed with aromatic solvents.  Care was taken to only thin the varnish on top of the gouache paints, as the paints were sensitive to aromatic solvents.

^Detail of the varnish removal, cleaned (left) and with remaining varnish (right).

Structurally, the plane had suffered a few chips to its wings and there were a few areas of flaking paint. The flaking paint was consolidated with Paraloid B72. To recreate the tips of the wings that had been chipped away, molds were made of Elastosil M4600 A/B and cast using Milliputti. The cast pieces were sanded and adhered to the wings using Paraloid B72.

Shallow losses in the white priming layer were filled and inpainted simultaneously with Golden MSA colors. Losses in the gouache colors were then inpainted with QoR watercolors.  The model was then sprayed with a few, light, protective layers of RegalRez 1094. After the successful treatment, it was recommended that the painting be displayed in a new, more environmentally stable location.

^Sara Wohler inpainting Mexico #3.

Technical Analysis

The technical analysis of Calder’s gouache paint was carried out by Ralph Weigandt, who is currently the primary researcher on the collaborative National Science Foundation (NSF-SCIART) grant with the University of Rochester’s Integrated Nanotechnology Center to advance the scientific understanding and preservation of daguerreotypes. The authors carried out technical analysis of the gouache paint in order to better understand Calder’s materials and techniques, potentially inform the conservation treatment, and to pioneer the use of Focus Ion Beam (FIB) milling for SEM-EDX analysis and PLM examination on paint films.  Through Transmission Electron Microscopy, SEM-FIB allows for the elemental analysis of paint layers at the nanometer scale!

Weigandt explained in depth about the sample preparation process, the Focus Ion Beam milling of the larger sample into the much smaller (~12 um x 0.5 um) cross-section, the comparison between traditional SEM-EDX spectroscopic elemental analysis and mapping vs. the Transmission Electron Microscopy and associated SEM-EDX elemental analysis and mapping capabilities.  In essence, the FIB milling and TEM allows for highly precise, high resolution elemental analysis and mapping, allowing scientists and conservators to see the inorganic composition of individual pigment particles.  A poster from University of Rochester graduate student So Youn Kim outlines the project with excellent photographs and illustrations.

In the end, the elemental analysis did not contribute greatly to the decision-making process of the treatment, but did provide excellent information about Calder’s painting techniques and materials for Mexico #3, which can inform a discussion about his art-making process for this piece and his art in general.  It is clear that this Focus Ion Beam technique coupled with Transmission Electron Microscopy and SEM-EDX elemental analysis is an exciting analytical technique that will be extremely useful in the precise identification of inorganic pigments, fillers, etc., in paint films. Furthermore, it is great to see yet another example of private conservators working with scientific departments at universities (or elsewhere) to investigate materials of cultural heritage objects!

45th Annual Meeting – Paintings + Research & Technical Studies, May 30, “Pioneering Solutions for Treating Water Stains on Acrylic Paintings: Case Study of Composition, 1963, by Justin Knowles” by Maggie Barkovic and Olympia Diamond

Maggie Barkovic and Olympia Diamond presented a case study that outlined the decision-making process that lead to the successful treatment of darkened, dirt-infused water stains on the bare canvas portion of a large-scale acrylic dispersion painting: Composition, 1963, by Justin Knowles.  The authors attributed the treatment’s success to the combination of extensive evaluation of Knowles’ materials and aesthetic aims and the understanding of new, innovative cleaning techniques designed for acrylic dispersion paintings (with the help of Brownyn Ormsby, TATE, and Maureen Cross, Courtauld Institute of Art).  This presentation served an excellent compliment to Jay Kruger’s presentation Color Field Paintings and Sun-Bleaching: An approach for removing stains in unprimed canvas, which discussed the treatment of acrylic solution and oil paintings on bare canvas.

Composition is a privately-owned work that was brought to the Conservation and Technology Department at the Courtauld Institute of Art for treatment in 2013.  The large-format work is a two-dimensional acrylic painting with brightly colored geometric forms juxtaposed against an unpigmented acrylic sized canvas.  The painting had sustained disfiguring water stains along the top and bottom edges which disrupted the aesthetic reading of the image, rendering it unexhibitable.


