What can be gained by technical analysis? The example of the Luttrell portrait attributed to Hans Eworth
Aviva Burnstock, Head of Conservation, The Courtauld Institute, University of London
Making Art in Tudor Britain
Abstracts from Academic Workshops (2007-8)
Funded by the Arts and Humanities Research Council
The talk provided an introduction to the methods for technical examination of Tudor portraits with a focus on critical evaluation of the technical data. Aspects of a technical study of the Courtauld Institute Gallery's Portrait of Sir John Luttrell attributed to Hans Eworth carried out concurrently with conservation of the painting in 1998 provided an example for highlighting more general points about the gathering and interpretation of technical material.
The importance of interpretation of all aspects of technical data is exemplified by the deductions that can be made from examination of the surface assisted by a middle range magnification optical microscope, where the experience of the conservator and advances in technology combine to provide information about the physical aspects of picture making. The identification of red chalk used for underdrawing in two Tudor portraits in the NPG by optical microscopy is significant as red chalk is not visible in IR images that are usually interpreted as showing underdrawing where it is applied by the picture maker.
The interpretation of IR images is a challenge, and may be particularly crucial in the context of the present study, where the presence or absence of underdrawing using a range of materials and styles may provide evidence for defining the making and perhaps function of the works.
Practical issues for technical study include the opportunity for both holistic examination using high quality infrared (IR) imaging and X-radiography, as well as examination of paint and the order of application of materials that is best shown by the preparation of paint cross-sections. The possibility for taking suitable samples is limited from works that are varnished or in good condition, and may be more easily obtained from paintings during conservation. Characterisation of the organic media used for painting may also provide useful if not definitive data on different methods for picture making.
It may be important to identify the range of materials used for the works and to assess their condition, and also to define and classify material additions and subtractions to the works made during the history of the object and by conservators. Characterisation of material deterioration may also be useful in an assessment of contemporary and historical perceptions of the images.
Some modern advances in the technology for non-invasive (non-sample taking) methods for characterisation of pigments, such as X-ray fluorescence (XRF) may compensate for the limitations in samples available for the present technical study of Tudor paintings, providing more scope for identification of some pigments.
Evaluation of technical evidence in the context of historiography of the works is a challenge and new criteria need to be defined to advance understanding of the paintings in the study and of the period.