Oxford Authentication Ltd
Boston House
Grove Technology Park
Wantage Oxfordshire

Tel: +44 (0) 1235 770998
Fax: +44 (0) 1235 771021




Our hours are Monday to Friday, 8.30-4.30. Please leave a message on the answer phone if there is no-one to take your call. We will get back to you. Please note that visits to the laboratory are by appointment only. OX12 9FF, UK

Oxford Authentication Ltd was formed in 1997. Since its formation, we have performed over 18,000 tests. Clients come from all parts of the world, and include major museums, auction houses, dealers and collectors. The company is international, with representatives in Hong Kong, the USA and Europe, as well as in countries such as Australia, New Zealand, Israel and South Africa.

Our thermoluminescence (TL) laboratory has state-of-the-art equipment. There are three fully automated, computer-operated Riso Minsys TL readers that are constantly updated, and we have twelve Elsec alpha counters. The alpha and beta sources, integrated in the TL readers, have been fully calibrated in collaboration with workers in Australia and Munich, and the dose-rate adjusted each year. Since the TL signal can be very faint in some samples, the photomultiplier tubes in the TL readers are specially selected to be most effective.

Care in sample preparation is absolutely crucial. Our preparation facilities include two Buehler low speed diamond saws for cutting porcelain, a range of drilling equipment, plus a high specification fume cupboard, drying oven and centrifuge .

What sorts of piece can be tested?

We can test fired clay.
Casting cores of bronzes.

Analysis of our results shows that 92% of our tests either give ages consistent with those expected within the 20% limits or the piece is modern. The results of another small percentage of the tests lie just outside the 20% range, and there is little doubt whether these pieces are ancient or modern. Of the remainder, some cannot be dated because of problems with the material sampled: there may be a spurious signal (see below), or there is contamination, or the samples are too insensitive to radiation. Other pieces will have been misattributed. Occasionally, pieces have to be re-tested.

In authenticity testing, usually we want to distinguish between modern copies and original pieces. So one important question is when the modern copies might have been made. If there were no modern copies until the 20th century then, providing the sample is sensitive and we do not obtain a spurious signal, the practical limit for a trustworthy test is the 18th century. We regularly test Kangxi porcelain, and Staffordshire ware pottery. Italian Renaissance pieces are more difficult. Here the pieces were frequently copied in the 19th century and so that even these 19th century copies have a TL age. The latest pieces in this case would be the 17th century for reliable testing.

Pottery Sampling :
If you would like your pottery item tested, get in touch with us via our contact form. We will need to know where the piece is located so we can recommend the closest sampling agent to you, or arrange to come and sample it ourselves. We will also need to know what type of piece it is, for example a Pre-Columbian pottery figure or a Chinese porcelain vase. All sampling is carried out in a darkened room by an accredited agent.
We need a 100mg sample of powder from an inconspicuous area of your object. This leaves a hole the size of the tip of a pencil lead. It is usually necessary to take more than one sample to check that there are no restored areas and that different parts of the piece are made from the same clay.
An image of the piece must be submitted with the sample. This may be an actual photo, or on a CD or emailed to us by the agent.
Details are entered onto a data card which is sent along with any photographs and the sample(s) to our laboratory for testing.

After we have tested your piece, we will issue you with a one-page report. Samples are normally processed within three weeks and once payment is received, preliminary results are emailed or faxed. Original reports will then be posted to you.

Porcelain Sampling :
All sampling is carried out by in a darkened room by an accredited agent. See photograph for an example of removing a core sample from porcelain.

Porcelain is fired to a higher temperature than pottery. It is so hard that we cannot use the same kind of drill to take samples as we do with pottery. Instead we use a hollow diamond core drill to remove two cylinder shaped cores from the base or other unglazed part of the object. The cores are 3-4mm in diameter and 5mm in length. All sampling is carried out under running cold water to stop overheating the cores.
An image of the piece must be submitted with the sample. This may be an actual photo, or on a CD or emailed to us by the agent. Details are entered onto a data card which is sent along with any photographs and the sample(s) to our laboratory for testing.

After we have tested your piece, we will issue you with a one-page report. Samples are normally processed within three weeks and once payment is received, preliminary results are emailed or faxed. Original reports will then be posted to you.











20 Rutland Gate,
London SW7 1BD .
Tel: 020 7589 4128
Fax: 020 7581 9083



This is probably the most complete independent assessment available but it comes at a price. It is particularly useful if you believe what you have purchased is a fake. The description below is from the B.A.D.A. website.

You own what you believe to be a valuable antique, but you are not really certain what it is. Why not take advantage of The British Antique Dealers’ Association Antiques Assessment Service? This service has been offered for many years to any member of the public who needs to obtain confirmation as to the age and appropriate description of an antique object. The service is NOT a valuation service; valuations can be carried out by those BADA members who provide such a service (see Dealer Search).

