www.PaintingsAuthenticity.com    last Update: 15/04/2008

 


Fondazione Gottfried Matthaes
 

Determining the authenticity of
ancient paintings
 A section of the Museo d’Arte e Scienza



Information about the authenticity of modern paintings
on our web site www.dipintiautenticita.com

 

There are different approaches for determining The Authenticity of Ancient Paintings:
- verifying authenticity through a purely stylistic evaluation
- verifying the authenticity of a painting by means of objective tests of the ageing of the material
- verifying the authenticity of a painting with the use of scientific instrumental methods.
The combined results of the stylistic, material and scientific investigations will allow establishment of the compatibility of the painting with presumed elements or its inauthenticity.
 

 

A work of art
is material

prior still to being a message.

  Once finished, it acquires
an individuality of its own, which is a synthesis of the philosophy, sensibility and manual dexterity of its creator.

(M. Hours
former Inspector General 
of the Museums of France)

"Portrait of a Lady" by
Rogier van der Weyden

  

A recent copy of
"Portrait of a Lady"
(F. Pari)

 

 

 

Acknowledged value
of the museum’s scientific laboratory and its methods
for determining authenticity


 

Attitudes towards and use of scientific methods are influenced by local laws and customs.

Basis of judgment: the situation in Italy (where the museum is located)

The prime institution for the fight against forgery and imitations is the Guardia di Finanza or Financial Police. The most recent catalogue on the determination of authenticity in art, published by the same in June 2007, contains an exclusive six-page presentation of the scientific laboratory of the Museo d’Arte e Scienza in which its methods for dating paintings, furniture, and objects in ivory and other materials are illustrated in detail and their validity, in effect, endorsed.

 Judicial proceedings. The probatory value of the spectroscopic dating method is crucial to the outcome of civil and penal judgments involving the determination of the actual age of art works. A new Italian bill (26.10.2007) provides for fines and imprisonment for the forging of signatures and other characteristics.

The art market: the percentage of unauthentic art works currently on the market is very high. As a consequence a section of the trade rejects scientific methods out of economic necessity. Furthermore, when dating tests give negative results, dealers often tend to maintain that it is not the art work that is at fault but the scientific test result, or that the method is unknown.

 Art lovers and investors. Copies and fakes will continue to be offered as originals as long as buyers of art refuse to follow the same line of conduct adopted when acquiring other “products”, that is to say insisting on a dependable guarantee of the object’s authenticity as the condition for its purchase. It is senseless to content oneself with the personal opinions of experts alone in this age of technology and science. The art market will become trustworthy only when the art lover becomes a connoisseur and, as envisaged by the law, demands a valid certificate.
  

 

 

 

 

 

The value of expertise on art
in the scientific age

 


€ 4.500  
 Authentic

  


€ 5.000.000
 Auction of June 18, 2006


In the past, when called on to appraise and attribute a painting, art experts examined only the surface under natural light. A superficial examination of this kind was sufficient, however, because it was artistic style and technique they were looking at.

This way of examining a painting has remained the same to the present day, but the attention is now focused almost exclusively on the painter’s signature. The fact that today, as in the future, it is often impossible to attribute a work to an author with certainty, induces the thought that current art appraisal methods are all to the advantage of the market.

Whilst this type of ascertainment is to the dealers’ advantage, for buyers it could mean the almost total loss of their investment if one day this overemphasis on the signature were considered illogical and mistaken and a more traditional way of attributing art returned to favor.

Today it is already possible to reduce this risk thanks to the dating and scientific analyses of the various component materials of the painting and its support. Any incompatibility between the measured ages and information on the presumed author reveals to the owner, before he seeks an expert opinion, that he has acquired one of the myriad recent copies in circulation.


 Scientific methods used for determining the age of antique paintings are now applicable for works dating up to around 1920.

