Cleaning Modern Oil Paints Project

Tate is the newest recipient of the NHSF Gold Open Access grant for the publication of heritage science research. The grant enabled the publication of the research paper Scientific investigation into the water sensitivity of twentieth century oil paints’, available for free in Microchemical Journal. In this guest post, the paper’s authors tell us more about the Cleaning Modern Oil Paints project.

The Cleaning Modern Oil Paints project (CMOP) is a collaborative European research project, funded through the JPI Heritage Plus programme, which runs from June 2015 – May 2018. The project aims to investigate conservation challenges associated with twentieth and twenty-first century oil paintings in order to ensure that modern oil paintings continue to be fit for display for future generations.

Many unvarnished twentieth and twenty-first century oil paintings are exhibiting unusual water sensitivity. Water sensitivity can be defined as the unwanted removal of pigment and/or original material when a discrete cleaning test is carried out using a dampened cotton swab on the surface of a painting. Water sensitivity is not restricted to a particular oil-paint brand, or artist, and affects a broad range of paintings.

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Winsor & Newton Artist Oil Colour swatches that were studied as part of the microchemical journal paper. Copyright Tate.

Water sensitivity is problematic for conservators, since many of the well-established methods for removing surface dirt (which naturally gathers over time) involves the skilled application of water based cleaning systems.  Since dry-cleaning methods, for example using dry brushes or specialist sponges, are not always particularly effective at removing soiling, water sensitivity can complicate or even prevent effective treatment. This is problematic as accumulated surface dirt can change the appearance of paintings e.g. through altering the saturation, intensity and gloss of paint passages, and can, over the longer term, contribute to other unwanted side-effects relating to ageing and deterioration.

The interdisciplinary CMOP team have been investigating the underlying causes of water sensitivity in modern oil paints. This information has been used to inform the systematic testing and evaluation of selected cleaning systems for use on water sensitive modern oil paintings, with the aim of informing conservators about the risks involved and how to minimise them.

Part of the CMOP research has involved the chemical analysis of a series of naturally aged modern oil paint micro-samples, taken from case study oil paintings and from historic Winsor & Newton (W&N) artists’ oil paint swatches.  The W&N paint swatches were originally produced by the manufacturer for quality control testing, and were subsequently donated to Tate by ColArt UK for research purposes.

W&W Artist Oil Colour swatches studied for the paper, shown in tungsten light (left) and UV light (right). Copyright Tate.

We are pleased to announce that the National Heritage Science Forum has kindly sponsored the Gold Open Access publication of a key CMOP research paper, entitled Scientific investigation into the water sensitivity of twentieth century oil paints, now published in the peer-reviewed Microchemical Journal. This describes an in-depth investigation into the chemical characteristics of water sensitive paint passages, and likely causal factors.

The research at Tate is led by Principal Conservation Scientist Dr Bronwyn Ormsby, with Post-doctoral Researcher Judith Lee, and with the support of Tate’s Collection Care Research. More information on the project and details of the key CMOP project dissemination event; Conference on Modern Oil Paints taking place on 23-25 May 2018, are available on Tate’s website.

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Detail of a case study oil painting analysed as part of the project. Copyright Tate.

 

The paper Scientific investigation into the water sensitivity of twentieth century oil paints is co-authored by Judith Lee and Bronwyn Ormsby of the Tate Conservation Department, Ilaria Bonaduce, Francesca Modugno, Jacopo La Nasa and Klaas Jan van den Berg.

The National Heritage Science Forum provides Gold Open Access grants to help to open up access to heritage science research. This funding is available to employees, students and members of our member organisations – find out more.

Polychromy Revealed: from medieval wood craftsmanship to 3D printing (Paola Ricciardi)

The next post in our British Science Week 2018 series is by guest writer Paola Ricciardi. Paola Ricciardi is the Research Scientist at the Fitzwilliam Museum in Cambridge. She specialises in the non-invasive analysis of polychromy (multi-coloured painting) in cultural heritage objects. In this blog, Paola talks about a workshop on digital imaging, modelling, making and interpretation of 3D cultural heritage objects and their replicas.

