42nd Annual Meeting — Collection Care + HVAC Session, May 31, 2014, “Sustaining Collections: Putting Theory into Practice” with James Reilly, Lois Price, John Castle, Tom Sherwood, Don K. Rowe

I was tweeting up a storm during this session (#AICSF).  Why the fervor? There is nothing like hearing the conversion of smart professionals towards the gospel of collaboration, preservation management and the preservation environment.  A two-year intensive review of the air handling systems at the Winterthur Museum, Garden & Library (Delaware) generated insights into the management of the preservation environment that provided refreshing new data on how to approach mechanical renovation projects.  During the panel, each stakeholder told a part of a story that provided many “Ah Ha” moments. Here’s a sample of the tweets:
On the issue of getting all the stakeholders in the room:
I keep saying this: collaboration between facilities and conservation colleagues is a key for establishing set points.
Collections management and facilities management must be in handshake [pic of hands shaking].
On the implementation of nightly shut downs and seasonable shifts to manage the preservation environment and reduce the use of water and energy:
It’s not so simple to do shut downs and seasonably adjust set points.
Achilles heel of doing shut downs may be antiquated systems including [antiquated] monitoring.  Really, you cannot just shut off the furnace!
On the struggle to adequately understand the way that air handling systems may have evolved over time due to changes in personnel, changes in technology, and changes in the built environment:
Sounds like facilities engineers could take a page out of @conservators documentation strategies and requirements.  #asbuiltsnotdrawn
[A fireplace that had served as an air return decades ago was blocked during renovations wreaking havoc on the HVAC control]: Secret air return: non-working fireplace… blocked.
[Retired engineer returns to review the system and finds out that all of the built-in compensation for Gerry-rigged HVAC has been resolved]: “We always run two boilers!” “Let me tell you what: now we’re only running one.”
On the monitoring tools that are essential for understanding how your systems are running:
eClimate Notebook from IPI is such a great tool. Proud to plug it!
Winterthur reports a decrease in its energy costs, which include the reduction in the use of fresh water, and intends to repurpose energy costs into programming.  Now that’s sustainable!

42nd Annual Meeting – Paintings Specialty Group Tips Session, May 29

The PSG tips session at the 42nd annual meeting took place prior to the afternoon session on Thursday, May 29th.  The following recaps the twelve tips that were presented.  I’ve done my best to give you the most complete information possible, but please feel free to contact each tipper for more information or for clarifications.  You can also always enter your questions into the comment section below!
 
Tip 1:  “Texas Strappo” varnish removal, presented by Helen Houp
Helen began with a case study of a damaged painting with a thick varnish that needed to be removed.  The thickness of the varnish combined with the severity of the damage to the painting precluded the use of traditional methods of varnish removal.  A search for treatment alternatives led to the use of pressure sensitive tape for varnish removal.  The tape was applied to the top layer of varnish and then pulled away gently to remove a thin layer of material without risking the paint underneath.  It was also possible to use the tape to remove overpaint.  The method allowed for a controlled removal of the varnish and overpaint in layers without leaving behind significant residues.  I was unable to determine the type of tape that was used, but I’m sure Helen would be willing to provide details to those who may be interested.
Tip 2:  Reverse of Paintings Database, presented by Elise Effmann Clifford
Elise previewed a database for “Information on the Reverse of Paintings” that she has been developing in cooperation with the Fine Arts Museums of San Francisco, which will host the final site.  The goal for the completed database is to provide a searchable and expandable archive of shared information specific to the reverse of paintings with international access and contributions.  In the interest of security and permissions, a login will be required and it will be possible to make entries available to the general public or adjust privacy settings to limit viewing.  Members will be able to upload images with file size allowances up to 30MB.  Transcriptions and key terms will allow searches for details like canvas stamps, stencils, labels, and seals.  The project is destined for beta testing beginning some time in July 0f 2014.  People interested in taking part in the testing or submitting future contributions should email Elise.
The presentation of the database was followed by a brief question and answer period.
Q:  Will any of the information contained in the database be found through a general internet search?
A:  That will depend on the privacy settings.  There will also be terms and condition sections on the site as well.
Q:  Will uploaded images become property of the Fine Arts Museums of San Francisco once they are uploaded?
A:  No.
Q:  Will the database accept video?  What kind of images are accepted?
A:  It will not take video.  Right now it cannot take RAW images but will handle things like jpg, tif, etc.
Tip 3:  Filling cracks at the edges of canvas, presented by Kristin Robinson
Fine cracks along the turnover edges of a canvas can be very difficult and tedious to fill.  Kristen suggested using dried modostuc, which can be held in the fingers and gently rubbed over the cracks to fill them quickly and safely.  The dried material leaves very little residue and what remains can be gently wiped way.
Tip 4:  Edge lining iron support, presented by Kristin Robinson
Kristin followed her first tip with a suggestion for edge-lining.  A backing board or mat board can be folded into thirds to form a triangle, which can act as a rigid support for the iron to press against when applying an edge lining on folded margins.
Tip 5:  IMAT developments, presented by Nina Olsson
This tip focused on recent advancements of the IMAT project, which is the natural progression of an earlier project Nina introduced to the Paintings Specialty Group in a talk presented at AIC’s 38th annual meeting in Milwaukee.  IMAT refers to “Intelligent Mobile Accurate Thermoelectrical” mild heating devices.  The aim of the project is to provide conservators with a controlled and mobile tool for the structural treatment of materials.  It is worth noting that Nina is a paintings conservator but the IMAT was developed with a broad audience in mind, including but not limited to conservators of works on paper and textiles.  The details of the IMAT project are significant and advanced so this is merely a summary of what was presented at this tips session.  Links to more detailed information about the IMAT are included at the end of this summary.
The current IMAT team has developed working prototypes that should be ready for production within a few years.  The current focus is on low temperature applications that can be sustained for many hours at a time with a low voltage requirements (I wrote 70-150 degrees Fahrenheit and 36 volts, though these should be confirmed through additional resources).    The carbon nanotube heat source is galvanically insulated and has a thermosensor connected through bluetooth technology with a touch screen control for heating over time within a 0.5 degree Celcius fluctuation.  The mats will be flexible and come in various sizes, though any customizable size will be possible.
There are 3 IMAT forms at present.  The first is a standard mat that is opaque and does not offer any breathability.  The second is a black mesh mat with a gray polyurethane coating and thin silicone coating.  The third, which is still in development, is a transparent mat with silver nanotube technology.  A fourth incarnation–a textile-type mat of silk organza with silver nanowire–is next in line.
All questions regarding the history and current developments of the IMAT project can be directed to Nina Olsson.  Additional information can also be found via the following links:
PSG 2010 Postprints
imatproject.edu
H. Meyer, K. Saborowski, T. Markevicius, N. Olsson, R. Furferi, M. Carfagni. “Carbon Nanotubes in Art Conservation.” International Journal of Conservation Science. 4 (2013): 633-646.
Tip 6:  PSG Wiki, presented by Gabriel Dunn and Erin Stephenson

