Museum lighting must satisfy a broad range of criteria but, most critically, needs to make museum objects visible (with an appearance matching specific constraints), whilst preserving them as much ...

The ‘Oddy test’ is an accelerated corrosion test introduced in the 1970s at the British Museum to identify materials likely to emit volatile substances that could harm museum artefacts. It is carried out in many museums all around the world, but not always using the same methodology, which makes it difficult to compare and share test results between institutions. Refinements to the Oddy test methodology have been implemented at the British Museum over the last decade and the aim of this paper is to present these and promote consistency across institutions. The modifications introduced concern the method used to wash the glassware, the preparation of the metal coupons, and standard methods for preparing samples of liquid coatings, adhesives, and adhesive tapes. Finally, conducting Oddy tests is time consuming and measures employed at the British Museum to reduce the number of materials to be tested and streamline testing are described.

Laser cleaning tests were performed on five archaeological copper alloy objects using a Q-switched Nd:YAG laser at 1064 nm. As a comparison, a section of each object was cleaned mechanically. Prior to cleaning, cross-sections were prepared to characterise the corrosion crust and help to locate the position of the original surface. Laser cleaning was not successful at removing burial deposits on two of the objects. For the other three objects, the laser removed most of the corrosion crust. This was not always satisfactory, as cleaning was sometimes accompanied by the loss of the original surface. In addition, laser-cleaned surfaces were matt compared to mechanically cleaned surfaces. In some instances, the former had a disfiguring purple hue which was attributed to the formation of particles that could be seen when examining the surface using scanning electron microscopy. For all the objects examined here, superior results were obtained by mechanical cleaning.

The British Museum has in its collections a magnificent Byzantine ivory panel. However, the panel has become warped over time and there is a join on the left side, where it has suffered a break in the past. It has been connected with two metal pins and adhesive in a previous conservation treatment but there is now concern that these could be having an adverse influence on natural movements within the ivory. Given the importance of the panel, the decision was made to leave the pins in place and monitor the stability of the panel. As the geometry of the panel is complex, it was felt that microscopic imaging would not be suitable and 3D laser scanning was used instead. This engineering metrology technique is increasingly used in cultural heritage and conservation to record minute three-dimensional changes with high spatial accuracy. The resulting dataset is a detailed metric 3D record of the object surface in-the-round and comparison of subsequent scans with a reference scan can indicate dimensional changes. As part of a monitoring campaign, the ivory panel was first scanned in January 2012 to provide a reference scan. It was then scanned again in autumn 2012 (no significant movement was detected) and will be scanned at regular intervals in the future. This case study demonstrates the potential of 3D laser scanning to monitor the dimensional stability of complex artefacts.

Ukiyo-e Japanese woodblock prints were mass-produced in the Edo Period and early impressions of a given print are generally of higher quality and more sought after by connoisseurs than late impressions. The present publication presents an innovative approach that combines the classical method of examining line quality with a systematic study of colourants. This approach was used to compare an impression of Hokusai’s iconic ‘Red Fuji’ with its rare variant, ‘Pink Fuji’. Woodblock wear and printing effects were studied using high resolution photographs and the colourants were characterised using non-destructive methods. Signs of greater woodblock wear were identified in ‘Red Fuji’ compared to ‘Pink Fuji’ and there were indications that much more thought had been given to the selection and application of the colourants in ‘Pink Fuji’. This showed that ‘Pink Fuji’ was printed before ‘Red Fuji’ and is possibly a first edition. The approach developed here represents a novel way of studying Japanese woodblock prints and can be used to determine the sequence of impressions of other prints.