The Fitzwilliam Museum holds a small but exceptional collection of medieval wood sculptures, largely polychrome, made across Western Europe c.1300-1550. For the most part extremely fragile, most of the sculptures have never been exhibited and are largely unknown to the public and to academics. Following a 10-month pilot project in 2017, we are currently running a series of activities funded by the Arts and Humanities Impact Fund of the University of Cambridge. These activities are aimed at maximising the impact of the pilot and at defining routes to impact for a large-scale research project – POLYCHROMY REVEALED – which will enable us to investigate, interpret, conserve and display the collection, ultimately transforming it into a resource that can be utilised for teaching, research and public engagement.

Picture of pair of kneeling angels. Copyright Fitzwilliam Museum, Cambridge
Pair of Kneeling Angels, Northern Italy?, 15th Century. Image copyright – The Fitzwilliam Museum, Cambridge.

Three events, running in March-May 2018, are particularly aimed at opening a dialogue with scholars, NGOs, industrial partners and crafts/technology practitioners interested in three-dimensional digital modelling; making; interpretation of; and interaction with, cultural heritage objects and their replicas. We want to assess the state-of-the-art of research in these fields and to establish guidelines for the choice of suitable and affordable solutions, which can then be shared with other museums and cultural institutions. Museum audiences are also involved and will be asked to respond to/interact with the outcomes of the initial phase of activities, in order to inform our methodology and choices for the large-scale project.

The real potential of ever-improving 3D visualisation and ‘making’ technologies is still to be fully explored and as such it is the focus of much attention, as demonstrated for example by a well-attended two-day conference recently held at the British Museum and by the ReACH project, led by the V&A Museum. On 15 March, we ran a half-day workshop in collaboration with the University’s Digital Humanities Network. The workshop brought together experts in a range of topics related to the study of, and interaction with, three-dimensional museum objects, such as 3D sensing, digital modelling, digital and physical making, as well as interpretation and outreach. Speakers and participants discussed the various ways in which digital 3D methods can support and enhance our study and the public’s perception of three-dimensional objects.

Image of panel of speakers. Copyright The Fitzwilliam Museum
Panel speakers. From left to right: Steven Dey, Anais Aguerre, Jonathan Beck and Panel Chair, David Saunders. Image copyright – The Fitzwilliam Museum, Cambridge

Workshop participants were given a demonstration of a structured light scanner which was used to produce models of a selection of polychrome wooden sculptures in the Fitzwilliam Museum collection. They were then asked to work in groups and issue a ‘creative challenge’ to design and produce objects inspired by the original medieval sculptures, based on the 3D models.

Image of Jonathan Beck using a structure light scanner to produce a 3D model of a medieval sculpture. Copyright The Fitzwilliam Museum, Cambridge.
Jonathan Beck using a structured light scanner to produce a 3D model of a medieval sculpture. Image copyright The Fitzwilliam Museum, Cambridge.

The challenge will soon be advertised to members of Cambridge’s Community Workshop MakeSpace and more broadly, and will result in their creations being displayed during a late-night opening of the Fitzwilliam Museum in May. We hope people will feel inspired by the creative challenge and we are very curious to see what they will create!

Image of working together to issue a creative challenge. Copyright The Fitzwilliam Museum, Cambridge
Working together to issue a creative challenge. Image copyright The Fitzwilliam Museum, Cambridge

Find out more about the Polychromy Revealed project

The Fitzwilliam Museum houses the principal collections of art and antiquities of the University of Cambridge, and holds over half a million objects in its care. It leads the University of Cambridge Museums (UCM), a consortium of the eight University Museums and the Cambridge University Botanic Garden, which works in partnership with other Cambridge University collections as well as with museums regionally, nationally and internationally. The University’s collections are a world-class resource for researchers, students and members of the public representing the country’s highest concentration of internationally important collections, all within walking distance of the City Centre. Arts Council England has awarded UCM National Portfolio Organisation status from 2018-2022.

Advanced imaging technologies uncover hidden details on Rubens paintings

Next in our British Science Week 2018 series, Historic Royal Palaces’ Senior Conservation Scientist Dr Constantina Vlachou-Mogire tells us about investigating the Rubens ceiling paintings at Banqueting House…

Historic Royal Palaces is preparing for the 400th anniversary of the Banqueting House, which will take place in 2022. During this major project we have a rare opportunity to access and study in detail the Rubens ceiling paintings, their fabrication technique and current condition.