In May of 2013 a core team of paintings conservators formed the Paintings Specialty Group Wiki Committee under the guidance of Chief Wiki Editor Erica James.  The group worked to bring organization to the PSG wiki page.  Gabriel and Erin presented the improvements that were made to the page and announced that the group is seeking contributions.  They encouraged the PSG membership to visit the site and consider submitting material or reaching out to be paired with a liaison who can submit material on their behalf.  Any questions or concerns about the PSG wiki can be directed to Erica James or any member of the current Wiki Committee listed on the main PSG wiki page.
Tip 7:  Fume extraction, presented by Robert Proctor
Rob presented a design for a fome-cor “cabinet” that he built to enclose a painting during varnishing.  The structure can fit around a painting to contain fumes, and hoses attached to the structure will remove the fumes before they escape into the studio space.
Another fume extraction tip involved the wheels on portable fume extractors.  Rob mentioned that the ones sold with the portable extractors are expensive and mark floors.  He suggested making a mobile base using wheels purchased at a home improvement store that will not mark the floors.  As a side note, he added that it is not necessary to purchase the proprietary prefilters for the portable units because those used for home air conditioning units work just as well.
I’m certain Rob would be happy to provide details for anyone who wants more information on his designs!
Tip 8:  Building your own microscope, presented by Ria German-Carter
Microscopes are expensive and can be an especially significant cost for conservators in private practice.  When faced with the task of acquiring a new microscope, Ria decided to put together her own.  She was able to find some good quality used components on eBay and save on additional parts by purchasing through amscope.com.  She built an inspection microscope with the following specifications for under $1000:

  • 8 inch working distance
  • articulated arm
  • different camera mounting tubes
  • LED lighting
  • fiberoptics

Unfortunately, I missed the specification regarding the microscope’s magnification.  Please contact Ria if you would like more details!
Tip 9:  Laser line for cutting batting and what to do with the scraps, presented by Chris Stavroudis
Chris gave a simple but effective tip to assist in cutting a straight line in batting material.  He placed the line across the batting and was able to cut a smooth line without needing the assitance of a physical straight edge.  He suggested using scraps of batting for cleaning dishes, lab tools, or as a less abrasive material for surface cleaning.
Tip 10:  More fume extraction, presented by….
I apologize to this tipster for missing their identity!  Please comment below if this is your tip.  It described the use of a dryer tube/trunk for fume extraction rather than buying a specialized trunk.  White mesh can be put ver the tube to make it less like a dryer tube and a PVC cap can be added to the end for finish and for weight.  An angled piece, such as those used for water heater tubes, can be used to create a swivel at the end of the tube.
Tip 11:  Proper ventilation, presented by Daisy Craddock
This wasn’t a traditional tip, but is still important information.  Daisy pointed out that exhaust systems, such as elephant trunks, need to exhaust to the outside of a studio because they don’t remove all vapors and may produce precipitants.  She also reminded us that microemulsions do not get extracted at all.
Tip 12:  Storage rack solutions, presented by Kate Smith for Gordon Lewis
Gordon was not in attendance at the tips session so Kate presented his images of a storage system that involved the use of foam board.  It appeared that the foam was used as an inexpensive alternative material to create slots in his storage racks.  Gordon may be able to provide more details about his tip if interested people wish to contact him.
 
Thanks for the tips, everyone!

42nd Annual Meeting, Collection Care Session, May 29, 2014, “The Future of Risk Assessment: Developing Tools for Collections Care Professionals” by Beth Nunan

Beth Nunan of the American Museum of Natural History described an almost 10-year approach to gather data across the many departments of the museum, using the cultural property risk assessment model (modified for AMNH). No one wants their risk assessment survey to sit on a shelf, and one thing is for certain: if the data cannot be compared across collections, the data will stay unused and uninterpreted. Even if the data is used, it can be called into question if the tools that captured and analyzed the information are perceived as biased.
Here are some of the takeaways from the AMNH approach:
1) The more complex the collection program at a museum, the more difficult it is to comprehensively apply and manage a risk assessment project. At the American Museum of Natural History there are millions of specimens ranging from vertebrates to botanical specimens and including libraries and archives.
2) There is a trend that AMNH is following about being able to compare risk assessment data with other like museums. Sharing risk assessment data and finding benchmarks across the museum field is becoming important; so risk assessment surveys should consider what will be the common data points shared with other museums, and what the definitions of those data points are.
3) Once tools are developed they should be shared with other professionals to amplify the use of the tools at other institutions. Groups like Collection Care Network and others are seeking to standardize templates and tools in order to facilitate comparison.
4) Partners are crucial to the success of risk assessments. Partners are frequently allied professionals, such as curators, librarians and archivists.
It’s clear that AMNH has many challenges in developing the tools it has used for risk assessment, but I expect we will hear much more from the conservators there as they promote their tools and lead other natural history museums towards this smart way of evaluating risks.