 

Get further and detailed information from our web site:
 www.SpectroscopyforArt.com

 

 


Analyses of paintings on a scientific base
 with methods and instruments of our laboratory

Portrait „Anna Selbtritt“, 1750

 

Legend for the painting

 

Instruments

Casella di testo: S Sg   S, Sg E   Sg O   O, Of   D, O     L, Lw, E, R, O       S, Sg R,O R,O     O, Of   O, S, Sg, D   E  
 
 and techniques

1)   Wood-panels
 ·     Ascertainment of the type and the precise age of wood
·     Additional test for excluding the use of old wood
S
Sg

2)   Loom of paintings on canvas
 ·     Ascertainment as for item 1
·     Comparison and evaluation of the holes into the canvas with the holes into the loom for the ascertainment of their contemporaneity

 S, Sg
E

3)   Examination of the pigments compatibility with the presumed age of the painting
 ·     Chemical analyses of the type of pigment
·     Optical analyses of the pigment
Sg
O

            Examination of the conditions of the layer of paint
4)   Evaluation of the craquelure: its thickness, depth and differentiation
      when added to the single pigments
5)   Examination of the crystallization and drying process of the paint layer


O, Of

D, O

      6)   General aspect of the surface: restorations, overpaintings, mechanical
            Damages and other conditions

 L, Lw, E, R, O
 

            Examinations of the preparation layer
      ·    Its chemical composition
7)   Research of preparation drawings by the artist
8)   Research of preparation drawings to produces a copy
S, Sg
R
R

9)   Irradiation of the layer of paint with monochromatic, infrared,
ultraviolet and Wood’s light

 O, Of
 
      10) Scientific and optical analyses of the author’s signature O, Sg, D, Lw

General examinations

 E

Legend for the letters

Abbrev. Type of analyses   Abbrev. Type of analyses
S IR Spectroscopy   D Duroflexometry
Sg IR Spectrography   Lm Monochromatic or UV-Light
O Optical methods (stereo-microscopy, digital processing of images)   Lw Wood’s Light
Of Micro or Macro-photography   E Examinations based on the expert’s skill and experience
R IR Reflexography      

 Each method and instrument is described and illustrated on the following pages.

 
Procedure of the analyses and prices
 

Once delivered to the laboratory the painting is submitted to preliminary analyses in order to avoid an unnecessary ascertainment in case of an unvalued copy or a fake. For this purpose the examinations 1, (2), 3, 5 and 9 are applied at the all-in price of EUR 250. The further procedure and the foreseen costs are agreed with the deliverer.

 
 


The scientific laboratory of the Museum

Every attempt to determine the authenticity of a painting must begin with tests and analyses to establish whether the age of the painting and the materials and techniques used are compatible with the presumed date of execution.
 

The objective elements attesting to the authenticity of a work are to be found in a scientific laboratory!
The Museum laboratory’s mission is to improve existing scientific methods and elaborate new methods for the ascertainment of the authenticity of art objects. The laboratory’s instruments and know-how for the determining of authenticity are at the disposal of collectors, art experts, restorers, art galleries and museums. (The staff of the laboratory, who speaks the main European languages, is at your disposal for any explanations).

 

Tests carried out by the laboratory:

Spectroscopic dating and characterization of wooden objects

Microscopic tests on paintings

Examination of underlying layers using infrared reflectography

Analyses of paint layers with a duroflexometer

Analyses with Wood’s light, UV and IR

 

 


FURTHER ANALYSES PERFORMED IN THE LABORATORY: Spectroscopic chemical analyses on pigments, glues, encrustations, patinas, products of corrosion. Scientific, practical and instrumental tests of authenticity on: ivory, amber, archaeological glass, pigments, metals, stones,  carpets, tapestry, prints, books, clocks and watches, china.

For further information see page 14

 

PRICES: the average cost of analyses is 75 Euro for each test; some tests are conclusive in telling fake and authentic items apart, such as wood dating and tests on the encrustations on pottery and bronzes.
For more information contact: Dr. Chem. Peter Matthaes (laboratory's director) Tel. 0039-02-72022488  -  Fax. 0039-02-72023156 -  Email: info@museoartescienza.com

 

 

ADDITIONALLY, in the Museum rooms there are 9 interactive test stations at the disposal of visitors for simple tests for ascertaining the authenticity of antiques.
 

