ART CONSERVATOR
DIGITAL
ALL IS NOT LOST: recovering and preserving art works from a fire
BROOK PRESTOWITZ | ASSOC. CONSERVATOR OF PAPER
MAGGIE BARKOVIC | ASSOC. CONSERVATOR OF PAINTINGS
A group of fire damaged paintings and works on paper were deposited by a private collector at the WACC lab for treatment in June of 2020. The collection came from an extensive house fire in Georgia in Fall of 2019. The toll of a fire in a house or institution can be devastating both physically and emotionally. Recovery and salvage efforts that follow are often overwhelming. This article will provide insight and guidance for dealing with fire damaged objects. The collection from this case study is shared to demonstrate a variety of condition issues that are presented after a fire and the risks and concerns with treating and preserving them. General recommendations regarding necessary actions to be taken after a fire are provided for private collectors at the end of this article.
INTRODUCTION
Damage to works of art caused by a fire result from high temperatures and combustion as well as from firefighting measures, such as damage from water or chemicals (i.e. fire retardant) used to stop the fire. Extreme temperatures and bright light during a fire will accelerate degradation processes [1] and alter works of art resulting in embrittlement, desiccation, scorching, faded pigments, fire blisters, charring, and loss due to burning. The smoke from a fire is a combination of fine soot particulates and toxic, volatile, organic compounds including carbon dioxide, water vapor, oxygen, and nitrogen. Many of the products contain free radicals that are highly reactive with either the materials composing an object or degradation products that were present prior to the fire.
Works of art are infused with these volatile organic compounds and soot, a combination of gritty and oily particulates, is deposited on the surface. The particulate component of smoke can contain heavy metals, such as iron, which cause catalytic degradation reactions in paper and media while the oily components are acidic and will cause acidic degradation. These particulates and free radicals present in the oxidation process of a fire may result in unwanted polymer reactions with the artistic materials: cross-linking with materials such as aged oil paint or varnishes becoming almost impossible to remove without doing more harm to the fragile object. These chemical reactions happen in a short period of time, so treating the object and removing these particulates needs to happen rapidly to prevent such degradation and avoid any further devastating changes to the object’s condition.
The soot from a fire forms a dark, distracting film over the artwork, making the composition illegible in most cases. The composition may be further obscured by fire retardant. There may also be issues caused by other objects falling or materials melting and depositing onto works of art. Additional physical damage may occur from displacement as the fragile and compromised items are removed from the house or from their cases and frames. Mold growth on damp objects and tidal stains from water used to extinguish the fire is another a major concern. Also, the volatile organic compounds and fire debris deposited on objects is toxic and requires appropriate health and safety measures, such as wearing a mask and gloves, while handling them. Once the collection arrived at the WACC, the conservators began working to mitigate the fire damage. The strong odor of smoke on these objects and the deposited debris required masks and gloves while handling them. Each work was examined and treatment proposals formulated. Fortunately, the collector was able to provide the WACC with photographs of the works from a 2006 appraisal. These photographs aided the conservators as they assessed the damage caused by the fire to the collection and determine treatment goals.
Condition Issues of the Fire Damaged Paper Works
Several watercolors and their frames were included in the group of fire damaged objects deposited at the WACC. Most of the frames for these works were severely damaged and not salvageable. However, the watercolors were in much better condition because the frame package, which includes glazing, window mat, and backing board, slowed the progress of damage caused by smoke, soot, and water damage. Even though the framing materials protected the watercolors, there were still many gaps that smoke and water was able to seep in and damage the works (fig.1).
FIGURE 1. Left/Top: The glazing of a framed artwork has protected the surface from soot, smoke, and moisture. Right/Lower: The back of the frame has a historic pine slat backing that does not fully seal the contents of the frame allowing smoke and moisture to seep into the frame package.
The watercolors exhibited a range of damage:
• Minor condition issues—strong smell of smoke and a fine to moderate layer of soot deposited on the rectos and versos of the artworks• Moderate condition issues— strong smell and heavy soot deposits, minor water stains, planar distortions of the support after exposure to high humidity levels, minimal physical damage such as skinning and tears as works were removed from frames and window mats.• Severe condition issues— strong smell and heavy soot and ash deposits, considerable water staining, strong planar distortions and cockling, scorching, and embrittlement of paper and media layers.
Click the arrows to see examples of the condition issues:
1) Untitled (figure on horse) by Marino Marini, gouache and ink on machine-made, wove paper exhibiting tideline stains in the paper and media. The darkened rectangular area of the paper has been caused by the heat of the fire. 2) Raking light image highlighting cockling and planar distortions caused by water and high humidity levels. 3) Detail of soot and ash deposits.