42 Annual Meeting-Joint Session: Paintings and Wooden Artifacts, May 31st, "Modern Materials and Practice in Gilding Conservation", Hubert Baija

Hubert Baija, Senior Conservator of Frames and Gilding, has been responsible for overseeing the conservation of the frame collection at the Rijksmuseum Amsterdam since 1990. Numbering over 7000 frames that are now accessioned and inventoried as works of art in their own right, Baija has had the opportunity to treat frames of different styles and condition issues. During his presentation, he discussed three treatments. He emphasized the need for close study and observation of the original materials, understanding the appearance and intended effect created by the frames in their original lighting situations, and choosing reversible materials in a creative way. He noted that a treatment need not be overly involved to successfully reintegrate the gilding.
His first case study was the treatment of a Louis XVI oval frame (1777-89) that was original to the portrait it framed. The discussion addressed the past practice of covering worn gilding with bronze paint, that later had been retoned with a dark glue/pigment layer to match the discolored bronze. These layers significantly altered the intended appearance of the frame, by negating the play of dark, light, and reflectance across the complex surface. Baija demonstrated that by removing the glue and bronze paint layers (using simple solvent mixtures), only a minimal amount of inpainting was necessary to reintegrate the gilded surface. While the improvement to the frame was impressive, the appearance of the painting when displayed in the frame was also significantly improved by the intervention.
Baija’s second example demonstrated his skill as an artisan, his keen observation, and his determined investigation of a little know technique that had previously been overlooked. He stylistically identified a pair of auricular frames carved from lindenwood to c.1660-1665. Both frames had significant worm damage, had lost smaller portions of carved decoration, and were overpainted and overgilded. Only small areas of the original gilding remained intact–between 5 and 30%.
The original gilding was done using a type of mordant gilding that is not known from historical texts and has not been identified before. Using SEM-EDX imaging of cross sections, the technique was characterized: the bare wood was prepared for gilding using a thick glue layer (1 mm Th), followed by a pigmented emulsion layer, to which the gilding was applied.
Noting that the tradition of gilding in the Netherlands had been lost since the 1580s, and that more traditional (and stable) gilding techniques would not be reintroduced to the Netherlands until later in the 17th century by French Huguenots, Baija surmised that this unusual technique was in use—only in the Netherlands–for a relatively short period of time. After his initial characterization of the technique on these frames, he has since identified other examples on Dutch frames and furniture that are stylistically dated to 1650-1680. Because the technique was inherently unstable given the response of the thick glue layer to changes in humidity, many pieces gilded using this technique have subsequently been overgilded.
After cleaning the frames of non-original layers, the carved losses to the wood were reconstructed using paper mâché /methyl cellulose mixture, mixed with water. The material can be handled like clay to buildup the appropriate forms. The paper mâché shrinks slightly, allowing for application of Modostuc finishing layer. Because an isolating layer of Paraloid B-72 had been applied to the original wood surface, the paper mâché fill remains easily reversible. Shallower losses were also filled with Modostuc.
Most creative was Baija’s approach to inpainting to create the illusion of distressed gilding. Noting that the original thick glue layer would only be very slowly soluble in water, gouache was chosen to provide a brown base tone over areas of lost gilding and structural reconstruction. Islands of worn gilding were recreated using mica pigments mixed with Schminke watercolors, masterfully creating the illusion of a worn gilded surface. Final toning was done using ethanol soluble dyes in Mowilith 20. Toning could also be done using Gamblin Conservation Colors, PVA, etc. Coincidently, the dating of the frames was confirmed and the paintings and frames temporarily reunited, when an early 20thC. photograph of the frames paired with their original paintings was identified. The paintings are signed and dated 1661.
In his final example, Baija described an approach to reintegrating an area of loss in the gilding on a panel painting by Lorenzo Monaco, Stigmata of St Francis, c.1420. The area of damage was on a stepped join that was filled using Modostuc and prepared for gilding with acrylic bole from the Kolner system. Baija emphasized the importance of selecting a gold that was the correct color, but lighter in tone than the final appearance needed. He noted that any toning layers/coatings would take away from the intended appearance of the gilding—imitation of solid gold. By simply inscribing the cracks in the newly gilded loss, using horizontal lines to disrupt the vertical disruption of the loss, the gilding was effectively knocked back to the correct tone. Minor glazes to create the effect of dirt in the cracks were then applied.
Each of these treatments demonstrated issues that are common to conservation of gilded objects. Gilded surfaces are often overgilded or painted with bronze paint to recreate the impression of gold. Alternatively, gilded surfaces tend to be toned dark, either to reintegrate corroded bronze paint or to tone back gold that may seem too garish or is disrupted in other ways.
Baija’s approach is one that brings back the appreciation of frames as works of art, rather than as just accessories to paintings. It emphasizes the need to understand the original and aged appearance of the gilding, and to recover what is left of the original. His approach is one that acknowledges the frames—like objects and paintings–should be treated in reversible ways, using conservation materials distinguishable from the original materials. It thereby breaks from the traditional approach of regilding frames using traditional materials and techniques. He encourages the exploration of new materials, the use of reversible layering systems, and acknowledging the patina of time and use. An overall theme of the talk was one of reintegrating the gilding only to the level of the best-preserved area of original gilding.
For those interested in furthering their understanding of gilding and approaches to gilding restoration, Baija teaches two workshops at the Campbell Center in Mt Carroll, Illinois. “Traditional Gilding” and “Gilding Restoration” combine lecture and practical work in the studio. I attended both workshops over the last two summers, and as a result have improved my treatment approach for gilded frames. I highly recommend them.

42nd Annual Meeting – Paintings Session, May 29 “Illumination For Inpainting: Selecting an Appropriate Color Temperature” by Steven Weintraub

So why do conservators prefer northern daylight for inpainting? In Steven Weintraub’s talk titled “Illumination For Inpainting: Selecting an Appropriate Color Temperature” which he presented in the Paintings Session at the 42nd Annual Meeting in San Francisco, he answered this question, as well as a few others about light sources and selecting an appropriate color temperature.
Steven explained how, in his opinion, it is the distribution pattern of skylight that helps make it so ideal. When diffuse skylight from a north-facing window enters a room, there is a “soft” directionality. This type of light distribution avoids the problem of harsh shadows typically associated with point sources of light. It also avoids the opposite problem of flatness due to the absence of shadows, a condition associated with diffuse sources such as over-head fluorescent lamps.
Using only skylight or daylight for inpainting, however, sets the conservator up for two problems: The first, as Steven mentioned in his abstract, is that the availability and control of northern daylight limits the amount of time, and the location in which it can be used. This becomes a real problem if you happen to be facing a tight deadline during the short winter days in the northeast, or like myself, have constantly changing lighting conditions, such as those during the bout of thunderstorms that we often have here during Houston summers. The second problem, which Steven explained in more detail during his talk, is that the spectral power distribution of typical sources of gallery lighting is pretty much the opposite to that of daylight. The result is that if inpainting is done only with daylight, it increases the risk of metamerism when exhibiting the artwork in an electric lighting situation utilizing a warm color temperature source.
It is for both these reasons that many conservators opt for a mix of electric light and daylight for inpainting, and when possible, test the matching of inpainting in the lighting conditions for which it will be displayed.
But, how does one choose an appropriate electric light source? Steven explained his research and suggested that selecting an appropriate color temperature with adequate color rendering properties was a key.
Apparently, color temperature in the range of 3800° Kelvin is the magic number. From Steven’s talk, I learned that color temperature within the 3800°K range is the transition point between warm to cool on the color temperature scale. Within this color temperature range, Steven theorizes that one gets the best balance of saturation with warm and cool colors.
Steven concluded his talk by illuminating a pair of reproductions of a very well known painting by René Magritte, demonstrating the difference in appearance of the image in various color temperature lighting conditions. This showed how the moderate (3800°K) range really did look the best.