In the first step of the conservation process, Barkovic and Diamond assessed how the water stain affected the aesthetic interpretation of the painting.  They explored where this painting fit into the artist’s oeuvre: it was part of a series of early, pivotal works where Knowles explored his initial ideas of spatial tension using non-illusionistic geometric compositions that incorporate negative space in the form of unpainted canvas. The authors carried out technical examinations of four other paintings from this early stage in his career, finding that Composition was painted in a comparable manner to his other early works: a fine linen canvas was stretched on a wooden stretcher and then sized with an unpigmented (pEA/MMA) acrylic dispersion coating.  Then, Knowles used pencil and pressure-sensitive tape to demarcate where he would paint the geometric forms with acrylic dispersion paints.  Though he applied a transparent acrylic “size” layer over the linen/negative space, he still considered the visible canvas “raw” and unprimed. Through the examinations and research on Justin Knowles’ personal notes, the authors assessed that the characteristics and color of the linen canvas were equally important to the interpretation of the work as the paint colors.  As such, the canvas should be treated and the water stains removed if at all possible.


Second, the authors explained that they needed to identify the components of the water stain (with no prior knowledge of water-staining incident) in order to test cleaning methods.  Replicas were made using linen and the same unpigmented acrylic polymer that Knowles most likely used. The replicas were then stained with dirty water. Using XRF spectroscopy and empirical testing as a guide, a visually accurate and equally tenacious water stain was made with iron, calcium, and organic “dirt” components from aged linen.  The test replicas were aged in a light box for two years to allow the stain to photo-oxidize and bond with the fabric and size layers.


Third, the authors needed to determine how to treat the water stain with the presence of the unpigmented acrylic dispersion size layer, which swelled in water and was affected using polar solvents. Their goal was to remove the stain or reduce the appearance of the stain to make successful inpainting possible.  The authors looked to successful textile and paper conservation treatments for possible methods.  The initial cleaning and/or retouching tests included the use of solutions with various pH values, conductivities, chelating agents, surfactants, bleach (sodium borohydride), the application of toasted cellulose powder, and pastel retouching.

The authors thoroughly explained the various test groups, but a recapitulation of all of these various solutions is outside of the scope of this blog post.  In general, higher pH values (around 8) and higher conductivity values (above 2.5 uS) allowed for better cleaning efficacy.  Perhaps more notably, the chelating agent DTPA (diethylene triamine pentaacetic acid) greatly outperformed TAC in cleaning efficacy.  This is likely because DPTA is a much stronger chelator that is much more suitable for sequestering iron and calcium (which XRF showed to be present in the stain).  DPTA could be used safely because the acrylic size layer was unpigmented.  Finally, the use of agar (rather than free solution) was found to be useful in the reduction of the stain.  The agar gel allowed for greater control of the solution distribution onto the stain and dirt absorption into the gel.  The most effective cleaning agent, which was eventually used to clean the painting, was made from a higher concentration of agar gel at 5% (w/v), using Boric Acid 0.5% (w/v), DTPA 0.5% (w/v), TEA, at pH 8, 2.4 mS.

Evaluation of Successful Treatment

While a successful treatment methodology was developed through empirical testing, an investigation into the effects on the surface morphology of an unpigmented acrylic dispersion size layer was thought necessary due to the different absorbencies among the test canvases, observed differences in retention times for the agar gel, and concerns about the higher pH required to reduce the stain.  The lack of pigmentation and hard surface features made changes caused by cleaning more difficult to perceive, measure and contextualize, so changes in surface gloss and stain reduction were evaluated with a spectrophotometer and subjective observations by conservators. The impact of the cleaning methodology on the surface of the size layer and canvas fibers were examined with dynamic Atomic Force Microscopy (AFM) and high resolution digital microscopy. A preliminary investigation into possible residues from cleaning was also investigated using FTIR-ATR spectroscopy.

The number of samples for AFM was too small to draw concrete conclusions without more testing and utilizing additional analysis such as FTIR-ATR; however, a general trend was observed that an increase in the gel concentration from 2.5% (w/v) to 5% (w/v) appeared to reduce the time in which fiber flattening occurred.  In addition, FTIR-ATR showed a decrease or complete removal of migrated surfactant from the acrylic size layer surface in all treated samples regardless of the agar concentration in the gel, and along with the swelling of the acrylic layer, was considered by the authors an acceptable risk with this treatment.  IR bands corresponding to agar or the additives  in the cleaning solutions were not detected.

