September 5, 2021

The Hitler Forgery Industry

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2017  |

Dating watercolours - pigment research

In 2017 Droog Magazine investigated the claim by NIOD, the Netherlands Institute for War, Holocaust and Genocide Studies, of having acquired an “almost certainly authentic” Hitler watercolour.

Part of our investigation was consulting the right experts, something NIOD had failed to do. We approached two experts on pigment research: dr. Luc Megens and Liza Leslie.

Luc Megens was, among other things, involved in the research of works by Vincent van Gogh. He works for the Netherlands Cultural Heritage Agency and is affiliated with the University of Amsterdam.

See: www.researchgate.net/profile/Luc_Megens

Liza Leslie, accredited member of APROA-BRK, the Professional Association of Curators-Restorers of Works of Art. She is employed by the internationally operating restoration and conservation company Sofrino (Maastricht/ Brussels/Moscow). See: www.sofrino.nl/over-ons/

Droog Magazine: [1] Can pigment research tell us from which year (or approximately which years) a watercolour originates? Or does it only tell us the year a watercolour was made?

Liza Leslie: "It is impossible to determine a precise year on the basis of pigment research. It is, however, sometimes possible to say with certainty that a certain work was made after date X, as the pigment composition was not available on the market earlier. This is much more difficult for the 20th century, as most current pigments were introduced to the market at the end of the 19th century.”

Luc Megens: "Since prehistoric times, humans have used pigments to colour and paint objects. Initially, these were mainly earth pigments (ochres), soot, and possibly blood. In ancient Egypt, the first (inorganic) synthetic pigment, the so-called Egyptian blue, was made. In Roman times, white lead was also already known, which was made by reacting lead with vinegar. Vegetable extracts were also used as dyes or pigments.

From the early modern period, more pigments were added, and after the mid-19th century there was an enormous boom in the development of synthetic organic dyes and pigments. Virtually all of these pigments have subsequently been in use or have remained known.

Therefore, the occurrence of a pigment in a painting can usually only provide a terminus post quem, i.e., the painting may have been made after the pigment was discovered. Many organic synthetic pigments may have ceased production at some point, but that does not necessarily mean that they could not have been used afterwards. Good forgers will also use mediums (paper, canvas, wooden panel) and dyes from the period of the work to be forged.”

[2] Can research - by any means - determine whether a signature was applied to a watercolour shortly after the completion of  it?

Liza Leslie: "This can be determined with macro photography. This way you can compare the structure of the signature with the paint structure of the background. In principle, this should be 'wet on wet', with exceptions. However, this is more difficult with watercolours, as these are more often signed in pencil. If this is the case, this analysis will not work."

Luc Megens: "We are engaged in the scientific study of painted objects, particularly the pigments on them. Based on that, it is virtually impossible to say whether a signature on a watercolour was applied simultaneously or later. On (oil) paintings this is sometimes clear, as it can be seen that a signature has been applied to a varnish between the painting and the signature. I doubt whether a restorer can tell the difference between a hundred or fifty years old signature from a technical point of view.”

[3] Is it necessary to have 100% reliable comparison material for such pigment research? The problem with works attributed to Hitler is that almost nobody knows which are the real ones and which are the fakes, with the complicating factor that there are more fakes than real ones.

Luc Megens: "We have mapped the use of pigments in the majority of Van Gogh's oil paintings. Patterns can be discerned from this. Van Gogh used a different palette of pigments in his French period than in his Dutch period, and there are also some differences between Paris and the south of France. But even then, a number of authentic, and art-historically certainly period-dated works are not included.

So having 100% reliable comparison material does help, but it still does not provide certainty. The artist may well have used different paints for a particular work than he usually did. A small number of objects for comparison gives only a false sense of security.

Liza Leslie: "Signatures are usually identified by comparison with forty or fifty other signatures available from the same hand, using macro photography. This is not a problem in the case of Adolf Hitler."

It is a problem, though. There are only a very limited number of thought to be authentic Hitler watercolours possibly available for research; some in Washington, some in Florence. Printed reproductions exist of a further limited number - we do not know whether they are suitable for proper signature analysis. But this aside.

[4] Does pigment research really require 'invasive research'?

Luc Megens: "I do the pigment research on watercolours non-invasively, using the so-called X-ray fluorescence technique (XRF), which detects the chemical elements in the paint. However, this only works for inorganic (and a few organic) pigments. In order to subsequently determine exactly in which chemical compounds these elements occur, X-ray diffraction is also used, which can be done non-invasively for objects up to a few decimetres in size. For the organic pigments, non-invasive techniques are available, but they are less specific than sample research. For sample research we have a method that allows a macroscopically invisible sample to be taken from the watercolour."

Liza Leslie: "Standard pigment analysis requires taking a cross section of an area of the artwork where the pigment can be found using SEM-EDX.

However, there are alternatives. The best way to distinguish contemporary (synthetic) pigments is by using Micro-Ramanspectroscopy (MRS) that compares the wavelengths of reflected light to a database."

[5] Are there any techniques to determine the year a watercolour and its signature were applied to a paper?

Liza Leslie: "Apart from pigment analysis, it might in principle be possible to determine a time period on the basis of style analysis (drawing and signing), paper analysis and binder analysis."

Luc Megens: "The only dating technique I know of with a (theoretical) resolution of 1 year is dendrochronology, where growth rings in wood are compared to a reference chronology. So this is not applicable."

[6] Does pigment research always require comparison material from another work made by the same alleged maker?

Liza Leslie: "Not necessarily, but it would help."

[6b] Approximately how much does pigment research cost, both in terms of time and money?

Luc Megens: "Thorough pigment research of a watercolour will cost several weeks and thus several thousand euros."

Liza Leslie: "It can be done within a few days. It's best to start by determining the white pigments present. MRS can distinguish between different types of titanium. This in combination with UV/IR analysis for other (organic) pigments and analyse any signing will cost around 800-1000 Euro."

© Translation Bart FM Droog, 2021.
Original text: Experts over pigmentonderzoek. Dr. Luc Megens en Liza Lesie. Interview conducted by Jaap van den Born & Bart FM Droog. Droog Magazine, Eenrum, 16-12-2017.
http://www.bartfmdroog.com/droog/niod/experts.html

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