42nd Annual Meeting – Research and Technical Studies, May 29, "An Examination of Light-Induced Color Change in Anoxia and Hypoxia using the Microfading Tester " by Vincent Beltran, Jim Druzik, Andrew Lerwill, and Christel Pesme

Vincent Beltran from the Getty Conservation Institute presented this talk in the Research and Technical Studies session. The study presented examined the effects of anoxia and hypoxia on light-induced color change in a sample set containing a variety of materials. The goal was to examine the use of these environments in storage and exhibits as part of an effort to improve the experience for visitors viewing light-sensitive items.
The talk was organized into four parts: “Introduction,” “Experimental Method,” “Microfader Results,” and “Comparison to Lightbox Study.”
In the introduction, Beltran reviewed traditional practices to mitigate the damaging qualities of light. For example: reduce light levels, limit exposure time, rotate exhibit items, and store items in the dark. He then provided an overview of the photo-oxidation process, and the theories behind the use of anoxic and hypoxic environments for storage.
A 2012 study of 125 colorants exposed in a halogen lightbox for 17.5 MLux hours at 22° C, 40% RH with oxygen levels at <10 ppm indicated that 90% of these items studied showed reduced color change as compared to the same items stored in air. To the authors, the logical extension of this study was to transfer the test to the microfading tester and compare the results.
The design of the lightbox for the microfading tester study involved a xenon light projecting through ¼” starfire glass to items on a sample stand. Light was reflected to a spectrometer located above the glass. A ½ cm gap existed between the samples and the glass. The microfader was located above the case while the colorants were inside the case. The colorants consisted of 3 blue wool, 4 organic dyes, 2 leaves, 1 grass, 5 gouaches, 1 watercolor with prussian blue, 1 Kremer Prussian Blue, and 1 Crystal Violet. The colorants were exposed for 5 MLux hours in air, anoxia (<200 ppm oxygen), and hypoxia (1% and 5% oxygen). Reflectance spectra were obtained and combined for a color change plot.
The results of the microfading tester study showed that for the most part color change in air is higher than that in anoxia. Anoxic environments seemed to be generally equivalent to the 1% oxygen environments. A few colorants exhibited a slightly decreased change in the 1% environment but Beltran indicated that these results were inconclusive. A few exhibited increased change in the 1%. Environments with 5% oxygen tended to exhibit more change than anoxic or 1% but generally not as much change as found in air. The exception to this is Prussian blue, which shows the opposite behavior – an air environment showed the least change, 5% followed, and 1% and anoxic showed the most change. Overall, the results showed that 12 of the 18 colorants exhibited greater change in air while only one (Prussian blue) exhibited the greatest change in anoxia. Generally, hypoxic environments exhibited less change than air.
Beltran then presented a comparison between the 2012 study and the more recent microfader study. The main differences in the studies were as follows:
 
Study Component:         Microfader                                           Lightbox

Light Source:                    Xenon                                                     Halogen
Exposure level:               5 MLux                                                   0.01 MLux
Exposure time:                3.5 hours                                               1750 hours
Exposure type:                Continuous                                           Start/End
Area exposed:                  4 mm spot                                             Broad exposure

In general, the color change with the lightbox test was higher than that seen with the microfader, though some samples showed changes which were roughly equivalent. Most items showed similar behavior between the two techniques but the lightbox displayed increased change. The differences in the studies were typically within one blue wool step, and the study was able to consistently classify relative color change between the two techniques. However, Beltran stated that there is reciprocity failure between the two studies.
Future goals of this project are to repeat the analysis with more samples, examine the effect on reciprocity for the microfading tester at reduced light intensity, and study the color change in various RH and temperature levels.
Questions were as follows:
Q: In cases where the microfading tester and lightbox didn’t agree, is the lightbox the more reliable?
A: In general, lower light exposure tends to be closer to what you’d get with the microfading tester but that doesn’t mean reciprocity is holding.
Q: Has the microfading tester been tried with a halogen bulb?
A: No, they tried to modify a halogen source but it didn’t do much.
Q: Were control samples used?
A: No, they were not..

42nd Annual Meeting – Research & Technical Studies, May 31, “Development and Testing of a Reference Standard for Documenting Ultraviolet Induced Visible Fluorescence” by Jennifer McGlinchey Sexton, Jiuan Jiuan Chen, and Paul Messier

