January 1993 Issue 06
Assessment RCA/V&A conservation course: science for conservators
No. 3 of this journal included a discussion of the assessment procedures for students on the RCA/ V&A Conservation Course and a promise that more abstracts from essays prepared for assessment would be forthcoming. This promise is now kept but in a rather particular way. The abstracts provided on this occasion refer only to Science Essays, rather than History of Art or Design or Techniques and Materials Essays and a few words of accompaniment are necessary - to explain how these essays fit into the assessment procedure for RCA/V&A students and to explain why only five abstracts are provided when twelve MA students have been 'scientifically assessed' to date.
The abstracts provided essays written by students who have joined the Course in practical disciplines (rather than as research students) but who begin (unlike many practical conservation students) with a 'reasonable level of scientific education.' In three cases, these students are two year MA students who have previously completed courses in paper conservation and, in so doing acquired much of the paper and cellulose chemistry they need alongside the basic science. One student has turned to conservation as a new career but has a scientific education and several years of laboratory experience. One has a chemistry degree as well as a diploma in conservation and restoration. It seems appropriate to allow such students the opportunity to prove and improve their level of scientific awareness and understanding by selecting for assessment essay titles or questions which are of particular interest to them as specialists, rather than by setting a general science examination of any description. Hence a trained paper conservator specialising in historic wallpapers turns to the chemistry and physics of salt and moisture movement in walls or to the movement in walls or to the colouring materials used in wallpapers and their potential degradation. Similarly, a student new to textiles conservation but with a background in biochemistry and microbiology can usefully discuss detergents and detergency, rather than atoms, molecules and the periodic table.
Of course such students are not excused further scientific education as part of their course. They select, after discussion with tutors, those elements of the core science syllabus which are of use to them, either as revision or as new and relevant material. Further, they have the opportunity to invite specialists from outside the South Kensington 'campus' to give seminars on scientific subjects of relevance to their practical work. For example, the aforementioned textiles student may reasonable miss all basic science seminars but is expected to attend all the seminars on the science of individual materials - stone, ceramics, metals, wood, paper and so on - as well as those on textiles. This is feasible in a three year course and encourages a more general and comparative understanding of the behaviour of materials in objects. Such a broad understanding is useful to a conservator, however specialised their practical discipline. For purposes of assessment, however, a much more focussed subject is acceptable.
Students who cannot claim such scientific 'competence' at the beginning of their Course will be a more familiar 'species' to the conservation trainer, at least in the UK. Although it is some years since I was obliged to select my A level subjects, I doubt that the character of our education system has changed very considerably in its perception of pupils who would prefer not to have to abandon either the arts or sciences - who frankly want to do both. They are aberrant, schizophrenic, unwisely reducing their chances of success in the sciences because of their wayward interest in the arts or vice versa. Conservation, however, has need of such people. It is a profession which best suits those who do not wish to be polarised towards the arts or sciences.
One of the new students who started in October did, in fact, choose Maths, Physics and Art at A level, followed by a degree in Design but this is an exceptional combination. Her interest in conservation now reflects a technical and scientific interest in metals and metal working techniques that her degree course has not fulfilled, and she could not visualise a career after graduation as a dedicated designer. Colleagues in conservation training will no doubt recognise the appeal of such details in a CV and regret there are so few examples in their annual batch of applications. How often do we see applicants with joint degrees in chemistry and art history, or physics and sculpture?
Perhaps the evolution of Conservation and Restoration degree and pre-diploma courses in the next few years, (other than those already established in archaeological conservation) will have a dramatic effect on the educational profile of applicants for existing postgraduate courses in fine and decorative arts conservation. It will be interesting to see.
To return, however, to the subject of scientific teaching and assessment for the many non-scientific students who do become involved in conservation training, what exactly are the aims? Can we turn non-scientists into thoroughly trained scientists within a two or three year course, while, of course, they simultaneously become art historians and highly skilled, experienced practical conservators? Surely not. In the guidelines for staff who teach science seminars for the RCA/V&A Course, many of whom are pure scientists rather than conservators, three basic aims are stated. Graduates from the Course should be able to:
Communicate in an intelligent and articulate fashion with scientists involved in identification, dating and analysis of the materials with which they are concerned or in other aspects of scientific conservation research
Understand science-based lectures and publications on conservation topics, particularly in the recognised conservation literature
Understand the implications of their work as regards the chemi cal and physical changes which may arise from the methods and materials they use and from the conditions of display, transport and storage.
The ability of students to do these things is assessed throughout the Course in tutorials, progress meetings, studio visits and oral examinations. It is necessary, however, to make some formal assessment of how the non-scientific student is coping with the heavy dose of basic and materials science administered during the first year. This is achieved, as previously explained, by essay rather than by unseen examination. The challenge has been to set essay titles or questions which explore the non-scientific students' developing understanding of first principles - atoms, bonding,
polarity etc. - but also the ability to apply these principles to real materials and to conservation problems. With this in mind, multi-part questions have been set, or questions have been devised which aim to manoeuvre the student from the properties of the atom to the properties, and problems, displayed by the museum object.
Of the sixteen students currently on the Course, three are MPhil students and are not assessed other than on the quality of their research work and its presentation. Five have been considered competent to undertake essays of a specialised nature on subjects chosen by themselves or in consultation with their tutors. Abstracts of these essays are provided below. The remaining seven students have endured essay questions of a more general nature. It might be interesting for the reader to see examples of these general science questions but unfortunately space prevents their inclusion on this occasion.