The Banqueting House is the last surviving building of Whitehall Palace which was destroyed by fire in 1698 (Figure 1). Set within a decorative coffered ceiling designed by the building’s architect, Inigo Jones are nine paintings by Rubens, the artist’s largest and most accomplished works to remain in the context for which they were designed. The paintings were commissioned in about 1629 by Charles I as a testament to the glory of the Stuart monarchy through the depiction of his father James I’s life and achievements.

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The Main Hall at Banqueting House

These internationally significant paintings are an integral component of the architecture of the hall. Originally the Banqueting House Rubens ceiling paintings were oil-on-canvas stretched on strainers, but since 1907, they were attached to plywood boards. During their long history the paintings have been restored nine times—including in 1940 when they were cut up to evacuate the gigantic panels from the building.

High-resolution multi-spectral imaging

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Figure 2: Details of the multispectral gigapixel images of The Apotheosis of King James I panel (a. visible light, b. infrared reflected, c. ultraviolet-induced luminescence)

The first phase of our project involved capturing the condition of the paintings in high resolution images (Figure 2). The scale of the paintings, covering a total surface of 243 m2, and their position 17 m from the ground, made this task particularly challenging; however, recent advancements in digital photography helped us to overcome these difficulties.  Collaboration with imaging specialists developed the application of GigaPan technology to document all nine paintings from the ground in visible light and infrared light as panoramic ‘Gigapixel’ images. Ultraviolet-induced luminescence images were taken at close-range from a scaffold, by illuminating small sections of the painting and later stitching the images together to full-painting size. Superimposing the visible, infrared and ultraviolet images allows analysis and detailed classification of the current condition of the paintings as a standing record. This will underpin further investigations and inform the programme of conservation of these important paintings.

We would like to thank the following external collaborators for their expert insights and contributions to the successful progress of this cross disciplinary project: UV/IR imaging Dr Giovanni Verri (Courtauld Institute of Art) and Steven Paine (Paine & Stewart), 3D laser scanning, visible ‘Giga’ imaging John Hallett Jones (Glanville Consultants).

Assessing the light fastness of 16th century Indian paintings (Michela Rampa)

Next in our British Science Week 2018 series, Michela Rampa talks about her student placement at The British Museum, analysing colours in 16th century Indian paintings and assessing light sensitivity. Find out more at The British Museum’s British Science Week event on Saturday 17 March.

Hello, my name is Michela Rampa. I am a student from the University of Rome, La Sapienza, in Italy where I am studying to become a museum scientist. I am currently doing a student placement at The British Museum for my final dissertation. What a fantastic opportunity!

At The British Museum I am based in the Scientific Research Department but also regularly meet with conservators. I am learning how to assess whether museum objects might fade when exposed to light using “microfadeometry”. Microfadeometry is a technique that involves exposing a very small area on an object to an intense light for a short amount of time and recording the colour change on this small area. By comparing the colour change with references, it is possible estimate whether the object is sensitive to light or not.

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Examination of a 16th century Indian painting

Why is it so important to assess the lightfastness of museum objects? Many museum objects are light sensitive, for instance: watercolours, prints or textiles. We cannot stop fading from occurring when these objects are displayed, but we can ensure that light-sensitive objects fade so slowly that they will be seen by countless generations of visitors to the Museum in the future. Knowing if an object is likely to fade when exposed to light helps curators to decide how long  it can be displayed and under which conditions. For example, microfading tests carried out on Hokusai’s iconic prints ‘The Great Wave’ and ‘Red Fuji’ last year showed that these should be displayed using dim light for a short amount of time (read about it here).

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Experimental Technical Imaging laboratory in The British Museum

I am currently investigating the lightfastness of some Indian paintings, which will go on display in the new Albukhary Foundation Galleries of the Islamic World at the end of this year. One of them is a very colourful Hamzanama painting made in 1500. (Hamzanama is a series of manuscripts, most of them illustrated, that narrate the legendary deeds of Amir Hamza, the uncle of prophet Muhammad). It is very valuable and I have identified at least 13 different colours on it! I expected that most colours on this painting were produced using mineral pigments and therefore would not fade. However, I am discovering that, on the contrary, several colours, such as green, are light sensitive! I am hoping to perform more analysis to find out why these colours are affected by light. Work in progress!