Jennifer McGlinchey Sexton, Conservator of Photographs at Paul Messier, LLC, presented on the testing of reference cards and the development of new imaging protocols that are so desperately needed in our field for increased standardization and comparability of photographs taken of UV-induced visible fluorescence phenomena. The project started by private photograph conservator Paul Messier in 2006, under the servicemark name UV Innovations (SM), was taken over by Jiuan-Jiuan Chen, Buffalo State’s Assistant Professor of Conservation Imaging, Technical Examination, and Documentation at Buffalo State College. Sexton has directed development of the  Target-UV™ and UV-Grey™ products since 2012.
Many a visual examination is followed by technical imaging, including both Ultraviolet Fluorescence (UV-FL) and Visible-Induced Luminescence (VIL), and Sexton’s talk first reiterated why observing cultural material by using carefully selected wavelengths of light is important:  It is non-invasive, relatively inexpensive, accessible, and (largely) commercially available. As a surface technique, UV-induced fluorescence probes outside layers, coatings, optical brighteners, mold, tidelines, and organic-glaze pigments above bulk pictorial films. Although it is a technique we rely on for the large majority of condition assessments and technical studies, our documentation remains unstandardized, and essentially, unscientific. With so much to gain by standardizing our capture and color-balancing process, as well as by taking careful notes on the equipment used, the prospect of the Target-UV™ and UV-Grey™ UV-Vis fluorescence standards is certainly an exciting one.
UV-FL images are unique in that they contain diagnostic color information, hence the need for standardization, which would enable cross-comparison between colleagues and between before- and after-treatment documentation. The beta testing of the UV target which was been carried out for 2 years has attempted to account for the most significant variables in the production of UV-FL images. The talk evidenced the enormous amount of collaboration and communication needed to streamline the significant aspects of equipment choice, the optimization of acquisition, and the documentation of post-processing methods. The goal was to increase reproducibility and comparability. Sexton’s presentation showed that the beta testing of the product achieved demonstrable results in terms of uniformity of output.
Development of the UV target was begun in collaboration with (Golden) to produce stable fluorogenic pigments of known color values and known neutral-gray values (which were evidently produced by mixing the red, green, and blue fluorogenic pigments). Neutral gray was defined as a gray which was interpreted as neutral by many viewers and which performed similarly under many different conditions. Including such color swatches within a photograph–for the purposes of color-balancing and correcting any variation in the Red-Green-Blue channels for each pixel–is a very familiar principle in visible photography.
A second consideration made for the round-robin testing was that of intensity, which is a variable somewhat unique to UV-FL photography. The nature of the emissive source must be noted for purposes of calibration and exposure, especially as all light sources currently used in fluorescent photography lack stability over long periods. The output of a lamp with fluctuate over time, and this makes relative intensities of materials illuminated with some lamp types very difficult to determine. Even when this particular factor is taken into account, other variables, such as the distance of the lamp to the subject and the wattage of the lamp will effect intensity. It is also possible that multiple emitting sources could be present. These factors should be included in the metadata for the exposure.
To control for this intensity factor, beta testers were to divide their sources, distance-to-subject, and wattage parameters into three different intensity levels which were best matched to certain analyses: “Ultra” was beta-tested for analysis of optical brighteners and other products produced specifically to fluoresce. “High” was best for the analysis of natural and thicker fluorescence, perhaps of a paint film such as zinc white, of some feathers (see Ellen Pearlstein’s talk from this year Ultraviolet Induced Visible Fluorescence and Chemical Analysis as Tools for Examining Featherwork”), and uranium glass colorants; and “Low” was used to image thin applications of resins, varnish, and sizing films.
A third variable was that of camera sensitivity, which varies with manufacturer (proprietary internal filtration and software), camera type (either DSLR or digital back cameras), as well as with sensor type (CCD or CMOS, modified or unmodified). Different filters were tested (Kodak Wratten 2e pale yellow filter, PECA 918, and an internal blue-green IR (BG-38) filter). These types of internal filtration are typical on digital cameras to block out IR and some red light to bring the camera output closer to the typical photopic curve of the eye and more closely mimic human vision. The 2e filters UV radiation and a small amount of the blue light commonly emitted by UV lamps, while the Peca 918 is used for IR blocking.
The fourth variable tested was the source type. Those tested included low-pressure mercury, high-pressure mercury, arc and metal halide arc lamps. Although LEDs were used at some institutions, many of these have a peak emission at 398 nm, which is barely in the ultraviolet range. Greg Smith at the IMA analyzed Inova X5 UV LED, and found that it does contain UV but is more expensive. Other products show a large difference in emission peaks which often cannot be accommodated by a simple white-balancing operation. Therefore, testing limited the peak emission to the most common types, emitting between 360 and 370 nm.
The last variables that were analyzed were those of post-processing procedures and software and of user perception and needs. An problematic paradigm identified over the testing period was that of the image being readable or resolvable vis-à-vis a particular argument versus the image being strictly accurate and well-calibrated. A photograph may accurately render the intensity of the fluorescence but it may be so completely underexposed so as to be unreadable.
Testing showed that, despite these difficulties of calibration and subjective experience, that the workflow incorporating the UV Innovations standard, showed a marked increase in standardization. Round-robin testing was completed by eight institutions in the US and Europe in May 2013. Fluorescent object sets were shipped along with the UV standard and filters. Each test site collected two image sets, one named “a,” using the lab’s current UV documentation protocol with color balance and exposure set “by eye,” and the other named “b” using the UV innovations protocol. The increased control provided by the use of the standard was evidenced by the average delta E of L*a*b* data points as well as the average standard deviation of RBG data points for both a and b sets as each institution. By way of example, the ‘Low—a” set showed an improvement from a delta E of 18.8 to the ‘Low—b” with a delta E of 4.9. The average standard deviation in-between these two sets showed an improvement from 32.8 to 6.2!
The presentation went into depth about how this data was collected, how variables were controlled for, and how the data was analyzed, and it showed convincingly that despite the high variability of current work flows,  the UV Innovations UV-Grey card and Target-UV standards in conjunction with standardization of UV source and filtration can markedly improve the image variability of UV-FL photography.
One variable in “extra-spectral” imaging that was not addressed in this talk were the spatial inhomogeneities of the light source, or the gradient that results from the use of an inconsistent light source. This could be especially problematic if using UV-FL photography for condition imaging, and “flat-fielding” should be considered as a possible augmentation to the ideal image-acquisition protocol.
There is still further research to be done before this product hits the market. A fourth intensity level will be added to increase the flexibility of the product. The current prototype features two intensity levels on the front and two on the back. Notably, artificial aging must be done to determine when the product should be replaced. As this current standard only operates over UV-A and UV-B, UV Innovations looks forward to developing a UV-C standard, as well as a larger format target.
The prototype of the Target-UV and UV-Grey cards were handmade, but the company hopes to overcome the challenges of large-scale production and distribution by Fall 2014.

42nd Annual Meeting – Paintings (Joint with Wooden Artifacts), May 31, “Painted Totem Poles at the American Museum of Natural History: Treatment Challenges and Solutions” by Samantha Alderson, Judith Levinson, Gabrielle Tieu, and Karl Knauer

Those who have beheld the Hall of Northwest Coast Indians at the American Museum of Natural History and its extraordinary “totem poles” will instantly recognize the potential scope of any study or treatment of such massive artifacts.