test station room 8:
sniff test on excavated pottery

test station room 9:
test for revealing use of plastic

identification of glues and other synthetic materials with Wood’s light

test station room 9: examination with a magnifying glass of signs of wear and decorations on china

 

 

optical examination of signs of wear to identify an authentic piece of silverware

shadow reveals industrial or handcrafted manufacture of glass

the microscope distinguishes authentic patinas and encrustations from faked ones

the dull sound of a porcelain item reveals hidden restoration work

 

 


 

 

The necessity of dating a painting for its valuation
 

Icons are a telling example of how stylistic considerations alone are not sufficient to establish the date of a painting. Even though from an art historical standpoint there are clearly distinguishable painting styles, succeeding generations continued to reproduce the best-known and loved styles and themes. Only the dating of the wood, therefore, can permit certain and unequivocal classification.

 (Selection of icons from the
Museum’s collection)

  

 

   

age of wood: 310 years

  

age of wood:  240 years

 

 

age of wood:  200 years

  

age of wood:  160 years

  

age of wood: 100 years

 

 

age of wood:  85 years

  

age of wood:  35 years

  

recent fake

Similar considerations can be applied to paintings of a religious content.

 

 

 

 

The following pages propose
 three kinds of tests available
to the owners of paintings
to determine their authenticity on an
objective basis (excluding the artist's name!):

 

 

A) - Tests which the owner can carry out in his own home, following the instructions set out here or in the Museum's Handbook.

B) - Scientific tests carried out in the laboratory on samples taken by the owner and mailed to the Museum.

C) - Tests which can be performed only in the laboratory by bringing the object along. (See the first pages)

 

The examples shown here have been chosen by the laboratory of the Museum of Art and Science to advise or inform the owners of paintings of the numerous possibilities in existence, enabling them to better assess the value of their artefacts.

There are no descriptions of stylistic features, the formal aspects of which have already been treated by an abundance of art books in all languages. These books are, however, attentively read also by forgers who, wanting for instance to specialize in Gothic painting, can not only document themselves on techniques and styles of the period, but gain even more information than an artist or craftsman living at that time on the materials used and on the overall cultural context.
 

 

 

The texts and photos of this website are extracts from "The Art Collector's Handbook"
3 volumes in three languages, published by the "Museum of Art and Science"
www.ArtAndScienceHandbook.com

 

_____________________________

 

 

A)  TESTS WHICH CAN BE PERFORMED AT HOME

Visual tests with the aid of a magnifying glass (1:10). The three most significant examples have been chosen from among the numerous available.

1 - Craquelure


One of the most reliable clues to distinguishing old from new is offered by the network of cracks that develops over time in the paint layer (craquelure). This is caused almost exclusively by deformations in the painting's wooden or canvas support.

The canvas of a painting easily
 gets bent around the inner
border of its wooden stretcher,
causing the first cracks to develop
parallel to the stretcher (a).
Cracks that form also above the stretcher (b) 
have probably been created artificially.

 

In oil paintings cracks usually form
after 60 to 120 years.
They make their first appearance
in the whites.
This characteristic provides one of
 the few possibilities  of establishing
the authenticity of works created by the
great painters active around 1900,
such as Cézanne, Gauguin
 Van Gogh and others.

 

panel paintings
As the structure of the wood
 consists of long parallel fibres,
the swelling and shrinking of the support
as a result of humidity and heat
cause the surface to crack
 initially along the wood grain.

 

 

2 - Pigments


Most of the pigments used until the start of the 19th century were obtained from minerals, natural metal oxides, earths of various colours and a small number of vegetable colourants.

 

The size of the grains of pigments
is also of decisive importance for determining
whether they are "antique" or "recent".
Visible grains are proof that
the colours were ground by hand.

 

Since a colour's hiding power increases,
the smaller the size of the grains,
industrial pigments are ground
 as finely as possible.
Grains which are almost invisible in
a painting may be an indication that
 it is of recent production.

 

Many yellow pigments are
 unstable and sensitive to light.
Therefore, bright yellow in an
antique painting should draw
careful scrutiny. Yellow pigments
mixed with blue often serve to
 produce green. This is why green
hues are seldom vivid and tend
 to turn a nondescript
greenish brown.

