Paintings submitted for treatment first undergo a condition assessment to chart their state of conservation. Analytical tools such as ultraviolet and infrared photography, x-radiography, and multi-spectral imaging are routinely utilized.
Subsequently, the client is provided with a condition report along with recommendations for any proposed treatment, the estimated cost, and time to complete.
The documentation of the treatment is available upon completion of the project.
The history of picture cleaning goes back many centuries. There are many old records with "recipes" for cleaning that range from the exotic and bizarre to ordinary substances such as spit. Today, picture cleaning has become a science. The cleaning of Michelangelo's frescoes in the Sistine Chapel is a well known illustration of this. Museum laboratories undertake cleaning no longer as a matter of routine. During the removal of accumulated dirt, old varnish, and non-original repainting, we are fully mindful of every key consideration - ethical, technical and scientific.
Structural work on the support
Paintings have been created on a wide range of supports: canvas, wood panel, parchment, metal, etc. Each requires specific corrective action when structural integrity issues are present. Such issues may range from canvases becoming brittle or perforated, wood panels split, warped, or damaged by insects, or corrosion of metal panels. Degradation of the support can be due to a combination of the effects of age, environment or handling.
We are equipped to carry out complex structural repairs on wood panels and lining of canvases up to 2 by 3 meters ( approx. 6 x 9 ft) in size.
Paintings are complex physical and chemical constructs. In cross-section, a painting is a sandwich of layers - support, ground, underpainting or drawing, with strata of paint and varnish. Each one has distinct patterns of behaviour and reaction to the environment. When adjacent layers are incompatible due to physical or chemical factors, destructive processes may occur. These are primarily evident in delamination, cracking, etc. In taking corrective action, we consolidate lifting paint by reattaching and securing the separated layers in the course of lining or localized work.
As with the issues surrounding cleaning, approaches to retouching are similarly steeped in controversy. Paintings more often than not ended up being "beautified" or "completed", according to the prevailing taste. We retouch only to the extent that the final result gives a sense of cohesiveness. Depending on the painting's age and condition, damages are masked to the threshold where they do not detract from the enjoyment of the original work while permitting the correct understanding and interpretation of the artist's original intent.
Varnish fulfills several functions on a painting. An isolating varnish can be first applied as necessary prior to retouching. The final varnish is intended to saturate the paint layers, to impart a desired surface gloss, and also to protect the surface.
The choice of varnish and the method of application is to be in keeping with the painting’s surface properties and aesthetic considerations based on the period.
An acceptable varnish is stable, colorless, and removable without damage to the painting.
Photography and multispectral imaging
Visual examination with magnification and diverse modes of illumination reveal many aspects of a painting.
However, there is much the human eye cannot see. Ultraviolet fluorescence techniques (UVF) are typically used to render old restorations and foreign substances on paintings visible. Reflectance imaging techniques in the ultraviolet provide visualizations of multiple and different varnish layers, and infrared reflectance can provide information about underdrawing and changes in design.
In our laboratory, these diverse techniques are combined into one overarching method – that of automated multispectral imaging that encompasses the ultraviolet, visible and near infrared parts of the spectrum in one pass. With micrometer resolution, a full scan can reveal a painting's entire conservation history.
These services are provided in the studio by Peter Paul Biro.
Pigment and medium analysis
During conservation treatment, a painting can also be examined by Raman in-situ. Together with polarized light microscopy, this is our preferred method of materials analysis.
Raman spectroscopy has the advantage that it requires no sample removal or preparation – it is a noninvasive method.
Other analytical methods include:
FTIR– Fourier transform infrared spectroscopy
EDX – Energy Dispersive X-ray Spectroscopy
SEM – Scanning electron microscopy: provides information about the topography and infer composition of the sample with a magnification up to 500,000 x
X-Radiography - Reveals the stucture of the painting including original alterations to the design as well as losses and repairs
Framing and gilding
Although we have accumulated a lifetime of experience working with frames from all periods, we only undertake minor frame repairs, including gilding and some structural work. Major repairs are sent to qualified craftsmen with whom we have an established working relationship.
Paintings, like all cultural artifacts, face a variety of threats: damage due to accidents or emergencies , pests, pollution, or the adverse effects of humidity, temperature, and light.
Some of these sources of danger are controllable through the implementation of procedures which enhance the safety of paintings and extend their lifespan.
We provide advice in the following areas of particular concern:
Environmental: air quality, humidity and temperature control
Lighting: controlling the type and intensity of exposure or distance from light source
Handling, packing and transport