AIC's 53rd Annual Meeting

Henry Wilhelm,
Founder and Director of Research and Publications
Wilhelm Imaging Research, Inc., Grinnell, Iowa, U.S.A.

Co-Authors:

Ken Boydston
Chief Engineer and Color Scientist
MegaVision, Inc., Ventura, California, U.S.A.

Joe Uziel
Curator and Head of Dead Sea Scrolls Unit
Israel Antiquities Authority, Jerusalem, Israel

Shai Halevei
Chief Photographer and Head of Multispectral Capture
Israel Antiquities Authority, Jerusalem, Israel

High-resolution multispectral imaging provides periodic full-image area, non-destructive and zero-contactmonitoring over both short and very long periods of time of cultural heritage materials, including photographs, paintings, fabrics, documents, books, tapestries, and other works of artistic and historicimportance with very large data sets consisting of up to ten thousand or more discrete colorimetric data pointsfor the short-term and long-term monitoring of full-tonal-scale – generally nonlinear – colorimetric changes (including in the UV and IR regions), in a fully time-integrated manner, that may take place over time in thefull image area and in the support material (front and back). Multispectral imaging can accurately monitor rates of degradation of optical brightening agents (OBAs) and can quantify gradual yellowish or other stain formation in photographs, including albumen prints, polyethylene coated (RC) papers, and other materials.

Multispectral imaging provides the ability to monitor glazed works periodically during exhibition without the necessity of removing glass or plastic sheets from their frames while the works remain on the wall. Likewise, works housed in anoxic frames may be monitored over the long term without opening the frames. Irregularities in image deterioration and/or staining brought about by localized variations with photographic materials and their chemical processing, washing, contamination during drying, or as a result of selenium, sepia, gold, or other chemical toning treatments, coating and varnish layers, laminates, and other steps employed in the creation and finishing of the work, integrated with the inevitably non-uniform contact with mounting, framing, and storage materials over time, and the effects of exposure to non-uniform lighting, environmental and “micro-climate” temperature and relative humidity conditions, can be assessed and compared over long periods of time in all areas of an image – including within very small image details.

Representative times currently required for a MegaVision camera-based high-resolution capture of an object are:
1 minute and 16 seconds for 16 sequential image captures with 16 different waveband illuminants (with no filter wheel captures), with an integrated lux exposure of 0.12 lux/hour (equivalent to <10 seconds of display at 50 lux), and 3 minutes and 15 seconds for 26 sequential image captures with 26 different waveband illuminants (capture time includes 10 filter wheel captures for a more comprehensive OBA degradation analysis), with an integrated lux exposure of 0.33 lux hour (equivalent to <1 minute of display at 50 lux). High-resolution multispectral camera captures provide extremely accurate color images that are superior to RGB captures. These images can be used to automatically generate lower-resolution RGB images for cataloging, websites, publications, posters, and other uses. These high-resolution images can also readily be used to make color-accurate facsimile prints for exhibitions and study. Multispectral imaging employed as a routine part of the acquisition and accessioning process provides a “time-zero” set of high-resolution spectral data for every object that can then be used for very-long-term monitoring.

This presentation will consider the formidable technical challenges of very-long-term monitoring in the context of the now more than 2,000-year-old Dead Sea Scrolls in Israel, and the ongoing programs to systematically multispectrally capture each scroll and scroll fragment, monitor, and preserve the delicateparchment scrolls and scroll fragments. During the coming hundreds or many thousands of years into the future, every single part of a multispectral imaging system and the associated computers, software and data storage systems, calibration targets – and our understanding of color science itself – will repeatedly become obsolete and must be replaced with new systems. Strategies thatwill ensure a continued high degree of accuracy relative to the original measurements are proposed.

Without a comprehensive multispectral monitoring program, conservators and other institutional caretakers will have little or no quantitative data concerning what has actually been happening to their collections as they age over time, and with the understanding that comes with that quantitative information, of how degradation may be slowed or halted by changes in display and loan policies, by the use of humidity-controlled refrigerated and sub-zero freezer preservation, and by other means, some of which are yet to be developed.