 

 

 

3 - Patinas and protective varnishes

The outer layer of paint in
antique paintings undergoes
 severe chemical and physical
 change over the centuries.
For this reason antique paintings
were covered with a protective coat of
transparent varnish.
 In the absence of this varnish
the surface would look grey.
This grey veil, if present, is an
unfakable indication that the
 painting is antique.
It becomes visible if the protective
 varnish is removed with
cotton wool soaked in alcohol
(for test purposes clean only
a small area near the edge).

 

If the same test is carried out on
 a recent copy, fresh and industrial
colours re-emerge. The alcohol
test, preferably performed by a
restorer, causes no damage.

The most commonly-used method
for ageing a surface is to spray it with
a dark-coloured liquid.
 The uniformity of the marks thus obtained
differs from the myriad of tiny dark
lumps deposited over time.

 

 

 

B)  scientific examinations on samples of material taken by the owner and analysed by a laboratory.

   The purpose of analyses effected on samples taken from paintings is to investigate the following factors:
 

.

 Determination of the type of material and distinction between natural and synthetic.

.

 Comparison between the age of the material present in the painting and the date of introduction and utilization of the same in painting.

.

 Absolute dating of the wood used as support or stretcher.

Modern technology, applied by experts, allows the certain distinction between an antique painting and a relatively recent copy of the same,  but does not permit an original antique painting to be distinguished from a copy of the same age.
In order to know the name of the artist it is necessary to have the historical documentation of the painting appraised by a serious expert.
 

   Instructions on how to take samples of material

 

 

I


 

 

Panel paintings: gather a few mg of wood dust both from the surface and in depth from the rear of the panel, following the instructions provided in our website www.spectroscopyforart.com. The sample taken from the surface permits exclusion of the use of wood that was already old. The results of the analysis establish the age of the wood with certainty.
 Paintings mounted on wood stretchers: Carry out the above tests after ascertaining that the stretcher is original.

 II 

Pigments, binders in general and canvas: Remove a piece of canvas of the size of about 1 cm² bearing remains of paint (see drawing).
III

Specific pigments (whites, blues, yellows and greens):
Using a thin blade, remove about one mm² of the paint layer from an unimportant area of the painting.  

     The results of tests II and III give the verdict: “compatible” or “incompatible” with the presumed age

 

 


Short description of the natural and scientific foundations
of the spectroscopic dating of
wood
 

The essentials in brief

Infra-red spectroscopy is not a new method or a new discovery. New is only its application for the ascertainment of age and authenticity in art. It has been used for decades the world over by all chemical and pharmaceutical companies with thousands of instruments and with the same programme and equipment as the ones used by the laboratory of the Museo d’Arte e Scienza. Its extreme reliability, accuracy and facility of use have made the IR Spectroscopy in all fields where it can be applied, the number one scientific method.

Spectroscopic dating is based on two well-known factors:

·         All the natural materials on earth, including those used for creating art objects, are compounds of specific molecules.

·         Some particular molecules undergo changes with the passage of time.

The IR spectrum of wood shows its molecules or groups of molecules as peaks and valleys (Figures 1, 2). Signs of age caused by evaporation, oxidation and new combinations cause the lowering of some absorption peaks and, to a lesser extent, a shift in the same (Figure 3).
This dating method allows therefore two possibilities for the evaluation of the spectrum, each one already offering good results singly.

1 – The graphic evaluation of the curve (Spectrography)
 Right from the start of this research, the spectrographic measurement of the angle (α) formed between peaks of different heights permitted a dating accuracy of +/- 20% and these findings were communicated at the time, around 1995,  to a number of European museums and institutes.
 

 

  

Figure 2
 

Figure1

 

 


 

2 – The evaluation of frequency shifts      (Spectroscopy)

The discovery of shifts in absorption frequencies in spectroscopic analysis has boosted accuracy over the years to an unexpected extent and was inexplicably high in the first few years.

(Figure 3) - The diagram to the left is only one example of the many characteristics of a spectrum.



