The National Gallery’s Scientific Department  was founded in 1934 and has become a world leader in the study ofmaterials and techniques in Western European paintings. 

Today, it works ever more closely with curators and conservators to investigate physical characteristics of works in the collection and protect paintings for the future.  Above: Background to Ashok Roy, the EPSRC-funded gas-chromatography-mass- spectrometer

Gas-chromatography linked to mass-spectrometry is the core technique for microanalyses of paint samples, and the techniques of analysis were developed first in the National Gallery laboratory, which remains a world leader in the study of the materials and techniques of Old Master paintings.

Paint binding media includes drying oils used in paintings, such as linseed oil, walnut oil and poppy seed oil. Analysis shows, for example, whether the oil was pre-treated by 'heat-bodying' (or thickening) before use by the painter. Added resins and other materials can also be identified and the state of degradation of the binder can be assessed. Paintings in other media, such as egg tempera can be identified, as well as complex combinations of media.

Modern scientific methods, including infrared imaging, X-ray images, electron microscopy and mass spectrometry can provide fascinating insights into the materials used by artists, studio practice and the ways paintings can change over time.
Close Examination  explores this pioneering work by presenting the varied and fascinating stories behind more than 40 paintings in the National Gallery’s collection.

Held over 6 rooms, it represents major challenges faced by Gallery experts, featuring work by Raphael, Dürer, Gossaert, Rembrandt and others.

Deception and deceit

Mistakes

Transformations and Modifications

Secrets and conundrums;

Redemption and Recovery

And a special Botticelli focus room.

Room 1: Deception and Deceit
Some paintings in the collection raise complex questions of disputed authorship and authenticity. These range from straightforward period copies to modern forgeries created with the intent to deceive. The lengths forgers will go to deceive is shown in the Portrait Group.

This has been identified as the work of an unknown forger of the early 20th century, imitating the style of Renaissance profile portraits. The National Gallery purchased the painting in 1923, believing it to be an authentic 15th century work.

Scientific analysis exposed the deception, revealing the artist had used pigments unavailable before the 19th century. It also emerged that the top layer had been coated with shellac, a natural resin, to simulate the appearance of age.

Room 2: Transformations and Modifications
The Gallery owns several paintings which, over the course of time, have been modified to satisfy changing tastes or interpretations. A provocative Renaissance depiction of a Woman at a Window, probably 1510–30, was dramatically altered in the 19th century to satisfy restrained Victorian tastes. The girl’s hair changed from blonde to brunette, her expression made more innocent and her bodice  less revealing.

In the 1700s, a painting by an unknown German artist, Portrait of Alexander Mornauer, about 1464–88, was altered to resemble a work by the more famous (and highly collectable) artist Hans Holbein.

Microscopic examination of paint sample cross-sections revealed that a layer of blue paint had been applied over the original brown background. The style of the sitter’s hat was also altered.

The changes convinced an 18th-century aristocrat that he was buying an authentic Holbein. The Gallery acquired the painting in 1990 and conservators were able to safely remove these additions to return the painting to its original state.

Room 3: Mistakes
This room focuses on the misattribution of paintings, and examines how scientific analysis and connoisseurship can work together to correct past mistakes. A Man with a Skull was acquired by the Gallery in 1845 as a work by Holbein.

Even at the time many experts doubted the attribution. Modern dendrochronological analysis to determine the age of the wood panel support has since shown the painting post-dates Holbein’s death in 1543. The exhibition will reveal a new attribution for this painting.

Room 4: Secrets and Conundrums
Despite triumph and advance, some paintings remain stubbornly mysterious. For example, it is difficult to exactly recreate the workings of an artist’s studio: the materials and techniques used, or the role of assistants.

Close Examination highlights some of the important discoveries made in this area; for instance during recent conservation work on The Virgin and Child with Two Angels, about 1475, experts were able to take a closer look and solve a long-standing conundrum over authorship.

Originally acquired as a work by Domenico Ghirlandaio, the painting was later demoted, attributed to the workshop of Andrea del Verrocchio. However, after removing layers of old retouching work, examining the underdrawing with infrared reflectography, it became clear that Verrocchio himself painted the Virgin, the angel on the left and the landscape in the background. His assistant, Lorenzo di Credi painted the angel on the right and the infant Christ.

Verrocchio was one of the finest sculptors of the Renaissance and tutor to both Leonardo da Vinci and Sandro Botticelli, but very few paintings by him have been identified with any certainty. This discovery has made it possible to reassess other works by the artist as well as his legacy as a Renaissance painter.

Other conundrums featured in the exhibition remain tantalizingly unsolved. A Dead Soldier, an atmospheric painting of the 17th century, was attributed to the Spanish master, Diego Velázquez. The theory has now been discounted, but while the painting is thought to have originated in Italy, precise identity of the artist remains a mystery.

Room 5: Being Botticelli
At various points in the National Gallery’s history, some works were enthusiastically acquired on mistaken attributions to iconic artists. In June 1874 the Gallery purchased two
 Botticellis – or so it seemed. One of these (Sandro Botticelli, Venus and Mars, about 1485) is now one of the most beloved paintings in the collection.

The other painting (Follower of Sandro Botticelli, An Allegory, about 1940 –1550) was then thought to be the companion to Venus and Mars. Some even thought it the more desirable of the two.

However, this painting was discovered to be a pastiche, painted by a follower in the style of the great master. The paintings will be shown side-by-side so that visitors can test their own skills of connoisseurship.

Room 6: Redemption and Recovery
The final room of the exhibition celebrates instances in which the work of great painters has been re-discovered through a combination of scientific analysis, conservation, connoisseurship and art historical research.

Until 1991, the whereabouts of Raphael’s original painting of The Madonna of the Pinks, about 1506–7, was an intriguing mystery for art historians. Only copies of the painting were known. However, during a visit to Alnwick Castle in Northumberland, Dr Nicholas Penny spotted an intriguing painting which demanded closer examination.

Infrared reflectograms revealed an exquisite underdrawing beneath the paint surface, bearing all the hallmarks of Raphael’s hand.

Subtle differences between this underdrawing and the finished painting, particularly in the costume and background landscape, showed the artist had changed his mind as he worked.

No copyist wishing to pass a painting off as the original would have departed from his model in such a way. Chemical analysis confirmed that the pigments used were typical of Raphael’s distinctive palette, including some that ceased to be used after the 16th century.

'Close Examination' is the first major exhibition to explore the full range of scientific discoveries made by a leading art gallery within its collection. The close working relationship between scientists, conservators and curators constantly yields new and exciting findings while helping us to gain a deeper understanding of important works of art.