Final Treatment

As mentioned previously, the cleaning agent that was eventually used to clean the painting was made from a higher concentration of agar gel at 5% (w/v), using Boric Acid 0.5% (w/v), DTPA 0.5% (w/v), TEA, at pH 8, 2.4 mS. The agar was hand-cut to perfectly align with the stain patterns on the canvas and weighted with sandbags to increase the gel-canvas contact.  Using this method, stains were greatly reduced.  However, a few, minor discolorations remained after the cleaning.  Further tests were carried out to determine the best inpainting method for these residual discolorations. Dry pigment with Lascaux Jun Funori, Aquazol 50, Aquazol 200,  watercolour and gum arabic and Paraloid B72 were all tested for optical effects, handling properties, and reversibility. The Aquazol 50 series was found to be the most effective overall and was used to inpaint the remaining discolorations.


The authors concluded by restating that the success of the treatment would not have been possible without the combination of art historical and material understanding of Knowles’ work and research into new cleaning methodologies for acrylic dispersion paint films.  They thanked their project advisors Maureen Cross, Courtauld Institute, and Bronwyn Ormsby, Tate, and many others for their generous support and guidance throughout the project.


45th Annual Meeting, Objects, “The Treatment of Two Terracotta Architectural Reliefs by Andrea della Robbia at the Metropolitan Museum of Art,” presented by Carolyn Riccardelli

This is a joint paper by two objects conservators at the Metropolitan Museum of Art, Carolyn Riccardelli and Wendy Walker. Along with many others at this conference, the topic of this paper concerns treatment and installation considerations of Renaissance-period glazed terracotta from the della Robbia workshop. This paper discusses two masterpieces by Andrea della Robbia (1435-1523), both pretty dramatic in their scope of treatment.

The first, a lunette of Saint Michael the Archangel, starts with a tragedy. In 2008, it came crashing to the floor from over a doorway in the 15th Century galleries where it had hung on display at the Met since 1996. If you search online, you can find articles about that event, but I will not link to any of them here. What I will link to, however, is the press release from April of last year, announcing that the lunette is restored and back on view.

Riccardelli presents the treatment that took place over eight years, a massive undertaking mainly overseen by Walker. She describes how it offered the conservators a rare peak into the working methods of della Robbia. For example, they could see in a more intimate way exactly how the clay used to mold the lunette was wedged (not very well at all), which tells us that the makers must have understood their clay so well to know this step wasn’t necessary. They also found evidence of tool marks and fingermarks – yes, even fingerprints! – from pressing the clay into the molds. The paper outlines the treatment of this work, which includes the use of the “Tulio blend” (3:1 B-72/B-48N in acetone with 6% ethanol) as the main adhesive, and a mount that incorporates brass clips to hold the panels to an aluminum backing panel. We are all left with beautiful after-treatment images of the lunette and a happy ending to the story.

The second della Robbia piece presented, a massive tondo of Prudence, starts with an exhibition announcement at the Museum of Fine Arts, Boston, Della Robbia:  Sculpting with Color in Renaissance FlorenceAlong with pieces from Italy never seen in the United States before, as well as loans from the Brooklyn Museum and the Los Angeles County Museum of Art, the Met’s Prudence was featured.

Riccardelli presents the conservation efforts to get Prudence ready for loan and exhibition, having one year to do it. The piece consists of 16 molded and modeled sections – a central tondo surrounded by a colorful garland – and nearly every piece had old restorations that needed to be addressed. This included an unstable mount. Their paper outlines the treatment steps taken, including cleaning and restoration removal (steam, solvent, mechanical), and a well-engineered mounting system that employs carbon fiber clips and straps, and a honeycomb aluminum backing panel. (More details about the use of carbon fiber clips in this treatment are presented in Riccardelli’s other paper during this conference, “Carbon Fiber Fabric and its Potential for Use in Objects Conservation.”)

It was during the cleaning phases that the conservators again made an exciting discovery, uncovering original markings and finger impressions that clearly indicate the proper order of the garland border pieces. More than this, the pre-treatment arrangement of the garland was incorrect! Their paper shows the dramatic shift from the previous arrangement to the corrected one, totally altering the feel of the piece and giving one the satisfaction of being able to return something home to its rightful place.