Conservation of Fire Damaged Paper Works
First, the watercolors were wrapped into special packets that absorb the volatile organic compounds infused in the works and associated with the strong smell of smoke. Each work was wrapped in a folder made of MicroChamber™ paper with a piece of Hollytex™ polyester webbing interleaving to protect the surface of the artwork from direct contact with the folder (fig.2). The folder was sandwiched between MicroChamber™ corrugated paper boards and wrapped in sheets of polyester plastic. MicroChamber™ paper and corrugated board are preservation materials developed by Conservation Resources International LLC that are impregnated with molecular ‘sponges’, such as zeolites [2]. These ‘sponges’ trap damaging, gaseous chemicals. Soot deposits were reduced using dry cleaning methods avoiding the media. Surface cleaning lifts away as much of the particulates and oils in soot that have a loose physical attachment to the paper. Surface cleaning prevents these components from degrading the paper, avoids imbedding the surface soil further into the paper during other treatment steps, and cleans up the appearance of the works. Large deposits of ash that formed cement-like globs on the surface of the art were removed by breaking up the deposits with a scalpel taking care not to disturb the media.
Many of the watercolors were too sensitive to moisture to allow for overall washing of the support. It is possible that the high temperatures during the fire chemically altered the gum arabic binder in the watercolor paints, resulting in increased sensitivity to moisture. However, some reduction of water staining was possible with local treatment. Solutions of deionized water and or chelating agents were locally applied to areas without media to draw out soluble components of stains. Chelating agents are a class of organic molecules that will bond with harmful transition metals like iron, a particularly helpful stain reduction solution in these treatments as iron is a component of soot. Once applied, the chelating solution was cleared with deionized water, removing the bonded iron. Due to the sensitivity of the watercolors to moisture, it was important to apply the stain reduction solutions while preventing the solutions from moving laterally in the paper and possibly solubilizing the media. To control the flow of these solutions, they were locally applied using hydrogels, cotton swab or brush application over a suction platen, and ultrasonic mist applied to works over suction. A hydrogel looks a bit like Jell-o® and is made of cross-linked polymers filled with micro pores. It acts like a sponge that can be molded or cut into any shape and allows controlled exchange of an aqueous solution and solubilized degradation byproducts between the gel and the artwork. The watercolors with cockling and planar distortions from water damage, were humidified overall in a Gore-Tex® packet and pressed between Hollytex™ polyester webbing and blotters under weight to flatten the paper.
Matting and framing of paper works is an important part of conservation because it provides protection from or slows the progress of degradation factors. Conservation grade framing requires stable preservation mounting materials, mounting techniques that properly support the work and are reversable, and a protective microclimate that seals the frame contents. Under normal conditions, a sealed package protects against degradation due to agents of deterioration[3], such as pollution, light, cycling humidity and temperature, and pests. In the case of a fire, acrylic glazing in a frame will provide more protection than glass glazing [4]. The acrylic acts as a better insulator for the artwork and provides some protection against the transfer of heat. Acrylic glazing will melt at high temperatures; however, it will bow outwards, away from the artwork and towards the heat source. Glass glazing is less of an insulator and will transmit heat from a fire to the artwork much more quickly, resulting in scorching. The sealed package will also buffer extreme humidity levels experienced during such disasters. Window mounts provide some protection during a fire and water event by creating space between the artwork and the glazing, helping to prevent the work from touching and adhering to the glazing which could result in more damage. The mount can also absorb moisture entering the frame, slowing its progression towards the artwork. The watercolors from this case study will be mounted into conservation-grade window mats. The mounted works will be sealed between Tru Vue® Museum Optium Acrylic® glazing and corrugated coroplast backing with 3M™ aluminum lined, polyester, acrylic adhesive tapes to provide even better protection of the watercolors in the future.
Condition Issues of the Fire Damaged Paintings
The paintings exhibited a range of damage:
• Minor condition issues—strong smell of smoke and a fine to moderate layer of soot deposited on the rectos and versos of the artworks.
• Moderate condition issues— strong smell and heavy soot deposits, planar distortions of the support after exposure to high humidity levels, darkened and degraded surface coating that had not cross-linked with the paint film, chemical changes to the pigment or oil medium resulting in a shift in color, minimal physical damage to the frame and painting such as localized loss of paint or ground, embrittlement of paper labels on the reverse of the support.