Abstracts for student science essays on specialised subjects 1990/91 and 1991/92
MA Furniture Conservation
October 1990 - October 1993
Four short essays: An examination of the new methods
of cleaning painted and decorated surfaces by Richard Wolbers
1873 words, 4 diagrams
The basis of Richard Wolbers work is that if the binding media (i.e. oil, natural resin, protein etc.) of the various layers making up a comlex surface coating can be identilied using staining and fluorescence, it is possible to exploit these differences between the layers and to select a specific reagent to remove a specific layer in a control-led and predictable way without affecting the underlying layers. The various cleaning materials employed i.e. enzymes, solvent gels, resin soaps and emulsions of solvents are examined, as is the problem of clearance i.e. the removal of the residue left on a paint surface by a cleaning material.
An examination of the fluorochromes used in the identification of binding media
430 words, 3 diagrams
The binding materials present in the various layers of a complex surface coating can be characterized by the application of direct reactive fluorochromes applied to the cross-section. The use of several fluorescent stains is discussed including fluorescein isothiocyanate, rhodamine B, fluorescamine, triphenyl tetrazolium chloride and antimony pentachloride.
An examination of some traditional surface coatings
740 words, 4 diagrams
The essay reviews the chemical structure, on and drying processes involved for some of the more common traditional surface coatings i.e. linseed oil, shellac, dammar and mastic resins.
An examination of the hydrocarbon solvents derived from petroleum
521 words, 3 diagrams
There is a wide range of hydrocarbon solvents obtained by the distillation of petroleum. The essay considers briefly how solvent properties vary according to the particular kinds of hydrocarbons they contain, their structure, molecular weight and proportions.
MA Conservation of Photographic Materials
October 1991 - October 1993
Prints and Permanence: A review of 19th century photographic processes with particular regard to the chemical stability of the image
Approx. 3500 words with a bibliography and summary tables of photographic processes with their dates of use
All 19th century photographic processes are based on the principle first employed by Daguerre - the exposure of photosensitive salts of stable metallic elements to light in order to capture an image. The essay begins with this principle and explains how it can be used m a developing out or printing out process. A brief discussion of the general factors affecting the stability of the photographic image is provided, stressing that a combination of factors rather than any single factor is usually involved. The main body of the essay provides a methodical account of the twenty six processes in use in the 19th century with notes on their intrinsic permanence and the external factors most likely to affect image stability.
MA Textiles Conservation October 1991 - October 1994
Synperonic N: Due to EC regulations Synperonic N may be banned in the future on environmental grounds. Discuss the properties of Synperonic N that have made it so popular and the criteria which will influence the choice of a replacement
Synperonic N has been a particularly popular detergent for use in textile conservation. The essay begins by listing the reasons for its popularity, as a starting point for the selection of alternatives. The general properties of detergents and the principles by which they work are then discussed and the classification into anionic, cationic, amphoteric and non-ionic groups is explained. Subsequent discussion is limited to the anionic and non-ionic groups - being of most relevance to the conservator. These are discussed in some detail with tables indicating the most common chemical types. Specific reference is made to those which have found use in conservation, such as sodium dodecyl phosphate (SDS) and Synperonic N itself. Some potential alternatives are cited. The subject of biodegradability is addressed again in the closing discussion but the essay also asks where non-biodegradables should be permissible in the EC for the treatment of historically important objects, given the small scale usage involved.
MA Conservation of Historic Wallpapers
October 1991 - October 1993
The Movement of Active Salts in Walls Decorated with Wallpapers
Approx. 4500 words with 4 diagrams and 2 tables
The majority of the essay addresses the question of moisture movement and salt formation in walls in general, turning in the closing pages to the particular situation involving wallpapers. First, the possible sources of water in the walls are considered. The importance of condensation, not only on but within the wall, is stressed. The origin of the various salts which may be involved is then discussed together with the mechanisms by which these salts may be transferred in solution from one place within the wall. While the presence of moisture, salts and solutions (particularly of an acidic or base character) can be important in deterioration, it is the process of recyrstallisation or efflorescence which is of most concern. The essay considers briefly the particular dangers involved and the various terms of importance, including fractionation, cryptofluorescence, crystal morphology, equilibrium RH for various salts, evaporation and diffusion processes and thermal expansion. The essay concludes by stressing the damage caused by cycles of solution and precipitation and the importance of stabilising RH and temperature. It explains that solving the problems of moving damp and salts in walls may be complex and expensive, requiring consideration of the whole building structure and surroundings.
MA Conservation of Historic Wallpapers
October 1991 - October 1993
Pigments used on Historic Wallpapers from the 17th century to 1835 and their Possible Degradation
Approx. 3500 words including an appendix on colour production
Historic wallpapers share many of the materials used in watercolour painting but tend to be exposed to environmental conditions common for mural paintings. While little has been written specifically about the deterioration of colours in wallpapers, it is therefore relevant and useful to review the available information on these other media. The essay provides a summary of the materials involved and considers the deterioration process for a range of organic and inorganic colours. It is pointed out that in some cases the important factor is the cation, for example in copper containing green pigments, while in others deterioration is more closely linked to the anion, as for chromates and carbonates. For organic colours, the mechanism for fading involving the reaction of the dyestuff in its excited state with moisture is discussed. The susceptibility of pigments and dyes to change in acid and /or alkaline conditions is stressed together with the importance of moisture in the majority of mechanisms involved.