Mild heating and diverse thermal treatments are very widely used in art conservation and are among the most common in various areas of the profession, and constitute the core in the success for most structural treatments, such as consolidation, treating planar deformations, reinforcing degraded support, lining and others. Thermal treatments as a rule involve other means of treatment such as water vapour, pressure, introduction of an adhesive, creating optimal conditions for a specific enzyme etc.
|Severe delamination and cupping paint film in a painting on canvas support|
Artworks are unique cultural objects, often of great aesthetic, historical or cultural value and are irreplaceable. Any conservation treatment involves great responsibility for the integrity and for the authenticity of the artwork or other cultural heritage asset in treatment. Artworks are often composed of heterogeneous organic and inorganic materials that can be inherently particularly fragile, often incompatible with each other or of a limited lifespan. They can be particularly sensitive to various physical and chemical factors that are applied in diverse conservation treatments, such as moisture, low pressure, changes in temperature and more, which, if applied incorrectly may have damaging effects on the artwork.
"Smart" heating mats can provide the accuracy, versatility, mobility and control over the temperature meeting the highest up to date conservation standarts.
Lack of control over heat in particular could damage the artwork irreversibly. Therefore, highly accurate temperature applied uniformly and selectively and the possibility to control the placement of the source of heat are of great importance. Throughout the history of conservation we can trace various attempts to design methods that would reduce the risk from uncontrolled heating to a minimum and gain the desired control over the heating source. In all thermal treatments highly accurate, uniform and steady temperature, which could be applied selectively, is crucial, and a lack of control over the temperature has led to incompleteness or failure of the treatment, and irreversible damage to the artwork. Difficulty in controlling the temperature and distributing the heat evenly increases with the area of application, and when using currently available instrumentation, even in relatively small areas, accurate application is problematic, and overheating occurs. Precise control is particularly problematic in treating medium and large-scale artworks, or where accurate constant temperature is required for a prolonged period. Essentially this problem arises from the lack of accurate, efficient, versatile and economically accessible instrumentation, meeting the needs and standards of conservation.
Thermographic image of a 1990’s multipurpose low pressure heating table in current use, showing uneven heat distribution and temperature fluctuation
The IMAT project responds to this critical omission in current treatment instrumentation for accurate, selective and mobile devices for mild heating, which is essential for success in most structural treatments of paintings, works on paper, textiles and other cultural heritage assets. In the IMAT project the application of carbon nanotubes as well as other conductive nanomaterials for mild heating offers new opportunities to design radically new highly accurate mobile mild heating technology and devices - in the form of multifunctional flexible “smart” mat heaters - with desirable qualities for art conservation. Such heating mats fitted with the to-be-designed sensors and controls could be designed in ultra-thin, soft, transparent, and woven forms, and may be designed as gas permeable membranes to permit the migration of vapours and airflow so often used in combination with mild heating in conservation treatments.
IMAT heater is designed to allow for the even heat distribution and hilghly accurate temperature control
IMAT project offers to cultural heritage conservators new technology and devices with the radically new technical characteristics. The major IMAT features are as following:
Conceptual design of IMAT TP – transparent and breathable (perforated)
To further improve the performance of the IMAT, it will be designed in three different types, which will reflect the needs of specific applications in conservation.
1. IMAT-S or “standard” will be conductive highly accurate low voltage mobile heater with soft and non-tack surface, which will be opaque and non breathable. The IMAT-S is intended for the thermal treatments where visibility and breathability are not required. Can be manufactured in large formats and the operating temperature is 20º-70ºC with the maximum of 85ºC.
2. IMAT-B or “breathable” will be highly accurate conductive low voltage heater, which will be opaque and permeable to gases, in particular to airflow and to water vapours. The IMAT-B will be designed by combining an air permeable hybrid textile, a conductive nanomaterials coating, and a gas permeable membrane (airflow and water vapours) that is impermeable to water. The maximum size will be 60 x 40 cm and the operating temperature will be 20º- 45ºC with the maximum of 55ºC.
3. IMAT-T or “transparent” will be conductive low voltage heater, which will be transparent or translucent, but not breathable or permeable to gases. However, a perforated variation, the IMAT-TP (P – for perforated) may be tested, in an attempt to make a heater that is both transparent and breathable. The maximum size will be 60 x 40 cm and the operating temperature is 20º- 45ºC with the maximum of 55ºC.
The IMAT heater’s thin profile allows it to be easily inserted under the stretcher or “sandwiched” with other materials used in diverse structural
IMAT is a unique novel mobile mild heating device that could be used in diverse areas of conservation.
In paintings conservation the new mild heating device (IMAT) may be used in treating diverse deformations and planar distortions, to reduce cupping and distortions to paint film, tear mending, consolidation of paint layers, reinforcement of degraded supports in diverse lining and backing treatments. Air permeability combined with highly accurate and stable mild heating at low temperatures will offer new opportunities for minimal intervention in treating planar distortions, improvement of the condition of earlier treatments, and more. The material of choice needs to exhibit low adherence (a non-tack surface) and high resistance to physical and chemical factors associated with various conservation treatments. The IMAT heater’s thin profile, flexible nature and availability in a wide size range are well suited for use in treating works on the stretcher. It may be used with all currently used conservation adhesives and may be incorporated into either traditional or recent methodologies where controlled mild heating is required. Optical properties, such as transparency, would be highly desirable for visual control during treatment, especially when the heat source is applied to the recto. IMAT could find its application also in aesthetic treatments, such cleaning of painted surfaces with enzymes, which require very precise and specific temperatures of application, and which must stay constant during the treatment. The IMAT would be particularly useful for in situ work, and in emergency response actions.
IMAT would be most useful in all structural treatments, where accurate mild heating is one of most often used means of treatment
In paper conservation the IMAT could be used in treating planar distortions and in consolidation treatments, where mild heating is required. The combination of highly accurate temperature control and permeability to gases, such as airflow and water vapours, as well as transparency would be a strong asset in many humidification treatments. As in paintings conservation, the new heating device will find its application in enzymatic cleaning treatments, which are frequent in paper conservation. Yet another application could be thermal disinfection treatments.
In textile conservation the IMAT could be applied in methods similar to those implemented in painting or paper treatments, used for consolidation, smoothing planar distortions, using enzymatic methods of cleaning and more. An added advantage of the device would be the option of placing the heat source simultaneously on both sides or on either side, as well as performing the work in sections on large pieces. Yet another application could be thermal disinfection treatments.
In 3-D objects IMAT heaters of diverse configuration and shape could be applied in consolidation treatments. These could be quite useful for polychrome sculptures, frames, furniture, mixed media objects and more.
In other applications the availability of this new mild heating technology and the programmed field testing will allow conservators to find additional applications and ways of incorporating its use into both current treatments, and new methodologies that have yet to be developed. For example, developing and advancing other conservation tools where mild heating is required, such as heated syringes, heated spatulas, soft heated tips and other.