The Hall of Northwest Coast Indians, which opened in 1900, highlights the traditional cultures of the native peoples of North America’s northwest shores from Washington State to southern Alaska, including the  Kwakwaka’wakw, Haida, Tlingit, and others. (Source: AMNH.org)
The Hall of Northwest Coast Indians, which opened in 1900, highlights the traditional cultures of the native peoples of North America’s northwest shores from Washington State to southern Alaska, including the Kwakwaka’wakw, Haida, Tlingit, and others. (Source: AMNH.org)

 
These objects are housed in the earliest wing of the museum, curated at its inception by Franz Boas, “the father of American Anthropology”, who organized the early acquisitions of the museum according to a revolutionary argument: that of “cultural relativism” in opposition to a chauvinistic, social-Darwinist organization that put “primitive” peoples at the bottom of an evolutionary tree, the pinnacle of which was white America. Today, this hall holds a landmarked status and remains relatively unchanged, as the poles are very hard to move.

Ten years ago, a renovation of the hall was proposed. Although the recession thwarted plans, the objects were still in need of stabilization and aesthetic improvements. Because this project—from its inception, through the research, testing, and execution stage, was so expansive—Samantha Alderson reminded her audience that her talk could only represent an overview of a four-year process. Those interested in a specific aspect of the project can look forward to in-depth, forthcoming publications.
One of the more important aspects of the research phase, and a professional obligation that is indispensable to the curation and conservation of native materials, was the consideration of ethical issues and provenance information. Most of these pieces entered the collection between the 1880s and the 1920s, and the majority has been on continual, open display since their arrival. Their presence in AMNH’s collection is widely acknowledged to be ethically complicated in itself, representing an era of unscrupulous dealing in Northwest Coast artifacts. (To read more about “Indians and about their procurable culture,” consult Douglas Cole’s, “Captured Heritage: The Scramble for Northwest Coast Artifacts,” about the coincidence of a taste for these native artifacts and the establishment of many of the country’s foremost natural history collections. (p.xi)]
The carvings, including the carved columns most commonly described as ”totem poles,” would have had numerous functions within their originating cultures: house frontal poles holding entry portals to buildings, interior house posts, welcome figures, memorial poles, and mortuary posts [For a technical study on these types of carvings, please consult “Melissa H. Carr. “A Conservation Perspective on Wooden Carvings of the Pacific Northwest Coast.” Wooden Artifacts Group Postprints. 1993.].
To further hone their understanding of provenance, the 2009 CCI “Caring for Totem Poles” workshop in Alert, Canada, allowed the authors to travel through British Columbia with curatorial consultants, native carvers, and native caretakers, in order to study the techniques of manufacture. It was also important to keep abreast of the expectations of the native communities that might be borne out over the course of any treatment intervention or re-installation campaign.
The original aim of this project was to provide structural stability to those carvings which exhibited highly deteriorated surfaces caused by the weathering and biodeterioration in their original environment. These instabilities were often exacerbated by inappropriate environmental conditions and restoration interventions in the museum. The most significant issue requiring treatment was the presence of wood rot, insects, and biological growth, present in the original environment and continuing to run their course.
Although climate control was installed in 1995, soot from the age of coal heaters and lamps still blanketed the inaccessible areas of the objects. Dust from visitor traffic also dulled them, as the hall is adjacent to the entrance to the IMAX theatre. Routine and well-intentioned cleaning was ineffective against a century of accumulated grime and dust and was causing surface loss.
The location of the Hall of Northwest Coast Indians in relation to the IMAX theatre
The location of the Hall of Northwest Coast Indians in relation to the IMAX theatre

 
As there is no barrier between the objects and the visitor, touching has caused burnishing and scratching. The unfinished wood readily absorbs skin oils; and graffiti and adhered chewing gum had also become a most-unfortunate problem.
Early interventions after acquisition had caused condition problems of their own, as old fills had a hardness or density that is inappropriate for soft, weathered wood. These fill materials were only becoming more ugly, unstable, crumbly, and cracked with age.
All of these factors, taken together, provided a huge impetus for treatment.
To begin the treatment-planning stage, the conservators at AMNH performed examinations under visible and UV radiation and mapped the observed conditions and materials using a streamlined iPad-based documentation protocol. In some cases the restoration materials observed provided evidence of institutional and condition history. Although there were almost no previous treatment records of these objects, comparison with archival photographs of many of the objects showed the rate of deterioration since acquisition and provided clues as to dates of interventions and installation history.
In summary of the object-treatment stage, vacuums and sponges were first used in an attempt to reduce some of the dinginess of the surface and to increase the legibility of the painted designs. The many resinous and waxy coatings had trapped so much dust, however, that this treatment did not always have a satisfactory result.
The question of solvent toxicity held sway in all aspects of treatment, as operations were completed in makeshift spaces outside of the lab, due to the size of the objects; these areas had no fume-extraction infrastructure. Luckily, plaster fills could be softened with a warm-water-and-ethanol mixture and carved out.
Temporary conservation lab set-up in the gallery.
Temporary conservation lab set-up in the gallery (See treatment photo gallery here).

 
Butvar B-98 and Paraloid B-72 were selected as potential consolidants and adhesives. A 5-10% Butvar B-98 solution in ethanol (i.e. without the toluene component for safety concerns) was used for surface stabilization, and Paraloid B-72 in acetone was used for adhesion of splinters and detached fragments.
Karl Knauer filling splinter edges.
Karl Knauer filling splinter edges.