• Severe condition issues— strong smell and heavy soot and ash deposits, strong planar distortions in the canvas or hard support, embrittlement and charring of the support, cross-linking between the degraded and soot-covered surface coating and paint film, chemical changes to the oil medium, insoluble dark or yellowed films imbibed in the paint film, flaking of the surface coating, permanent localized staining from cross-linked products of soot and paint film, scorching of the paint film, heat blisters, severe embrittlement of the paint resulting in loss of paint or ground, and pigment sensitivity due to chemical changes. In the most severe cases, re-construction of parts of the composition would be necessary.
Click the arrows to see examples of the condition issues.
The Effect of Fires on Traditional Oil Paintings and Their Supports
The paintings presented in this case study were executed in oil paint on a variety of supports; in each case, the oil painting had a protective surface coating of either a natural or synthetic varnish. A varnish acts as a protective layer against physical damage and unifies the gloss of paint layers and increases their saturation. Natural resin varnishes have decreased resistance to cross-linking [5] and oxidation, which is not only present during a fire, but accelerated due to the presence of free radicals and light. Synthetic or modern resin varnishes have some increased resistance to oxidative processes and cross-linking due to the presence of free radicals, temperature, humidity, and light. Heat may melt the varnish or cause it to become brittle and flake. The particulates from the fire may cross-link with the aged varnish, increasing its polarity and resulting in a surface coating that is insoluble. It becomes a sacrificial layer between the fire and the paint; and in some cases, does not protect the paint layer from chemical alterations, heat blisters, scorching, and bleached paint films.
All of the paintings studied from this collection were made with oil paint; the majority date from the late nineteenth century to the early twentieth century. The oil medium itself has a specific transition glass temperature (Tg), which relates to the point where the hardened paint film becomes soft. For oil paint, it is much higher than the lower Tg (~25°C) associated with acrylic paint; typically at high temperatures of 107 to 400 °C, the oil medium becomes extremely brittle due to oxidative degradation processes [6]; this results in flake losses and raised paint. The specific oil medium (ie. Linseed, sunflower, etc.), pigments ground into the medium, and additives in the oil paint (present in modern and commercially made paint), may affect the Tg of the paint film due to the metals and/or organic compounds present; therefore, a specific point at which the oil paint becomes glassy or soft isn’t consistent for all oil paints. Despite this, modern oil paints may become glassy as temperatures as low as 40°C.
Recovering and Preserving Fire Damaged Paintings
Similar precautions were taken to absorb the organic compounds deposited with the soot and the very strong odor of smoke; the odor of smoke may include hydrogen sulfide, which is a decomposition reaction between the materials and the oxidation that occurs with the smoke. MicroChamber™ paper was used to wrap the paintings prior to surface cleaning (figs.3-4). Scavengers were made of Evolon™ tissue: the porous Evolon™ tissue held sodium bicarbonate, or baking soda. The combination of baking soda and the MicroChamber™ paper was used to absorb the molecules that cause the odor. The paintings were left in these envelopes for five days; depending on the intensity of the odor, the scavengers or the paper envelopes were replaced. In several cases, this process was repeated after surface cleaning.
The most immediate concern was consolidating embrittled and flaking paint; this was done with either Lascaux Medium for Consolidation™ or 35% (w/v) Aquazol 50™ in deionized water. The consolidant would be applied with a sable brush, and either a soft silicone tipped tool or a heated (~35°C) Willard® Spatula would be used to set the raised paint back into plane. Heat blisters, or raised bubbles of paint, would be addressed if possible after surface cleaning; in localized cases, brittle heat blisters had erupted after the fire and incurred loss, requiring immediate consolidation. For paintings that withstood the brunt of the fire, the paint film was so brittle, that humidification and a non-contact Infrared heat tool was necessary to prevented breaking of raised paint or further loss. For the humidification process, damp Evolon™ tissue was placed on the surface of the raised paint prior to consolidation. The non-contact Infrared heat tool, was used to precisely heat the area of raised paint to 90°F, to allow it to be gently set back into plane with a soft silicone tipped tool. This method was also used to set down large, brittle heat blisters that would otherwise result in loss (fig. 5). Once the surface of the paint was consolidated, the reverse could be cleaned with soot sponges, a dry brush, and vacuum (fig.6).
