Forensic_ analysis also offers critical insights into a painting’s style and physical composition. Even if a forged painting is made using authentic materials, forensics can reveal anomalies in its content or other features. For example, a forged Titian can be eliminated if the paint’s copper content does not conform to established parameters, which is possible even if the forger had used the correct types of paints. Basically, there are two types Of forensic analysis. The first one involves photographic techniques that use infrared, X-ray and ultraviolet light.
This is the most common form Of scientific test, but its major weakness is that it does not study actual samples. Infrared Refractory’s identifies markings or drawings underneath the painted surface. In the old masters, under-drawings were often drawn directly on the canvas as a sketch for the painting. Examining under-drawings can help to establish the painting’s authenticity and can be compared against the artist’s style, This radiation can also detect authentic signatures indistinguishable to the naked eye, or reveal fake signatures that were added after the completion of a forgery.
Infra-red light lies just outside the visible spectrum, It overlaps with the red area tot the spectrum and the microwave region. Conservators use wavelengths tot radiation from the near infra-red part of the spectrum CLC mostly in the range of 75002000 manometers. This relatively long low frequency wavelength is able to penetrate through the upper layers off painting or work on paper, such as oil paint, to the drawing underneath. An intra-red reflector is created by capturing an image of the infra-red wavelengths that are reflected into a camera lens.
Infra-red examination is commonly used to look at an artist’s working technique. It provides clues as to how a work Of art has been constructed, and Often gives an indication of the materials that the artist used. As some paints and varnishes can appear transparent in infra-red light, details hidden beneath the surface may be revealed. Graphite pencil, charcoal lines and other carbon-based drawing media used during the early stages of developing a work of art are enhanced using infra-red refractory’s.
X-ray photography uses short-wave radiation to detect alterations in a painting, areas of a painting that have been repaired or changed and also identity certain types of X-ray absorbing pigments, like lead white and led-tin yellow. Since dates when these paints were introduced have been determined, their presence can shed light on the painting’s time of execution, Coupled with XIV light analysis to reveal areas of in-painting these techniques can aid in the identification of pigments. However, though X-ray photography is able to detect lead-based paints, it cannot quantify the paint’s precise lead content.
In addition these technologies are incapable of analyzing organic material such as the binding ingredients in paints. This means investigating a painting through photographic examination alone can reduce highly deceptive results, and they must be employed in tangent With additional tests to properly assess a painting. The second (and more effective) category of scientific testing involves the extraction and analysis Of samples from a painting. The most advanced method is Reflection X-ray Fluorescence Spectrometry Analysis (TEXT), which examines pigments taken from a painting using X-rays.
The extraction process involves obtaining a micro-sample by brushing a cotton swab over the surface of a painting. The sample is then subjected to high-intensity X-ray radiation, automating the chemicals in the sample and causing them to release secondary X-ray signals. Each element in the sample emits a unique signature, revealing the precise elemental contents of the sample. TEXT examination differs from other photography techniques because it involves the analysis tot actual paint samples rather than Nan-intrusive photography.
Thus it can produce far more detailed forensic chemical reports compared to non-intrusive photography. According to scientists R. Clockmaker et al, “a characterization of the pigments may help in assigning a probable dateћ. To the painting. This is because each type of paint has a unique chemical composition which is traceable to the time it Vass introduced gore example, Prussian Blue was introduced in 1710. Therefore, if a painting attributed to Rembrandt contains Prussian Blue, it can be immediately dismissed as a forgery, However, there are also more intrusive forensic analysis techniques that require paint samples.
These methods are very effective, but are considered unacceptable to many galleries because they cause a small amount Of damage to a work. One such test is the Atomic Absorption Spectrophotometer (AS) test. Lab samples for AS can be carefully cut from the back side Of a painting, but although it is a destructive technique, the sample size needed is very small (typically about 10 milliards). Solid samples are then dissolved, often using strong acids. A minute quantity of the liquid sample solution, about 0. 0100. 02 the size off raindrop (20050 is sprayed into a nitrous oxide. Acetylene or air-acetylene flame, which vaporizes the solution, releasing metal atoms from their chemical compounds and converting them into their elemental forms. A beam of light passes through the flame, and some of the atoms in the sample pour absorb energy from this light. Light shone through the flame is of a suitable wavelength for a particular element, and some of this light is absorbed by the atoms tot the sample. A detector on the other side measures the intensity Of this light, and records the results. The results obtained would reveal the concentration of the element in the solution, and thus in the original painting.
Each chemical element in the sample requires a different lamp that emits the characteristic wavelength of light that the element can absorb, which means the elements in a sample must be tested one at a time. To increase the precision f the measurements, laboratory technicians compare the results with a series of “standards”, solutions with known concentrations of the element of interest. Often, they account for interferences from the other chemical elements in the samples by running “matrix standards” that simulate the bulk characteristics of the corresponding unknown samples.
Flame AS techniques are the oldest methods, measuring parts-per-million element concentrations With accuracies in the 1-3% range. Graphite furnace AS, uses much smaller samples, making parts-per-billion measurements With about 20% accuracy. The newest technique, diode laser AS, looks at several elements in a sample simultaneously using an array of lasers that emit various wavelengths of light. A mathematical process is then used to separate the mixture of light wavelengths that reaches the detector.
These are used to detect materials that do not conform to the standards of the time and place off painting and/or chemical anomalies in it. Like the TEXT test, these methods analyses trace elements in paint and can determine whether the paint was produced after the work was supposed to have been made, Other techniques include the study of carbon-based binders such as oil and glue seed in paint media, which can be dated according to their carbon-14 content . Scientists have also developed a new method capable of accurately determining the age of the paint film itself, which was previously impossible via the standard carbon testing method.
They can cross-reference these tests with DNA analysis of organic matter used in painting , tracing these components to their places of origin. Although the aforementioned techniques are crucial in determining the authenticity of a painting a painting cannot be considered authentic without both forensic and stylistic analysis. However, claims that a ‘trained eye’ is sufficient to authenticate a painting are simply untrue, as one cannot detect carbon-14 content, lead isotopes or Other chemical anomalies unique to particular painters by looking at a painting.