In the meantime, if you want to know more about the work scientists do at the British Museum, please come and find me and the rest of the Scientific Research team at our annual event ZOOM IN: a closer look at science on Saturday 17 March 2018, 10.00 – 16.00, in the Great Court at The British Museum. Learn about all of the different techniques that are used to analyse the Museum’s collections, handle different kinds of raw materials and see the latest behind-the-scenes technology in action. This is a FREE event too!

Michela can be contacted by email and on LinkedIn. You can find out more about the upcoming Albukhary Foundation Galleries of the Islamic World on The British Museum website.

Five minutes with…Dr Bronwyn Ormsby, Senior Conservation Scientist, Tate

What’s your background in heritage science?

I loved art, art history and chemistry at school and did not know how to combine them into one career. I originally studied biochemistry at Sydney University (Australia) and stumbled into the conservation profession, volunteered for a while, worked as an assistant conservator, trained as a painting conservator at the University of Canberra (Australia) and worked for a number of years at the National Gallery of Australia (Canberra, Australia). It was during my time there I realised I was interested in exploring scientific questions around paint and conservation processes and made the decision to pursue a heritage science career. Moving back to science involved completing a 2-year post-graduate heritage science internship at the Hamilton Kerr Institute (Cambridge, UK) a doctorate at Northumbria University (Newcastle, UK, 1999-2002) which was primarily a chromatographic study of paintings by William Blake. Since 2003 I have been working at Tate, initially as a post-doctoral fellow (2003-2007), and now as one of two staff Conservation Scientists (2007- ).

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Tate Britain. Most of the conservation sections, including conservation science, are located at Tate Britain.

 

What’s your role at Tate?

The Tate Conservation Science department has two full-time scientists and one part-time preventive conservator. We work together to contribute to scholarship and collections care, and have specific scientific skills and areas of research, with some overlap and collaboration. I am responsible for the chemical analysis of samples removed from works of art with FTIR and GCMS, I also advise conservators about analysis and research, and translate scientific information. I lead research into the materials and conservation of modern and contemporary art which includes supervising post-doctoral, doctoral and pre-doctoral fellows/students/interns, publishing, giving workshops and presentations.

One area of ongoing research is to understand the constituents and properties of paints used by artists in the 20th and 21st centuries and to develop appropriate conservation treatments and preventive conservation strategies. As we are a small department we frequently collaborate with internal and external partners: sometimes we consult experts in particular materials or particular analytical/imaging techniques and our research projects are frequently highly collaborative.

Dr Bronwyn Ormsby at work
Dr Bronwyn Ormsby, loading up samples of paint into the PyGCMS autosampler for polymer analysis.© Tate

 

What’s been the most exciting or challenging thing you’ve worked on recently?

Two recent projects have both involved collaboration with The Dow Chemical Company (DOW), based in the US. One project focussed on developing cleaning systems for use on unvarnished modern and contemporary painted surfaces with Dow and the Getty Conservation Institute; this has now developed into continuous professional workshops for conservators (Cleaning Acrylic Painted Surfaces). The other project focussed on the Mark Rothko’s painting Untitled, Black on Maroon (T01170, 1958), which was vandalised at Tate Modern in 2012. For this, Dow scientists helped us out by exploring solvents for the safe removal the graffiti ink from the painting – I am very proud that the Project team and collaborators successfully enabled the redisplay of this painting in 2014.

Ink sampling Rothko vanadsiation
Dr Bronwyn Ormsby sampling the ink from Mark Rothko’s Untitled, Black on Maroon (T01170, 1958), soon after it was vandalised in 2012. © Tate

 

Who inspires you?

I am frequently inspired by my colleagues at Tate and around the world, as this is a profession that requires an authentic passion for art and lasting commitment. Many of us work in small teams or solo, and have to keep raising our own profiles as well as striving to stay relevant. I am also inspired by artists like Mark Rothko, who used paint materials to create works of art that encourage the kinds of visceral experiences normally reserved for places of worship. Having had the privilege to work very closely with one of his Seagram Mural paintings, I feel even more in awe of his achievements.

What do you love most about your job?

I love being so close to art on a daily basis and problem solving with such an extraordinary range of materials, works of art and issues.

In a single sentence, tell us what’s great about heritage science?

Heritage Science helps people to understand and value cultural heritage in the here and now, while also enhancing the chances of its survival into the future.