FIGURE 3. Preparation to wrap the damaged painting with microchamber paper and sodium bicarbonate filters
FIGURE 4. After wrapping the paintings and labels
FIGURE 5. The non-contact IR tool was attached to our dino-lite microscope stand; silicone tips were used to gently set the brittle bubbles in place
FIGURE 6. Left: Before consolidation Right: After Consolidation
Solubility testing was carried out on the darkened, brown film that covered most of the paintings; in some cases, the film was white due to fire retardant. Testing was done with aqueous, solvent-based, and gel methods [7] here to determine the solubility of both the thick soot and grime layer. The heavy soot and grime are not soluble in aqueous methods containing adjusted pH, chelators, or delivered as a gel (which provided a longer working time). Emulsions, or a combination of water and solvent, was also attempted. It is removed by undercutting the charred and degraded varnish layer with solvent based-methods; depending on the type of varnish, this involved either 1:4 Ethanol:Shellsol, 4:1 Ethanol: Shellsol, Xylenes or alternate aromatics, and free acetone rolled gently with a cotton swab.
Beneath the layer of charred varnish, there remained a thin-yellowed layer of cross-linked surface coating and paint. This was identified with UV light; further organic testing was not done to determine the organic and insoluble yellowed product. It is estimated that the prolonged time the soot interacted with the surface of the painting allowed constituents from the fire and the paint film to interact, cross-link, and become nearly insoluble. In addition, as the level of heat and relative humidity increase, the paint film swells and allows materials to become permanently imbibed in the paint. Removal of this insoluble and imbibed material may require swelling the paint film. This may be considered an appropriate risk; however, with modern oil paints, there are associated risks with pigment removal. Solvent gels were tested to: 1) slightly swell the oil paint to remove the cross-linked products and 2) prevent solvents from affecting paint layers below the treated surface. A solvent-based gel worked well since less mechanical action from a cotton swab is necessary, especially in areas of impasto. A Pemulen TR-2™ gel was tested to swell and removed the remaining thin layer of discoloration; either a 1:4 Ethanol:Shellsol or a 5% (w/v) Benzyl Alcohol gel in Pemulen TR-2™ was used to remove the yellowed layer (fig. 7). This could be cleared with deionized water, and in localized cases, was followed with a solution of 1:4 ethanol:shellsol. There was remaining discoloration (fig.8) that would need reintegration through retouching (fig.8).
Traditional methods were used to integrate remaining insoluble staining from the fire [8]. This included filling material, Paraloid™ B72 retouching gels to recreate impasto, and Gamblin®Colors for Conservation.
FIGURE 7. Detail of cleaning the remaining cross-linked, yellowed layer
FIGURE 8. Some areas were permanently stained; removal of these stains would incur further damage to the paint film and would be reintegrated through retouching
General Recommendations for Owners in the Event of a Fire
Emergencies are high stress situations that can be chaotic and dangerous, impairing the ability to calmly make rational decisions [9]. In order to effectively respond to a state of an emergency, it is important to have some form of emergency preparedness plan [10] designating response procedures. Collecting institutions have emergency preparedness plans as one of their core documents to ensure responsible stewardship of their collection. It is possible for individuals to develop their own form of an emergency preparedness plan to ensure personal safety and protection of their collections.
Some precautionary measures that may facilitate recovery efforts after an emergency, include: a list of your collection highlighting the most important pieces to indicate salvage priorities and a floorplan identifying general locations of the listed items to help first responders form their emergency plans. These lists should be kept in a secure location with a second off-site location such as a safe deposit box or a personal, secure cloud storage service. As was explained in the case study, photographs of collection items visually record their condition and can serve as a reference after damage has occurred. Annually reviewing your list and any corresponding emergency plans is important to ensure that it remains relevant and effective.
Personal safety is the highest priority
. In the event of an emergency, ensure that all persons are safe and do not re-enter an emergency site until first responders have deemed it safe. Before entering the site, create a plan for recovering items and wear the appropriate personal protection equipment, like masks, gloves, safety glasses, a hard hat, and boots. Part of your plan for recovery should include consulting a conservator to be sure that you are handling collections safely. Take breaks, hydrate, and stay nourished to remain refreshed and alert, avoiding fatigue-induced mistakes and injury.
In the case that your institutional or private collection is affected by the devasting changes from a fire, here are some measures that may be taken after the fire is managed by fire fighters:• Contact a conservation specialist immediately; no matter what the material may be, the deposits from the fire may cross-link with the surface over a short matter of time and become more insoluble and difficult for the conservator to remove.
• Place the object flat and upright in an open box; if it needs to be moved or travel after a fire, any potential loss will be contained in the box. Sachets of sodium bicarbonate or baking soda may be placed in the box to help absorb the smell of smoke.
• Do not touch the object or try to clean the soot yourself; in our case study, areas of brittle and vulnerable medium were obscured by soot and could easily be lost due to contact.