References:

1. Henry Wilhelm, “Monitoring the Fading and Staining of Color Photographic Prints,” Journal of the American Institute for Conservation, Vol. 21, No. 1, Fall 1981, American Institute for Conservation (AIC), Washington, District of Columbia, U.S.A., pp. 49-64.
2. JPL (Jet Propulsion Laboratory, Pasadena, California), “Conceptual Design of a Monitoring System for the Charters of Freedom,” Jet Propulsion Laboratory Publication 83-102, March 15, 1984. The Jet Propulsion Laboratory is under the jurisdiction of the California Institute of Technology, and is administered and funded by the National Aeronautics and Space Administration (NASA), a U.S. Government Agency that began operations in 1958.
3. Douglas G. Severson (The Art Institute of Chicago), “The Effect of Exhibition on Photographs,” Topics in Photographic Preservation – 1986 (compiled by Maria S. Holden), Vol. 1, pp. 38-42, 1986. American Institute for Conservation Photographic Materials Group, American Institute for Conservation (AIC), Washington, District of Columbia, U.S.A. Slightly revised, the article was reprinted in Picturescope, Vol. 32, No. 4, Winter 1967, pp. 133-135.
4. Alan R. Calmes, “Monitoring the U.S. Charters of Freedom by Electronic Imaging,” (U.S. National Archives and Records Administration, Washington, District of Columbia, U.S.A.), Proceedings of the International Symposium: Conservation in Archives, National Archives of Canada in conjunction with the International Council on Archives, Ottawa, Ontario, Canada, May 10-12, 1988, pp. 243-251.
5. John McElhone (National Gallery of Canada), “Determining Responsible Display Conditions for Photographs,” presentation at The Centre for Photographic Conservation Conference ’92: The Imperfect Image: Photographs, their Past, Present, and Future, Windermere, Cumbria, England, United Kingdom, April 6–10, 1992.
6. Henry Wilhelm, “Monitoring the Fading and Staining of Color Photographs in Museum and Archive Collections,”
   pages 239-266 in Chapter 7, “The Permanence and Care of Color Photographs: Traditional and Digital Color Prints, Color Negatives, Slides, and Motion Pictures,” by Henry Wilhelm withcontributing author Carol Brower, Preservation Publishing Company, Grinnell, Iowa, U.S.A., 1993.
7. W.A. Christens-Barry, K. Boydston, F.G. France, K.T. Knox, R.L. Easton, and M.B. Toth, “Proc. SPIE, San Jose, CA, 7249(8), 1-10 (2009).
8. Marc Kaufman, “Jefferson changed ‘subjects’ to ‘citizens’ in Declaration of Independence,” The Washington Post, July 3, 2010. “It took research scientist Fenella France [using a MegaVision Multispectral Imaging and Analysis System] weeks to pull out each letter until the full word became apparent.” “Finding Jefferson’s erased word is the library’s greatest accomplishment using

Vivex prints were initiated in 1928 by Color Photographs Limited (CPL, London) as a modified version of Carbro printing that was the dominant process in the 1930s for advertising and retail fashion. Vivex prints were produced in an industrial manner, using a standardized, mechanized protocol. It was the first laboratory to offer a color printing service to professional photographers. Fully operational in 1929, CPL produced several thousand prints in a ten years laps time, becoming the most widely used and reliable printing service in the UK. Despite being a cost-efficient company, CPL closed in 1939, with the beginning of World War II. 

The Vivex process uses three separation negatives created during shooting, using a one-shot camera or a Vivex repeating back. The process produces – in 80 steps – a pigmentary trichromatic print from the successive transfers of three primary images (yellow, magenta, cyan) inscribed in a pigmented gelatin relief. The colored carbon tissues used by CPL for printing were likely purchased from Autotype Company, based in London as well. 

Five Vivex color photographs by Egidio Scaioni, created between 1933 and 1939 and held at the Musée de la Mode de la Ville de Paris, Palais Galliera, were studied. The conservation state of these prints, and an advanced conservation project - as part of Loys Boivin's Master thesis at Institut National du Patrimoine - have triggered the need for analyses to better understand the materiality of these little-known objects.  

Fortunately, all five prints showed accessible margins for each colored layer. Thus, non-invasive XRF analyses were carried out in these areas to identify the pigments used. The cyan layer showed the presence of iron, evidence of the use of Prussian blue. Surprisingly, the yellow and magenta layers did not show any elements related to the presence of pigments. Samples were taken from lacunar areas in the margins of one print for additional investigations using Raman spectroscopy. The yellow sample showed a signal specific to Pigment Yellow 4 of the Color Index (C.I. 11665) or Hansa Yellow. The magenta sample showed an intense signal with multiple bands – likely an organic pigment – but has not yet been attributed due to the lack of published databases. 

The discovery of the synthetic organic nature of these pigments instead of the mineral pigments traditionally used for historical pigment prints raised doubts about the light-fastness of these objects. Microfading tests were performed on the colored margins of three prints: all layers are highly sensitive, despite a slightly more stable yellow layer. 

The industrial context of manufacturing might have guided the choice of new components, with the great color rendering required for the fleeting advertising and fashion fields, but less durable in time. These strategic choices are most likely part of a global context of industrial development, with massive production demand and high profitability. This study opens up new insights into the light sensitivity of pigment color prints, and the development of new approaches to exhibiting these rare historical prints.