At present we are attempting to trace this accuracy, as well as the independence from climatic conditions, to biological programmes inside the cellular nucleus of the tree. The incredible precision of these types of biological programmes in general are well-known and understandable for the growth of wood. An answer to the question why the ageing of wood must also be programmed can be supplied only by the evolution of cellular research.


 The cell of trees, contrary to the cells of animals, is highly protected by a wall of cellulose, a hydrocarbon. Cellulose is extremely resistant to water and wood cells as well as datable wooden material are still existent in excavated Roman ships.
 
  Figure 4

Research in collaboration with a German
archaeological museum (1995).


               
Generation of reference tables to relate spectrum data to wood age:
 
The assignment of a spectrum to a specific wood species and to a specific age required the measurement of a great quantity of wooden objects of certain dating. This research, which called for many years of work on the part of qualified personnel was made possible only by the close and benevolent cooperation of international museums which began around 1993. The collaboration of some art museums terminated around 1995, since their curators feared there could be negative consequences for their collections. The Gottfried Matthaes Foundation, proprietor of the Museum, is, like the P. Getty Foundation, a non-profit organization at the service of art. Our cooperation with technical museums has continued.

 

The application of spectroscopic analysis for the dating of organic materials is patented
(It. Patent Nr. 01266808 - G. Matthaes, 1993)

 

C) specific tests carried out by the laboratory of the museum of art and science


Thanks to the laboratory's modern equipment, a painting can be subjected to analysis using infrared reflectography, Wood's light, a stereoscopic microscope, IR spectroscopy and other instrumental techniques.
 

Microscopic analysis
to examine the signs of ageing in the paint layer: the nature of the craquelure (natural or artificial - deep or superficial), the pigments (crystallinity,  purity and size), restoration and other factors.

 examination of craquelure

analysis of pigments

  


 

Wood's light and monochromatic lights permit an evaluation of the extent to which the painting has been restored, touched up and overpainted, as well as the identification of various fluorescent substances.

restoration work shown up        

stucco work identified

  


 

Infrared reflectography permits an in-depth examination of the painting bringing to light underdrawings or grids, pentimenti, and the depth of the craquelure, and identification of restoration work or the use of different materials.

depth of craquelure

 underlying grid

  

 


 

 

  

IR spectroscopic analysis permits the analysis of various materials to ascertain their compatibility with the presumed historic period: pigments, binders, glues and varnishes. Minimal sample quantities needed.

sample to be analysed enclosed in a KBr pellet

  

insertion of sample in the spectrophotometer

  


 

 

IR spectroscopic
dating of wood
for further information on
the dating of a painting's stretcher, support or frame
please visit our website www.spectroscopyforart.com

spectroscopic analysis unit

  

dating spectrum

  


 

 

Evaluation of the
 physical properties
 of the material
measurement of the dessication of the binder and the elasticity of the paint layer

analysis with duroflexometer

  

measurement of surface elasticity

  

The laboratory also digitalizes images obtained by the various techniques, carries out examinations under reflected and raking light, and performs microchemical analyses.
Certificates are issued with a clear and exhaustive report on the results of the analyses.
 

 

 

 

Graphic Art and Prints

Sheets of paper coloured by mechanized systems for mass production are hard to define as works of art. Furthermore, in the case of signed items sold at relatively high prices, the risk that they are not authentic is also very high.
 

Let us take for example the most widely sold and esteemed graphic artist: Salvador Dalì.
It is estimated that of the Dalì prints available today on the market, hundreds of thousands of all of them, are fakes. And the chief faker was Dalì himself. The facts are well known.
There is no typical signature of Dalì in the field of his graphic work. Only the fraudulent signatures are consistently repeated.

The attempt to ascertain the authenticity of a print is fruitless.

 

Dalì

 

  

Icons

Icons were painted in cloisters by nuns and monks as a testimony to their faith and devotion. The icon painter tries to impart a transcendent spirit to the painting by praying at length and fasting as he creates the image. To reach this objective the faces are painted in different layers of colour, each coat of which is left to dry before the next is added, thus leaving the artist-monk long intervals to spend in prayer.

