PRECISION LOW-STRESS HEAT TRANSFER IN ART CONSERVATION

Conservation treatment methodologies have historically exploited heat as an essential factor for the effective remediation of structural damage in paintings on canvas, works on paper, and other artworks.  However, past interventions were not without risk, since heat was applied with rudimentary tools that provided quite limited control over the set temperature, the steadiness of delivery, and uniform distribution over treatment surface area, leading to highly undesirable results ranging from uneven or incomplete treatments to irreversible changes in surface morphology of the paint and ground layers.  In fact, the examination of paintings on canvas with prior lining treatments often involves identification of visual evidence of unfortunate mutations that may be attributed to the effects of uncontrolled and excessive heat transfer, pressure and moisture. This is true of flour paste linings conducted with hand held irons, but also wax resin linings conducted with hot tables used in mid-20th century, and even thermoplastic synthetic linings conducted from the 1980s to present. From a theoretical point of view, the approach of minimal intervention has fully matured as a standard and goal, yet technological advancements of heat transfer instrumentation have lagged far behind, leaving conservators without the precision means necessary to refine their treatments. 

 

In our research and studio practice, we all seek to refine our treatments to be more effective while reducing the risks.  But the concept of minimal targeted  intervention remains an ideal without treatment options that allow us to actually control the major treatment factors, such as temperature, pressure and moisture. Among these, heat transfer plays a particularly important role. Traditional oil paints and modern polymers, wood,  canvas, and many other artistic materials display significant viscoelastic effects. In some cases and  treatments even a small viscoelastic response can be significant. The combination of accurate control over time, temperature and humidity allow for the manipulation of the Young modulus during the treatment of painting materials and interventions within the “safe zone” of viscoelastic dynamics and margin of minimal risk

 

Heat transfer is an essential tool in many conservation treatments of paintings, paper and other artworks. Many common treatments that aim to consolidate paint, flatten deformations, attach lining and more wouldn’t be effective at room temperature. However, heat transfer cannot be fully and safely exploited without due control. Lack of control is the essence of the old problem, which is particularly relevant when treating extremely fragile modern and contemporary materials. In the context of the evolving use of precision low-stress heat transfer in structural treatments of paintings on canvas, our research and treatment practice contributed to the design features and practical applications of a precision heat transfer technology that was developed specifically for art conservation in response to this critical gap in currently available instrumentation.  Flexible silicone-clad heating mats provide the conservator with unparalleled control in terms of accuracy, steadiness and even distribution in the low temperature range (below 40C) up to those used customarily (to 70C).  The precision control, combined with a flexible and thin profile, allows conservators to formulate innovative treatments of both lined and unlined paintings.   

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The research (see publication) and conservation treatments, using precision heat transfer  mats with mild heat transfer for minimal lining and structural treatments of diverse paintings conducted over a 15-year span (2003-2018). Since 2003 multiple advances to the design and new nanomaterials have radically expanded their technical capabilities, resulting in safer and more nuanced treatments. The operational parameters and practical advantages offered by the new warming nanotechnology and targeted approaches taken in each particular treatment show the broad versatility of the new method and how easily it could be tailored for the specific needs of each particular case, opening new opportunities for art conservators to refine their treatments within the margins of minimal intervention and risk. We and the entire group of conservators involved in the research and treatments see a lot of value and potential in Mobile Accurate Temperature approach and applications, the first letters of which actually could be read as MAT. As conservators we always wanted a tool like MAT for our own work and we welcome collaborations and sharing knowledge aimed to develop new treatment methods with others.