The Wayside, a historic home in Concord, Massachusetts, is renowned for being the residence of several prominent 19th-century authors, including Louisa May Alcott, Nathaniel Hawthorne, and Margaret Sidney (Harriet Lothrop). In 1965, the house became part of Minute Man National Historical Park, marking the first literary site acquired by the National Park Service.

This presentation will focus on the ongoing efforts to preserve and conserve the collection of photographs permanently displayed in the house.

The walls of The Wayside are adorned with artwork, documents, and family photographs, many of which have been on display since their original placement by the owners. In 2023, a project was launched to address the conservation of framed paper artifacts on display. A team of paper and photograph conservator, along with object conservators, working through CCI Industrial Services, LLC, was contracted by the National Park Service for this task. The conservation work took place at the Historic Architecture, Conservation, and Engineering Center in Lowell, MA.
This presentation will delve into the decision-making processes behind the conservation efforts, considering the unique qualities of the artwork, its contextual significance, and the specific requirements of preserving it within a historic house setting. The collaborative efforts between conservators, curators, and National Park Service Project Inspectors will be a key focus.
The aim of the talk is to introduce the collection and highlight the factors specific to The Wayside that influenced the conservation approach. The presentation will be accompanied by images of the house and examples of the treatments undertaken.

This presentation will discuss the work conducted at the Archivo de la Memoria Trans Argentina (AMT) regarding the design and creation of custom storage systems for photographic materials.

A unique aspect of the AMT is its management and operation by the trans community. Individuals over 50 years old, trained from the ground up, work with their own materials, handling both the digitization and conservation of the archive’s photographs and documents. This approach ensures that the preservation process is deeply connected to and reflective of the community.

The AMT preserves a diverse range of photographic formats and materials, including silver gelatin prints (DOP), chromogenic prints, dye diffusion transfers, and negatives and slides on flexible plastic supports like triacetate and polyester.

Given the challenges of obtaining conservation supplies in Argentina, we have developed bespoke storage systems tailored to the specific needs of our collection. These systems are carefully designed to address the preservation requirements of our photographs and documents.

Before developing these storage systems, we ensured that the collection was properly organized, conservation conditions were assessed, photographic processes were identified, and an appropriate storage environment was established. The primary purpose of our storage design is to act as a physical barrier against environmental contaminants, fluctuations in relative humidity (RH) and temperature, particle deposition, abrasion, and improper handling.

Since our archive does not yet have permanent environmental controls, we decided to create multiple levels of storage and avoid using adhesives or plastics. Instead, all storage systems are crafted from cellulose-based materials that meet the following criteria: smooth and soft surface, dimensional stability, flexibility, white with no dyes or pigments that could migrate, long-term durability and performance, acid-free, free of peroxides and sulfur compounds, lignin-free, and devoid of plasticizers, resins, or waxes.

Locally available materials meeting archival permanence standards were selected for our storage systems. In Argentina, medical-grade paper is commonly used for photographic materials due to its technical specifications, which confirm its suitability for archival preservation.

The design of our storage systems was informed by the working methodology and the way materials are accessed and consulted. Consequently, we have developed paper envelope models, machine-sewn without adhesives, and designed folded models for folders and boxes to house individual items and photo albums. To standardize our processes and train new team members, we have created instructional documents and templates for the production of these storage systems.

Additionally, we have been monitoring internal and external environmental conditions using a data logger to assess how these multiple layers of storage serve as buffers against external environmental fluctuations. This presentation will include preliminary results from this ongoing monitoring, providing insights into the effectiveness of our storage solutions in mitigating environmental impacts.

The Biržiškos are meritorious Samogitian nobility family in Lithuania. Their history dates back to the 16th century in Karšuva patrimony. Mr. Leonardas  son  Mykolas (b. 1882) was one of the twenty of February 16th Act Signatories, a researcher of Lithuanian literature and folklore, the Rector, academic and professor of Vytautas Magnus University and Vilnius University. 

Vaclovas Biržiška (b. 1884) was a Lithuanian cultural scientist, the director of the libraries at Vytautas Magnus University and Vilnius University, the Dean of the Faculty of Law, academic and professor.

Viktoras Biržiška (b. 1886) was one of the creators of the Lithuanian Armed Forces, mathematician, the head and professor of the Department of Mathematical Analysis of Vytautas Magnus University and Vilnius University.

The reverse side of the Mr. Leonardas photograph is glued on thick cardboard. The surface side is framed with a hard greenish cardboard mat. The surfaces are very dirty, deformed, unevenly yellowing, spotted with insect excrement and spots of unclear origin, and dappled with spots that occurred from flowing fluid. Some parts at the corners and edges are missing, there are flaws and the paper is layered.

Silver gloss is visible on the surface of the photograph, and the features of the person in the photograph are highlighted with black lines. On the left of the upper part there is a slight flaw on the surface. 