45th Annual Meeting – Electronic Media Session, June 1st “The David Wojnarowicz Knowledge Base: A Wiki-based Solution for Conservation and Exhibition Documentation” by Glenn Wharton and Denna Engel

The initiative

Glenn Wharton, Clinical Associate Professor in Museum Studies at New York University, started the talk by the initial following challenge: how to organize and access the data created by time based media conservators during the treatment process of a contemporary artwork? Based on the MediaWiki platform, this project ended up dealing with larger issues met in time-based media conservation.

Conservation Documentation

Conservators create a lot of documentation, in various formats (notes, videos, drawings, etc.) and one problem is how to organize this information and make it available within an institution. Also, as Wharton mentioned, at the New York University, teachers tend to help and encourage students to work and experiment with different programs.

The David Wojnarowicz Knowledge Base

Wharton followed by introducing David Wojnarowicz, an artist and activist who died of AIDS in 1992, who produced, among other materials, paintings, drawings, and videos. His archives left at NYU were the primary sources of information – a page of his journal was shown as an example. In order to complete these precious resources, the students interviewed several persons who worked with the artist, and a computer scientist did technical research on the tools he would have used.

As Wojnarowicz is getting more and more attention internationally today, people worry about how to preserve and exhibit his work. In that regard, the idea was to gather more information available for researchers, curators and conservators. One challenge was to document his “Magic Bow”, found under his bed and containing objects related to several of his artworks. The question here was how to report the very complex relationship between those elements and the actual artwork pieces using a searchable database.

The project goals and system requirements

Deena Engel, Clinical Professor in the Department of Computer Science at the Courant Institute of Mathematical Sciences of New York University, presented the goals to be reached by the future database. The idea was, along with conservator students, to think through the approach of the software development, in particular, how to capture the complex relationships between the different elements, with an easy to use interface, and a long term preservation of the data.

In order to select a suitable software, they established the requirements for the future database as follow:

  • Be a support for a directed graph model;
  • Support user authentication;
  • Be an open source software:
  • Require only standard maintenance;
  • Support extensive discoverability for all;
  • Have a clear navigation;
  • Support controlled vocabularies.

In the lab: Software testing

The students used the data collected early to test different softwares – such as Omeka, Drupal, Plone, Collection Space and WordPress. After a lot of searches, they chose the MediaWiki, an open-source software with a strong user community, easy to use and configure, which supports text, image, audio and video medias, allowing for example to publish conservation reports and audio interviews, and filled their technical needs – In particular, they wanted the pages to be available on all types of supports (phones, tablets, etc.).


The content was organized in categories and subcategories; for example the category “Works on Paper” was subdivided in “Drawings”, “Prints”, “Stencils” and “Xeroxes”. The different pages related to each other are connected via hyperlinks; furthermore, the “what links here?” part allows to reach the pages that lead to the current page.

Launching of the database

A Beta Test Session was organized with the NYU students, conservators and archivists, were questions were asked, in particular about the user interface, the user experience and the scholarly goals that had to be reached.

On April 21, 2017, a Symposium about David Wojnariwicz’s work was organized at the Fales Library & Special Collections, New York University, were the database was presented and launched.

Though, the project is not over! This is an ongoing research, and anyone can contribute by sending pieces of information to: fales.wojnarowicz@nyu.edu.

For the future, the scholars at New York University are interested in working with museum professionals on similar projects, using MediaWiki again or other software – Deena Engel mentioned that she would prefer to experiment with other tools.

This presentation allowed to appreciate the common effort made by scholars, archivists and art historians, as well as computer scientists and curators, in order to make available qualitative information about a contemporary artist’s complex work, in an accessible and intelligent form. Glenn Wharton added that university was a great place for that kind of research, because of the possibility to get research grants, the available time and the deep interest and motivation of the students.


The David Wojnarowicz Knowledge Base: http://cs.nyu.edu/ArtistArchives/KnowledgeBase/index.php/Main_Page

Presentation of the Artist Archives project: http://nyuhumanities.org/the-artist-archives-project/

The Artist Archive Initiative: http://cs.nyu.edu/ArtistArchives/Initiative/


AIC’s 45th Annual Meeting – Book & Paper + Research & Technical Studies group talks, May 31, 2017 – “Centuries of Cellulose: Lessons Learned from the Molecular Size of Cellulose in Naturally-Aged Paper Collections” by Dr. Andrew Davis


Andrew began his talk by very graciously acknowledging that many other people have contributed data that informed his paper. Andrew’s work is based on research began by William Barrow, a paper chemist at the Library of Congress until the 1960’s. Barrow’s research on books tried to draw a connection between physical properties and chemical content. He had collected about 1000 books published between 1500 and the 19th century, and he took various measurements such as fold endurance, pH, alum content, etc. He tried to draw connections between those sets of data to predict the ageing characteristics of the paper. This collection was obtained by LoC in the 1970s, and are still used for destructive testing today. But where Barrow used macro and micro scale measurements, Andrew looks to the middle ground: polymer chemistry. For that, he uses size exclusion chromatography, or SEC.

