Capabilities

Each painting presents unique questions. The methodologies we employ to glean evidence must therefore address the uniqueness of each case.

All cases begin with exploring the conservation history of the object. We must first determine what happened to it over decades or even centuries of its existence. This first step is fundamental because, when forensic evidence is found, we must be certain that it is part of the original painting - the intended and original creative process - and not a result of a later restoration and handling by hands other than the artist’s. In order to accomplish this, we employ such techniques as hyper-spectral high resolution digital imaging from short wave ultraviolet to the near infrared region of the spectrum.

Concurrently, spectroscopy is carried out on the surface being investigated, as the combination of these techniques - imaging, spectral imaging and reflectance spectroscopy - provide powerful verification as to whether a connection between the forensic evidence and the substrate are linked to authorship or not. Investigation of material composition and understanding of the material structure of the work of art are also basic to the authentication/attribution process. Detection of substances not available to artists at the alleged date of creation of the object is a vital tool in the discovery of misattributions and forgery.

We implement a broad range of examinations prior to any analytical work to understand the painting’s conservation history. Our concentration is on the correct and appropriate selection of methodologies. Coordination with an ongoing conservation treatment of the work is also essential.  Sampling is undertaken only when we are confident that no contamination or anachronistic substances are introduced into the analytical process.

Depending on how the analyst approaches the problem and how he prepares his samples, his work can produce erroneous data. The sampling procedure has to take into consideration the fact that surface contamination as well as anything intentionally deposited on the surface or permeated into the body of the paint layer can become part of the analytical result. Permeation by chemicals used to treat old and brittle paint layers may be present and will now appear as integral to the paint sample analyzed. If the analyst is not aware that prior interventions such as conservation/restoration had taken place with unknown and necessarily later substances, the results will present anomalies.

The above photomicrograph illustrates this well. The red and bluish particles indicated by the arrows represent the top of the sample surface.  The other particles reveal the subsurface structure of the paint samples. Had this painting been varnished, or otherwise treated with materials not available at the time of creation of the work, and if that were overlooked, this painting could well be rejected as a ‘modern fake’.
The illustration below shows two FTIR spectra of two sides of the same pigment particle in another sample. The spectrum on the top shows the organic composition of the internal portion of the particle. The spectrum below shows the organic composition of the particle’s top surface. The two spectra reveal two completely different substances.

The documents below illustrate the efforts by Lee Krasner, Jackson Pollock’s widow, to have conservation treatment performed on two of her late husband’s works. As can be seen from the documents, the materials used in the course of the treatment were applied at least two decades after the paintings had been created, and may or may not have been available in the artist’s lifetime.
Later analysts can be misled by just such occurrences as described above. 

Certain other analytical methods such as GC-MS and pyrolysis consume the entire sample including whatever contamination or later additions of foreign materials to the painting. In essence, poorly planned sampling can produce unreliable and misleading results. In addition, the choice of sampling site and quality of sample taken is entirely at the discretion of the technician. In essence, the technician can influence the outcome of the test producing erroneous results though the analytical work itself appears to be scientific and correct.

Fingerprint  evidence

On the left: Detail of a painting, taken with what is widely used equipment by police forensic examiners. On the right: Image taken of the identical area. Our hyper-spectral scanner reveals a clear fingerprint hiding in just 10 nanometers of the spectrum. The conventional equipment reveals nothing in the same area.

The use of fingerprints for identifying an individual is a well-established practice accepted worldwide. When such evidence is found on a work of art, understanding the connection between a fingerprint left in paint and the painting itself can shed light on who created it. Our primary focus is to detect, document and interpret forensic evidence on works of art. This is a non-invasive and non-destructive method as the process must respect the integrity of both evidence and artwork. We employ a wide range of established methods of investigation and analysis. Many of our cutting-edge techniques and key instrumentation were developed and built in-house to address specific cases. Our research efforts, collaborations with scholars, experts, and technicians across many disciplines have resulted in acclaimed discoveries over the years. A number of these have been reviewed in the international media and presented in peer reviewed journals and lectures. The roster of our clientele extends from museums to private collectors.

Due diligence has become a necessary and key part of buying and selling art. There are many examples of how things can go wrong when research is incomplete. Perhaps the most pertinent illustration is the recent case of a Leonardo da Vinci drawing in which a previous owner sued an auction house years after the sale for not having carried out sufficient testing or research. Real treasures can slip through fingers all the time for lack of proper studies. As well, forgeries are traded sometimes  innocently by uninformed owners. These situations can result in years of headaches, litigation, and distress. As restorations and alterations to the artwork commonly go undetected, owners approaching art historians for expertise without proper conservation assessment are often frustrated by informal dismissals.

Summary

Our emphasis is always placed on non-invasive analytical methods wherever possible. Physical removal of any material (sampling by chipping or scraping) from the artwork, no matter how small the sample, is something we believe is a method that is becoming a thing of the past. We perform it only as necessary.

Our analytical tools include:

• Numerous methods in optical microscopy and micro-imaging

• Narrow band hyper-spectral imaging, image cube mapping of materials

• In-situ micro-spectroscopy • Recovery of fingerprints, comparison and verification

• Recovery of DNA, mtDNA and aDNA evidence

• FTIR (Fourier Transform Infrared Spectroscopy)

• SEM-EDX (Scanning Electron Microscopy – Energy Dispersive X-ray spectroscopy)

• Digital image processing, development of custom algorithms

• Raman spectroscopy and Raman imaging

With respect to services such as X-ray, DNA, mtDNA, aDNA, dendrochronology and Carbon14 dating, these are contracted to leading consulting laboratories.