 
Fills were designed using different materials depending on the location on the object. These were intended to reduce damage during installation, display, and regular maintenance. If the fill was not visible, shapes were cut from Volara, beveled, and adhered in place with Paraloid B-72 along the edges. These were often necessary on the tops of the poles to cover the deep voids of deteriorated wood. Some losses were back-filled with tinted glass micro-balloon mixtures of different grades and different resin-to-balloon ratios where appropriate. As some paints were solvent-sensitive, certain fills required the use of Paraloid B-67. The final fill type was a removable epoxy-bulked fill to compensate for deep losses in visible areas. These areas were first filled with polyethylene foam to prevent the fill from locking in. The edges of the fill area to be cast were protected by tamping down teflon (plumber’s) tape which conforms nicely to the wooden surface. West System 105 Epoxy Resin—with “fast” 205, “slow” 206, or “extra-slow” 209 hardeners—was used in different proportions to 3M glass microspheres and pigments to give fill material with various hardness, curing-times, textures, and colors (See Knauer’s upcoming publication in ICOM-CC Warsaw 2013 for more details). This method is notable for its invisibility, its reversibility, and its rejection of phenolic micro-balloons, which are an unstable and unsuitable and were historically used for such a wood fill merely for their brown color. Once cured, the bulked-epoxy (and the plumber’s tape) were removed and the fills were then tacked into place with B-72 to produce an aesthetically pleasing and protective cap.
Many losses which were previously filled were left unfilled, as would have been the case it they had been collected and treated today. Crack fills were incised so as to retain the appearance of a (smaller) crack.
Once the surface and structure was stabilized with the consolidation and filling operations, the team turned their attention to the various paint films to be cleaned. Many of these were proteinaceous but some were more similar to house paints. This data was consistent with the ethnographic findings and with current native practice. No preparatory layers were used, and the pigment layers were often very lean.
PLM, XRF, and SEM-EDS, as well as UV-FL imaging, thin sections, and analysis with FTIR was undertaken. Some binder analysis was also possible, but this was complicated by historical treatments. Interpretation of epi-fluorescence microscopy results was also thwarted by the presence of multiple coatings, the inter-penetration, -dissolution, and bleed-through of layers. As many as four different types of coatings were identified, and understanding and addressing the condition issues caused by these coatings became a primary concern. Cellulose Nitrate was often applied to carvings in the early 20th century. Whether this was to refurbish or protect, it has developed into a dark-brown layer which is alternately hazy and glossy and which obscured the original surface appearance. Lower regions evidenced PVA or PVAc on top of the Cellulose Nitrate. Shellac and dammar are present in isolated locations, as is an orange resin which eluded identification (even when analyzed with GCMS).
Although identification of these coatings was attempted, removal was not originally planned due to the difficulties designing a solvent system for its reduction, considering the variation in sensitivities, the interpenetration of the layers, and the unknown condition of the original paint films beneath. This plan changed when the poles were deinstalled for construction.
The treatment design was largely aided by the isolation of four house posts in the collection made by Kwakwaka’wakw artist Arthur Shaughnessy.
Arthur Shaughnessy carving one of these poles (Photograph by George Hunt, copyright AMNH).
Arthur Shaughnessy carving one of these poles (Photograph by George Hunt, copyright AMNH).

 
Commissioned by AMNH in 1923, these had never been installed outdoors but which had been coated in the same manner and exhibited in the same space. This allowed for the development of controlled methods for coating reduction.
A Teas table (or Teas chart) was used to identify potential solvents or solvent mixtures, which were tested over every color and monitored for any leaching or swelling. These initial tests were deemed unsuccessful.
In areas without paint, film reformation with acetone reduced haziness or glossiness. Where the coating was completely removed, the wood was often left with an over-cleaned appearance which necessitated some coating redistribution with MBK, MEK, and propylene glycol. Wherever possible, gels were used to reduce the exposure to toxic solvents. In painted areas, the large variation in solvent sensitivity, the inconsistency of media binders, the varying porosity of the wood, and the changing direction of the wood grain required that the conservators work inch-by-inch. DMSO, a component of “safe” stripper, and NMP were controllable over certain colors but caused considerable swelling.
February 2012, the museum saw the reinstallation of the Shaughnessy poles, marking the effective conclusion of the testing period and the successful management of a challenging triage situation by conservation staff.

It was Kwakwaka‘wakw artists like Arthur Shaughnessy who kept carving traditions active when the Canadian government prohibited the potlatch ceremony in 1885. The ban was lifted in 1951, after AMNH’s acquisition of the house posts.
The completion of treatment represents an important opportunity to educate the public: Although these monumental carvings are exhibited in a historic wing of the museum, we need to dust them off and remember that these carvings represent very, active traditional practices and communities.
There is still the need to develop more systematic solvent strategies, as well as to consult with a paintings conservator. But it is clear that these objects stand to look much improved after the grime and coatings are removed or reduced and the objects are thoughtfully reintegrated with a well-designed fill system. Thanks to the remarkable talents of the AMNH team, these stately creations are finally commanding the respect they deserve.
 
___
Resources:
Hall of Northwest Coast Indians :: AMNH
From the Bench: These Face Lifts Require Heavy Lifting :: IMLS
Arthur Shaughnessy house post carvings reinstalled following conservation treatment (February 2012) :: AMNH
Changing Approaches to the Conservation of Northwest Coast Totem Poles :: Reed College
Andrew Todd (1998). “Painted Memory, Painted Totems,” In Dorge, Valerie and F. Carey Howlett (eds.), Painted Wood: History and Conservation (pp. 400-411). Proceedings of a symposium organized by the Wooden Artifacts Group of the American Institute for Conservation of Historic and Artistic Works and the Foundation of the AIC, Colonial Williamsburg Foundation, 1994. Los Angeles: J. Paul Getty Trust.
A Brief History of the Jesup North Pacific Expedition :: AMNH

 

42nd Annual Meeting –Paintings Session, May 29, 2014, “Conserving Spanish Colonial Paintings – Finding the Divine in Conservation," by Cynthia Lawrence

In this Thursday afternoon talk, Cynthia Lawrence presented an in-depth look into the materials and condition problems frequently present in Spanish colonial paintings.
Dating from Columbus through the nineteenth century, Spanish colonial paintings have generally entered collections in remarkably poor condition. Because these paintings have not been widely studied or exhibited, conservators have infrequently encountered them for treatment.
Paintings from this period often did not receive an original application of varnish, and as a result, dirt and debris are found directly in contact with the paint layer.  Interventions by early restorers included varnishing and consolidating with wax, resins, and synthetic materials overtop of dirt, resulting in painted surfaces with an obscured, uneven appearance.
The structures of the paintings were often complex. Wood, fabric, paper, and metal served as supports for the paintings. Compositions sometimes included shell inlays and fugitive cochineal reds painted over thin grounds. Some paintings were executed directly on a substrate without the use of a ground at all, and canvases were often affixed directly to the stretcher.
Cynthia showed slides and presented summaries for the treatment of several Spanish colonial paintings featuring divine narratives. She began by illustrating a treatment of a painting of St. Thomas on laid paper over wood that exhibited convex warping, vertical wood movement, planar deformations, paint loss, heavy grime, and a dark varnish. Cynthia’s treatment included consolidating with isinglass and attaching the paper to the panel with BEVA. She cleaned the surface with aqueous solutions and used a xylene mixture to remove the varnish. B-72 was applied to the break edges, which were clamped and weighted. The painting was varnished with MS2A prior to fills and inpainting, and Regalrez 1094 with a bit of wax was applied as a final varnish. After conservation, curators were able to positively attribute the painting to Gregorio Vásquez, a well-known Colombian painter of the Latin American Baroque period.
Cynthia also discussed several treatments in which she found a variety of materials layered over the divine subjects.
A collagen-based glue was found on the surface of one painting, while synthetic varnish, acrylic, PVA, wax, and natural resin varnishes were found overtop centuries of accumulated soot and grime on others. Due to the varied solubilities of these materials, Cynthia employed mechanical action, aqueous solutions, and solvent-based mixtures to remove dirt and incongruous materials.
For all of the paintings she treated, Cynthia discussed the importance of judicious inpainting. She inpainted the most noticeable areas of damage in order to maintain unity in the composition, but the paintings were not aesthetically compensated to appear new. Since many were used for devotional purposes, Cynthia stressed the appropriateness of preserving them in a way that was sympathetic to their original display.
Cynthia’s talk brings attention to the need for continued innovation in conservation treatment, and more research and scholarship on Spanish colonial paintings.  Spanish colonial paintings are often in such poor condition as to be deemed “lost causes” or “problem children” by conservators, but she cautions that conservators will likely begin to see paintings like these more, as museums and collectors seek out lesser known works.  As we work to understand these paintings better through treatment, analysis, and historical research, we will undoubtedly come to balance creative problem solving with the painting’s long life and history — it is here that we find the divine.
You can see pictures of some of the paintings Cynthia Lawrence treated in this article, and visit the New Mexico History Museum’s page  featuring an exhibition of these works, on view until March 2015.