SEC measures the degree of polymerization of cellulose using a roughly 1mm squared sample size. (It may be helpful to think of degree of polymerization as the molecular weight.) The degree of polymerization of a sample can be compared to known references. It should also be noted that papers have a mixture of molecules of different sizes, and SEC provides a distribution curve. The more large molecules in a sample, the less degraded the cellulose, meaning that the paper is in better condition. Andrew discussed several examples of treatments of iron gall ink on paper where SEC was used to show the effects of those treatments on the papers.

Barrow’s research indicated that pH was the best indication of the future physical properties of paper. Andrew took about 80 samples from Barrow’s collection and confirmed that the molecular weights of paper correlate with pH (when the pH drops, the molecular weight drops). Andrew then looked to see if the molecular weight corresponded to physical properties; with newer papers, the molecular weight does tend to be smaller. Poor tear resistance also corresponds to low molecular weight. In general, he found that the molecular weight determined by SEC is a better indicator than pH for future physical properties for both newer and older books.

SEC certainly has advantages. The sample size is ridiculously small. Tells you about the physical building blocks of the paper, giving a better idea of what’s in it and what state the cellulose is in. There are some disadvantages to overcome before this technique is in every lab. The test itself takes a week to do. It requires extremely expensive equipment and organic solvents, and one must have the technical knowledge to interpret the data. Andrew’s ultimate goal is to turn this into a rapid technique that’s affordable, so that the molecular weight distributions of an object can be included in an object’s record and be pulled up by a barcode. That’s an exciting prospect!

Andrew’s work presents a very interesting analytical option that future conservators might have access to. It would be nice to have a predicting model for the degradation of library objects. But it would be even more interesting to see the effects of treatment on paper. It is important that conservators continue to check our own work, and I’m glad to have assistance with that from scientists like Andrew.

AIC’s 45th Annual Meeting – Book & Paper + Research & Technical Studies group talks, May 31, 2017 – “Revisiting paper pH determination: 40 years of evolving practice in the Library of Congress Preservation Research and Testing Laboratory” by Cindy Connelly Ryan

Cindy’s talk was a mightily condensed summary a few of the techniques for measuring the pH of paper that the Preservation Research and Testing Division (PRTD) at the Library of Congress has investigated over the last 4 decades. Her introduction was a summary of the challenges presented by this task. Due to the chemical structure of cellulose and the nature of paper, most methods can only approximate the pH of paper. The method of sample preparation can impact the results of measuring. How paper ages means that there may be a different pH in different regions. The ions that dictate the pH may not be soluble in water, making measuring pH harder. And atmospheric carbon dioxide can react with your solution and affect your results. Notice that I said “solution.” Cindy ended her introduction by noting that you can’t measure the pH of a solid. But you can approximate it, and the PRTD has been trying to identify the best way to do this for decades.

The PRTD’s focus on the pH of paper began in 1971 with the deacidification program. Chemist George B. Kelly used titrated alkalinity and titrated acidity as an “external yardstick”, and four different extraction methods: TAPPI cold method, TAPPI hot method, surface pH measurement, and “pulped” pH method. Kelly determined that for acidic papers, the method of measuring pH didn’t matter much, but the alkaline papers had an acidic pH despite their 1% alkaline reserve. The hot extraction method was shown to be much more accurate with alkaline papers, as it was likely better at getting all the ions into solution. The pulp method came close. Cindy then went on to talk about the uncertain origins of the pulp method (i.e. it’s not discussed in any published literature, but is mentioned frequently in internal documents from the PRTD). (I do wish that Cindy had gone into detail about the process of each method of extraction, because I wasn’t too sure about how each process worked. She doesn’t mention pH strips, gels, or pH meters at all in this talk. And TAPPI stands for the Technical Association of the Pulp and Paper Industry.)