The acidity of the paper was measured by a universal indicator. Acidity of the mat is pH ≈ 6. The acidity of the cardboard to which the photograph is glued is pH = 6-7.

After researching a paper fibre with a 2% aqueous sulfanilamide solution, it was found that the paper of the mat contains lignin, and there is no lignin in the cardboard on which the photograph is glued.

After visually evaluating the condition it was decided to restore the exhibit undismantled. In order to keep the restoration work safe, the order, techniques and materials to glue the flaws and restore the missing parts were considered with great responsibility. The surfaces of the exhibit were cleaned mechanically with wool, erasers of different hardness, and their shaves. The surface layer with insect excrement was removed with a scalpel.

The flaws and missing parts were restored in dry method by gluing the layers of restoration paper to achieve the thickness of the original cardboard. Cotton pulp paper and watercolour-toned Japanese Kizuki Kozo paper were used for restoration. It was glued with a mixture of corn starch plaster, Tylose MH300 and MH1000 aqueous solutions.

The restored parts of the surface of the mat have been retouched with watercolour and pastel, using the technique of dotting. Using a white watercolour pencil, the decorative strip of the mat and its inner edges were retouched as well as a sharp line of brown flowing fluid was split.

In the field of art conservation, understanding of an artist's chosen materials and their creative  application is fundamental. This holds true for photograph conservation, where a profound grasp of the historic evolution and chemistry of photographic processes is crucial for discerning and identifying each technique. However, deeper learning is achieved through hands-on engagement in the darkroom. Delving into the intricacies of photographic processes not only unveils the technology, tools, and chemistry underpinning their production  but also serves as an invaluable experiential learning tool. Darkroom practice enables observation and critical thinking  about a photograph’s evolution from its initial creation to potential display, and how these factors influence its long-term preservation. It also facilitates an understanding of the differences between genuine deterioration and intentional alterations made by a photographer. Creating photographs in the darkroom can combine research into the history and chemistry of photography with research into photographers, studios, and businesses utilizing these techniques today. The sensitivities of different emulsions can also be experimented with and observed. The addition of toners or other chemical baths in the darkroom can be understood by seeing the change in color of a print and its stability over time. This immersive exploration equips conservators with a dynamic perspective that informs their decision-making in the outreach, preservation, and treatment of photographic materials.  When creating albumen prints for example, the paper curls at all stages of production from the first application of the egg-salt mixture to the final wash bath. This demonstrates the inherent qualities of these prints and though we may consider curling damaging and work to keep the print flat, it is also an unavoidable part of the making process. While striving to maintain flatness, historically, albumen prints would be mounted to a paper board. This mounting process, though keeping the print from curling, could potentially introduce cracking in the emulsion over time. The tendency of the print to curl and potential cycles of curling and flattening demonstrate its sensitivity to moisture and the need for a stable environment and safe housing for long term preservation. Additionally, through making albumen prints, the similarities to the salted paper print process are clearly identifiable. The recipes for chemical baths and steps in the darkroom are nearly equivalent. It is understandable why their identification might be challenging. Finally, the darkroom also serves as a platform for outreach, where sharing the art and science of photography through workshops and social media can enhance public understanding and appreciation of art conservation. This is increasingly important in an era when images are so easily captured, duplicated, and distributed.

Images to be included on the poster:

• Creating albumen prints: fresh untoned print, fresh gold toned print, historic aged print
• Creating additive color screen plates: results from experiment, diagram of the layers
• Creating tintypes: the “negative” pre-fixer, final positive product
• Creating gelatin DOP: contaminated fixer resulting in pink print
• Outreach: social media- QR code to share, creating salted paper prints and leading workshops at SUNY Buffalo and WUDPAC photo block

For decades the Dahlia Sprayer has become one of the most used pieces of equipment in the paper conservation lab.  The Dahlia Sprayer is a trusted tool for treatment work, such as washing, humidifying, and other applications.  Being constructed from chrome plated brass, the sprayer is also known for its durability and reliability.  A conservator may run thousands of gallons of liquid through a heavily used Dahlia Sprayer over the course of the sprayer’s life.  But as ubiquitous as the Dahlia Sprayer is in our work, it also has drawbacks and problems.  After years of consistent use,  this expensive sprayer can stop working or fail to operate at optimal performance.  This can happen for many reasons, from hard water buildup to degraded O-rings, resulting in leaking, poor misting, or malfunctioning.  Fortunately, many of these issues can be addressed and aren’t difficult to fix.  Parts are easily available, and maintenance isn’t complicated.  This short tip talk will discuss the most common maintenance challenges with the Dahlia Sprayer, how to prevent these issues from happening and how to repair the Dahlia Sprayer when they do occur.