• Depending on the severity of the fire, place air filters in the room if the art work is still hung on the wall; do not allow commercial companies to deodorize the room with scented fumigation and consult with a conservator if your insurance company recommends them.
• Do not allow companies to fumigate the area with chemicals that will deodorize the smell of smoke; consult with a conservator first. These chemicals may cause unwanted deposits or changes to the surface of your artworks.
• If water is introduced to the object:
• Do not allow commercial companies offer mass freeze drying or chemical drying processes before consulting with a conservator to determine what can and cannot be dried in this manner.
• The structural integrity of objects is compromised when they are wet, damp, or embrittled from the heat. Ensure that you are handling them as carefully as possible:
• Do not hold objects by handles or other attachments as these are the most vulnerable and most likely points to break.
• Do not touch surfaces with media or photographs.
• Paper works are particularly vulnerable as they can tear or be crumpled if not supported. Use clean trays or basins to support unframed paper-based works during transport.
• Paint on hard or canvas supports is vulnerable to flake losses due to either warping of the hard support or shrinkage from water damage to the textile support. Be aware that certain materials such as textiles can become waterlogged increasing their weight, putting more strain on the weaker areas of the object and making them more difficult to handle.
• If it is safe to do so, unframe framed works to increase drying rates. DO NOT unframe any works that appear to be touching the glazing as this will result in further damage. DO NOT unframe anything if you are uncertain about the safety of the object during the process. Instead, consult a conservator for advice.
• Mold growth is a concern for organic materials and will grow within 48 hours if objects remain damp.
• Create a clear, clean drying space either on a floor or on tables. Use materials like paper towels, unprinted newsprint, blotter paper, or clean terrycloth towels to line drying surfaces to help wick away moisture from objects. Change these materials periodically to increase drying rates and discourage mold growth.
• Consult a conservator to understand if any special precautions should be taken for certain materials that may dry more quickly than others causing warping cracking, flaking etc.
• Place objects onto drying surfaces separating items that can be separated without causing damage.
• Create air flow with fans facing away from the collection items and install dehumidifiers to help reduce humidity levels.
• Rusting and corrosion is a concern for metal objects or metal components of objects.
• Dry metal objects with a clean paper/cloth towel careful not to rub the towel over the surface as this may cause scratches.
We continue to treat the works that are part of this collection and hope that a fire never happens in your home or institution---- it is devastating beyond the needs of your collection. However, we want you to know that in some cases, all may not be lost and to feel comfort in that a conservator is ready to help.
REFERENCES
[1] Degradation products are often related to the materials and techniques used to create an object; it is understood as inherent vice with respect to the medium, support and the way these materials were used by the artist. Degradation products may also arise from environmental conditions and physical damages from accretions.
[2] Rempel, Siefreid, “Zeolite Molecular Traps and Their Use in Preventive Conservation”. WAAC Newsletter. 01/1996.
https://cool.culturalheritage.org/waac/wn/wn18/wn18-1/wn18-106.html.
[4] Phibbs, Hugh and Hann Lanford, April. “Protecting Framed Works from Heat and Smoke”. Quicknotes Newsletter. Tru Vue®. 04/2015. https://tru-vue.com/2015/04/protecting-framed-works-from-heat-and-smoke/
[5] Cross-linking is the process where the polymer chains in the varnish link
with each other due to reactions with free radicals. The more they link, the more insoluble they become.
[6] Izzo, Zendri, Biscontin, Balliana. " TG–DSC analysis applied to contemporary oil paints". Journal of Thermal Analysis and Calorimetry. 03/30/11 https://link.springer.com/article/10.1007/s10973-011-1468-y
[7] A gel may contain a thickening agent and either a solvent or aqueous solution. It is hygroscopic in nature and may prevent unwanted contact with paint layers below the target of removal or provide longer working time for a solvent.
[8] No samples were taken from the paintings to determine the organic composition of insoluble stains left by soot and the decomposed varnish and paint film
[9] Black, Jerzell. “This is your Brain on Emergencies”. Public Health Matters Blog. Center for Disease Control and Prevention. 11/07/2016. https://blogs.cdc.gov/publichealthmatters/2016/11/this-is-your-brain-on-emergencies/
[10] American Alliance of Museums. “Ethics, Standards, and Professional Practices: Disaster Preparedness and Emergency Response Plan”. Accessed: 09/23/2020. https://www.aam-us.org/programs/ethics-standards-and-professional-practices/disaster-preparedness-and-emergency-response-plan/
