Art Dating

Art Dating, Art Age, Forensic Authentication, Authenticity

Art Dating Experts

Forensic science doesn’t authenticate art, alone. Instead, it can be used to provide insight as to when the art piece was likely made as well as determine the composition of the materials used in its production. Art Dating, Art Age, Forensic Authentication and Authenticity are all possible through the proper use of forensic science and provenance.

The forensic examination of art begins from a point of complete neutrality. The art is examined using state of the art equipment to analyze the materials as well as to determine whether there is any indication of fraud through artificial aging, forgery or copying.

Mr Stewart has been called upon to forensically examine many different types of art, historic constructions and sculptures to include pieces of Nok Terra Cotta, Mammoth Ivory, and Brazzerville and Songye Tribal Horns as well as various paintings to include possible works by Dahl, Picasso, Popova, Kandinsky, Cezanne, DeKooning, Van Gogh and Hopper. Porcelain pieces can also be tested using the same approaches.

Ultraviolet and infrared fluorescence and luminescence are useful in determining whether a piece has been brought into contact with extraneous chemicals to induce artificial age as well as to better examine for normal aging characteristics, repaired damage, etc.

A High Resolution Video Spectral Comparator can be used to examine the piece with various forms of electromagnetic radiation and filters. Following are examples:

High resolution digital photographs can yield additional information for the forensic examination. Following are some examples at 50x and 100x magnification of questioned mammoth ivory and a clay sculpture:
Art Dating Mammoth ivory 1
Art Dating Mammoth ivory 2
Art Dating Mammoth ivory 3
Art Dating Mammoth ivory 4

Art Dating Example

Porcelains can also be tested forensically. Digital images can yield information regarding the glazing, method of construction and aging characteristics. Following are a few examples:

Xray Fluorescence Spectroscopy (XRF) has greatly advanced in the past few years to the point that an art piece can be examined without causing any harm or damage to the composition. Samples no longer need to be removed and the piece can be tested locally. XRF yield information regarding the inorganic composition of the piece. This is important in reaching an opinion about age or origin. Clay samples can be compared to determine if the clay source was different. Paints can be analyzed to determine whether chosen pigments were typical for a particular artist as well as available during a particular period.

An example would be with white oil-based paint. Mass production of titanium white paint for artist’s oil began in 1922. Lead white paint was often the choice prior to the 1920’s. Lead has widely been known to be toxic since the late 1800’s. Once its toxicity was known, the use of lead in manufactured artist’s paints began to be restricted resulting in the availability of the paints dissipating shortly thereafter (early 1900’s) especially when titanium was introduced for white paint in 1922. XRF can not only tell the examiner whether the art contains inorganic components, e.g. titanium or lead, but it also can determine the concentration. This can be useful when an artist is known to have mixed various paints to achieve particular colors. It is also useful in determining whether the titanium, for instance, is due to the soil or quartz found in the clay (in the case of a porcelain) or else from the glazing material or paint. Individual areas are separately tested allowing for a close determination as to the source of a particular inorganic component. Iron, lead, titanium, silver, gold, cadmium, cobalt, chromium, zinc and numerous other elements can be analyzed using state of the art XRF equipment. The presence or absence of the inorganics is critical in addressing the age or authenticity of a piece of art, whether it be a fine art painting, construction, or porcelain piece. Even the composition of the nails or tacks can help date a piece.

Zinc yellow (lemon yellow) contains zinc and has been used in paints since around 1830. Naples yellow contains lead and has been in use in paints since the sixteenth century. Cadmium yellow has been used in paints since 1820.

Vermilion red paint was used between 1300 and 1900 and was widely replaced by cadmium red in 1919.

Chromium orange has been in use since around 1809.

Viridian green paint contains chromium and has been in use since around 1838. Vincent Van Gogh was known to have used viridian green paint in his work, “Cafe Terrace at Night,” painted in 1888 and held by the Kroller-Muller museum.

Cobalt green paint is composed of zinc and cobalt and has been in use since the early 1800s.

Cerulean blue paint is cobalt based and began wide use in paints around 1860. Cobalt blue began use in paints in 1807. It is said that in December of 1882, Vincent Van Gogh wrote to his brother (Theo) that “cobalt blue is a divine color and there is nothing so fine as that for putting space around things” (cite: “Van Gogh’s Cobalt Blue,” Geldof and Steyn, Van Gogh’s Studio Practice, pg 256).

Fourier Transform Infrared Spectroscopy (FTIR) is used with the XRF to provide a complete compositional make-up of the art.  FTIR examines the organic composition and provides a transmittance or absorbance spectra of the paint, coating or other organic material.

Polymerization (Binding) is examined through the use of microscopy and the reaction to various forms of electromagnetic radiation.

All of these approaches are used to provide insight as to the age of the materials.  In addition, they develop information regarding whether the piece was falsely created using more recently available items or else through the manipulation of the appearance of age.

Forensic science and provenance together can help prove or disprove authenticity.

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