42nd Annual Meeting – Book and Paper Session, May 29, 2014, "Digital Rubbings. Monitoring Bookbindings with the Portable Mini-Dome (RICH)” by Lieve Watteeuw

In this talk, Lieve Watteeuw showed images produced by the Reflectance Imaging for Cultural Heritage (RICH) project and demonstrated the functionality of the Mini-Dome module. I was excited to see this presentation after reading advertisements for the “New Bownde” Conference at the Folger Shakespeare Library last year, in which the RICH project and Mini-Dome were featured. Fortunately, for those unable to attend the presentation, extensive documentation about the project is available online through the project’s webpage and blog.

Downloaded from: http://portablelightdome.files.wordpress.com/2013/11/foto-1.jpg
The Mini-Dome module

The Mini-Dome module is a small, hemispherical-shaped imaging device that is tethered to a laptop. The module creates dynamic digital images through polynomial texture mapping, a technique commonly referred to as Reflectance Transformation Imaging (RTI). This technique involves taking a series of images from a fixed camera position, while changing the angle of lighting, in order to reveal the surface of an object. The original dome was created in 2005 at Katholieke Universiteit Leuven for reading cuneiform tablets, but has since been used to image bindings, illumination, wax seals, cuir bouilli, and other cultural objects. The current module is equipped with a single 28 MP digital camera and 260 white LED lights to capture a total of 260 images in approximately four minutes. Watteeuw showed a video of the Mini-dome in action during her presentation, but readers can view a similar video here.
KU Leuven, Maurits Sabbe Library, second quarter 16th century, SPES Binding, panel stamp on brown calf leather.
Example of images and filters. KU Leuven, Maurits Sabbe Library, 16th century SPES Binding, panel stamp on brown calf leather.

After capture, Watteeuw described how the images are processed by software and interpreted by seven dynamic filters. She  demonstrated some of these filters, including sharpen, shading, generate models, line drawings, and sketch.  Using the mouse or interface buttons, the user can zoom in, drag the image, or change the direction of lighting in real-time. For those that would like to experience the software interface, a web viewer is available here. Watteeuw reports that the software suite can also export to 3D shaded or rendered modes.

Watteeuw’s presentation included a demonstration of a measurement tool built into the image processing software. The tool can be used to measure the distance between two points or generate a height map for a portion of the object. This blog post includes an image of a height map created on the blind-tooled surface of a leather binding. Watteeuw explained that by scaling the image, the measurements can be accurate to 10 microns.

Watteeuw’s presentation included several examples of how the Mini-Dome could be used to learn more about the production of a binding. Images of a late 15th century book of hours were manipulated with filters to show tool marks on the uncovered wooden boards, providing evidence of how the boards were shaped and the lacing of the sewing supports. A second example showed a 16th century book (pictured above and described here), in which the binder scored a vertical line in the leather to align a large, central impression. Watteeuw described instances in which previously unknown marks or designs were revealed by manipulating the filters or direction of the lighting, such as three leaves emerging from an emblem design, or shallow impressions from a decorative roll being more clearly defined. This tool could be quite useful for identifying individual finishing tools and documenting how they changed or became damaged over years of use.

In addition to leather bindings, Watteeuw shared images of Belgian damask silk, remains of a ribbon, and embroidered bindings from the Folger Shakespeare Library. Once again, the dynamic filters in the software suite were applied in order to enhance details of the objects. The “sketch” tool provides clear images of weaving and embroidery patterns and could be very useful to textile historians and conservators. The measurement tool could also be used to gather data on the thickness of threads or cord used to construct the object.

ccsmicrodome
The Micro-Dome module fitted to a copy stand.

The RICH project will continue until 2015 and additional investigations are already underway. Watteeuw reports that the topographic data from an object is exportable into spreadsheet form. Engineers on the team are currently exporting high points of objects scanned to create a large data set for further analysis. Additional projects include the development of optical character recognition (OCR) for specific tool shapes or patterns on bindings. Testing is proceeding on a smaller “micro-dome” (pictured above) that  is constructed in two pieces so that it can be placed inside the opening of a book to capture images of the gutter or surface of a page. Watteeuw described a student research project currently in progress to measure sewing in manuscript textblocks.

Two questions were asked by audience members following the presentation. The first individual asked if a database of the existing images is available. Watteeuw answered that an open access database of all images captured would be ideal; however, since this is a research project using prototypes, the team is collaborating with institutions to link with existing databases. A second audience member asked if any attempts had been made to identify tools of various workshops. Watteeuw replied that a corpus was needed before any comparisons could be made.

Advanced imaging technologies, such as RTI, offer tremendous opportunities for the study of cultural objects and for digital libraries in general. The RICH project has produced a suite of tools that could be used by scholars and practicing conservators to gain a better understanding of an object’s composition and production. Wider use of devices such as the Mini-Dome in imaging collections of note and greater access to the software suite is required in order to exploit the full potential of the technology.