At least three experts are appointed by the Association to inspect items submitted under the Service. They are usually willing to comment upon existing descriptions of items or to provide a description where none existed previously. There is a charge for the service (see below). The Assessment Service is provided to members of the public on the following conditions: * In most cases, for items to be examined they must be delivered at the owner’s expense to the Association’s headquarters in Knightsbridge, London. The items are insured up to a maximum level whilst on our premises. * The BADA undertakes to any person using the BADA Assessment Service that the object in question will be examined by a panel of not fewer than three experts who will provide an opinion in writing as to the age, appropriate description and authenticity of the object. * Every opinion is given in good faith after an inspection and examination carried out with due diligence and within the current boundaries of knowledge. It must be clearly understood that since the views of experts often differ in attribution and identification neither the BADA nor its panel members can give any warranty as to the complete accuracy of any opinion expressed. * The BADA Assessment Service operates subject to the above conditions and anyone using the Service will be assumed to have accepted them. To take advantage of this service, please apply to the BADA (see Contact) for an Assessment form, which should be completed and returned to the BADA together with a cheque or draft drawn on a UK bank payable to “BADA” for sterling £293.75 (inclusive of VAT). You would also be advised to telephone us to discuss the item first, so that our staff can assess its suitability for the Service. In certain cases, by prior arrangement, the item can be examined on the owner’s premises in which case the fees for this are £587.50 (inclusive of VAT) plus travel expenses as incurred. Upon receipt of the completed form the BADA will then contact you to arrange a time for delivery of the item to our premises.








The Conservation Register makes information available on conservation-restoration businesses providing commercial services in a variety of specialisms. Businesses apply voluntarily to be part of the Register but must meet the criteria for inclusion to be accepted. The information on each business is reviewed approximately every two years to ensure that it continues to meet the criteria for inclusion and remains up to date.
The Conservation Register is currently in the process of introducing the professional standards of accreditation as a requirement for inclusion. All businesses included in the Register are either already led by a professionally accredited conservator, or should be working towards such status. The accredited status of an individual conservator is shown on the ‘staff’ pages of each workshop/business entry. For further information on accreditation, please see the Guidance section.
The Conservation Register is owned and operated by the registered charity the Institute of Conservation. It was first set up in 1988 by the Conservation Unit of the Museums & Galleries Commission.






Mr. Bouke de Vries.
Mobile +44(0)77 65 256 660



Bouke De Vries has worked in the conservation and restoration of ceramics, glass and related materials since 1993. His practical experience covers everything from archaeological earthenware and Roman glass, to fine porcelains and contemporary pots. Clients include private individuals, premier auctions houses, national and regional museums, other heritage organisations and private sector institutions. The workshop offers a full range of conservation services, such as: interventive and preventive conservation, collections management, collections surveys and occasional lecturing and training in the UK and Europe. Bouke gained accredited status in 2002.

In this flawed world perfection seems to be an attainable goal – for example, the body of Governor Schwarzenegger, or the self-made Catwoman, Mrs Wildenstein. But not-quite-perfection is often easily dismissed and discarded. As a ceramics conservator Bouke de Vries is faced with issues around perfection on a daily basis. Where even an almost invisible hairline crack, a tiny rim chip or a broken finger render a once-valuable object pratically worthless, literally not worth the cost of restoring. There’s something incongruous about the fact that such an object, although still imbued with all the skills it took to make it – be it first-period Worcester, Kang-xi or Sevres – can so easily be consigned to the dustbin of history. The Venus de Milo is venerated despite losing her arms. Why not a Meissen muse?
Moreover, even when an object is ‘worth’ restoring, some owners prefer to hide the damage as much as possible, to deny the evidence of what was probably the most dramatic episode in the life of the piece. Especially since modern methods mean other options are available. (Interestingly, the rocketing auction prices of Pablo Picasso’s hand-painted ceramics are beginning to make a difference here. As are the much-worked surfaces of pots by Turner prize winner – and de Vries client – Grayson Perry.) In his new series of ‘exploded’ artworks de Vries is reclaiming broken ceramic pieces after their accidental trauma. Instead of reconstructing them, he is de-constructing them. Instead of hiding it, he emphasises their new status, using his honed conservator’s skills (compare Ron Mueck applying his skills learnt as a model maker) to instil new virtues, new values, and to move their stories forward. The spaces in between the fragments become an essential part of the structures and the objects sometimes take on a cubist quality. With some works the viewer may be confused as to where the original makers of the piece stop and where the artist begins, making the work biographical and giving it new currency.

More contemplative works echo the 17th- and 18th- century still life paintings of de Vries’s Dutch heritage, especially the flower paintings of the Golden Age, a tradition in which his home town of Utrecht was steeped – by such artists as de Heem, Kalf, van Alst and van Huysum – with their implied decay (and stories of the slow-working artists’ studios stinking of their real-life decay) and by incorporating contemporary objects a new vocabulary of symbolism evolves. The still lifes give everyday household objects – a milk jug, a teapot, a cress drainer – a certain poignancy with references to the vanitas and memento mori paintings of that period. An installation in de Vries’s London house is arranged in the manner of Daniel Marot with white Delft domestic pottery rescued in fragments from Dutch rubbish tips of the 17th and 18th centuries, now dug up and partially pieced together.







Paper Conservation
Merton Park, London SW20
Tel: 020 8543 2585




The Diana Washington Paper Conservation Studio was established in 1988 as a result of a large commission from the Ashmolean Museum, Oxford, to conserve over 500 Pissarro prints, drawings and watercolours (funded by the Getty Foundation). The Studio provides expert help with all types of art on paper; from prints, drawings and watercolours to pastels, maps and archives. We undertake work for private owners, galleries, picture framers, picture dealers, museums and institutions – from single items to collections. Diana Washington trained at the Camberwell College of Arts. She is an Accredited Member of the Institute of Conservation; an Associate of the International Institute for Conservation of Historic and Artistic Works; a Member of the Independent Conservators’ Group and is listed on the Conservation Register, maintained by ICON.