Then Cindy skipped to the late 1990’s (she does mention that a few papers had been published in the decades between). By this time, the PRTD ramps up its documentation efforts, as well as its protocols for sample collection and homogenization. Most of these protocols were put on their website. During the renovation of the instrumental suite in 2007, the lab’s emphasis shifted to developing non-destructive and micro-invasive techniques, which were more appropriate for art objects rather than circulating collections materials. This meant that the sampling methods had to adjust accordingly.

To address the new challenge of micro samples (or none at all), the PRTD tried to make surface pH measurement work, but found that tideline formation and sensitive media made that difficult. “Miniaturization” was another method the PRTD tried. For this technique, sample size can be a few milligrams to a few micrograms, depending on the paper to water ratio and other details of sample preparation. They found that slurrying helps, but filtration makes no difference in pH measurement.  In addition, controlling the amount of carbon dioxide was key to getting an accurate reading with acidic papers. Both purged bags and sealed vials were tried, with comparable standard deviations but slightly different pH readings. The pH readings from the micro methods agreed fairly well with macro methods.

One of the best takeaways from Cindy’s talk was when she shared that during their renovation, the PRTD was sending out samples to a contractor for pH measurement, and papers that had an alkaline reserve were coming back with an acidic pH. Their conclusion was that not every method is appropriate for every type of paper, and that sample preparation can also affect results.

Here were some tips about each of the methods, taken from Cindy’s recap slide: The Hot Method is closest to objective measurement, but takes two hours per sample. The Pulped/Blender method generally agrees with the hot method, but is faster. The ISO cold method has a much higher standard deviation than the TAPPI cold method. Thea Surface pH method has the highest standard deviation of any method tested, and is difficult with alkaline papers, thick boards, and boards with adhesives. This method also causes tidelines. And the Mini Method is also difficult with thick boards, but the results comparable in repeatability to large scale extraction methods.

So, what does it take to accurately measure the pH of a piece of paper? A focus on repeatability and an optimistic attitude! The scientists and preservation specialists at the PRTD struggle with many of the same challenges that the rest of us do, albeit with fancier equipment. It sounds like just getting a ballpark figure for pH is as close as we can hope for for now. The PRTD is still investigating methods, and we should all look forward to their results!

Finally, one cool tip: You can make your own micro blender with a homemade Mylar blade attached to a Dremel tool!

45th Annual Meeting, Electronic Media, “The Ballad of Little Bill: Collaboration in Time-Based Media Conservation,” Ariel O’Connor and Daniel Finn

In the abstract for their paper, Ariel O’Connor, Smithsonian American Art Museum (SAAM) objects conservator, and Dan Finn, SAAM media conservator, write that this presentation “aims to present a case study that is exemplary of the wide range of expertise that time-based media conservation can require, and the collaborative approach that it necessitates.” Their talk certainly demonstrates this, as it presents a myriad of challenges, from documentation tasks and working with living artists, to what to do when a massive cable failure occurs just minutes before the museum director is coming to see the work in action.

The paper discusses the kinetic sculpture titled “the willful marionette,” by Brooklyn-based artists Lilla LoCurto and Bill Outcault, and the piece incorporates sculpture (a 3-D printed, blue poly(lactic acid) biodegradable plastic marionette with strings made of fishing line), software (Puppet Master), and electronics. The custom software is designed to interact with its audience, responding in real time to recognizable human gestures with gestures of its own. Meet the artists and get a glimpse of the marionette, affectionately named Little Bill, in this short video.

O’Connor and Finn outline the documentation process they employ at SAAM, making us all realize how incredibly detail-oriented the documentation of time-based media works really needs to be. This includes a testing and acceptance report, an identity report, various iteration reports, documentation photographs, artist interviews, copious notes, and organization and storage of all files, such as the STL files that can be used to reprint the sculpture in the future, if need be.

The authors candidly recount stories about working with this exciting and challenging piece and getting it ready for the museum director to review. For instance, an issue with Little Bill not blinking properly was fixed by the good old “CTRL-ALT-DEL” method. But when the 80-lb. line that mainly held up the sculpture spontaneously snapped, they had to be resourceful and quick-on-their feet, looking to the facilities crew for the right tools needed to remedy the situation.

Future challenges for this work are similar to many time-based media works, including what will happen to the proprietary software that Little Bill is operated on, as well as storage considerations for the plastic sculpture itself.