The main clue to distinguishing authentic icons from faked ones at first sight is the stratification of the paint on the faces, which appear almost in relief if observed under a raking light (see Collector's Handbook pp. 65-76)

For all other investigations, what has been said for panel paintings holds good also for icons.

 


 

The Founders and the permanent staff
of the Museo d’Arte e Scienza

   
 
   
 

Gottfried Matthaes
 Founder and  President

Giovanna Cozzi Matthaes
 Co-founder

  
 
     

Dott. Chim. Peter Matthaes
 Lab. Director and CTU

 Patrizia Matthaes
 Administration		 Silvia Mayer
 Language and Communication		 Dott. Avv. Martin Matthaes
Lawyer - International Law
 
 
Chiara Civardi
First lab assistant		 Roberta Delmoro
 Art Historian (Freelance)		 Marta Cugnasca
 Data processing		 Sonia  Checchini
Conservation
       

 

 

 

NOW OPERATIVE !

Branch of the Milan scientific laboratory for determining the authenticity
of valuable antique art objects


The announced laboratory in Germany to serve central Europe is
now operative for the taking of samples from wooden objects to be dated and for the issuing of certificates.
 
 Please contact Dr. Martin Matthaes
 +49 (0) 17676305108 – mm@museoartescienza.com

The house, which has belonged to the Matthaes Foundation (Museo d’Arte e Scienza) for 45 years, is situated on the shores of Lake Constance, near Lindau.
 

Other requests may be sent, as always, directly to the Milan laboratory at the following address:

Museo d’Arte e Scienza
Via Q. Sella 4 – 20121 Milano
Tel. 0039 02 72022488
Fax 0039 02 72023156
e-mail: info@museoartescienza.com

  

 

 

 

With this guide to detecting fakes, you will always have a trusted expert by your side, ready to provide you with clear and straightforward answers as to the authenticity and originality of the items that arouse your interest.
 
Title: THE ART COLLECTOR'S ILLUSTRATED HANDBOOK (three volumes - three languages)

The Author, Gottfried Matthaes, a physicist, was born in Germany of a family of longstanding artistic tradition and since 1960 has dedicated himself to the study of practical and scientific methods for the ascertainment of authenticity. In 1990 he founded the "Museo d'Arte e Scienza", the only one of its kind in the world, in the centre of Milan where most of the objects illustrated in the handbooks are exhibited, together with its attached laboratory. In 1993 he discovered and patented the application of IR spectroscopy for the age dating of wooden art objects.
Contents:
VOLUME 1: Ivory, Paintings, Icons, Carpets and Rugs, Tapestry, Furniture, Glass, Ceramics, Scientific Methods
VOLUME 2: Paper, Books, Prints, Metals, Clocks, Walking Sticks, Pipes, Musical Instruments, Precious Stones, Amber, Pearls, Enamel Paint, Dolls, Toys, Fans
VOLUME 3: Minor Asian Arts, Excavated objects, Buddhist Art, African Art, Indonesian Art
Price: Volume 1 (278 pages) 40.00 Euro
Volume 2 (128 pages) 30.00 Euro
Volume 3 (128 pages) 30.00 Euro
Shipping charges are not included .		 International Code: Volume 1 - 2000, ISBN 88-900454-5-0
Volume 2 - 2001, ISBN 88-900454-6-9
Volume 3 - 2002, ISBN 88-900454-7-7
How to buy it:
  • in all bookshops giving the above mentioned ISBN code number
  • directly at the Art and Science Museum (with discount)
  • by e-mail

 

 


Examples of pages taken from volume 1
 

 

  

 Vol. I

      Subject:  PAINTINGS and ICONS   Total pages on subject: 92  Illustrations: 207

      Pages 18 and 22, Chapter  Craquelure - 26, Chapter Fake craquelures

    Page 48, Chapter Copies: kind and value

Sample pages

 

 

     

 vol. I

      Subject: PAINTINGS and ICONS   Total pages on subject: 92  Illustrations: 207

       Page 67,  Chapter Faces        Page 70, Chapter Icon oklads

       Page 84,   Chapter Reflectography          Page 86, Chapter Infrared rays

Sample Pages