The BT 43 series consists of 432 large volumes containing patents and designs from the Office of the Register of Designs and Board of Trade, circa 1842 – 1885. The class contains 13 categories of designs. The range includes metal, wood, glass, fabrics, wallpapers, carpets, furniture and ceramics.

BT 43/68 was originally bound in a style known as an “Account guard book”. This is typical of the volumes in this series. The volume contains 911 designs, dating between 1864 and 1870. The designs were adhered to blank pages. Compensation guards were added into the sewing structure to reduce swell as designs were added.

The sections were sewn onto five paper-lined natural vellum tapes. A leather lining attached to the spine between the tapes. The storage conditions at The National Archives are ideal for archival material. However, the size of the volume (570mm x 330mm x 150mm) and its weight has contributed to its overall poor condition.

Damage includes a deterioration of the cloth joints at the spine and a loss of the spine piece. Boards have become detached and there is a general breakdown of the sewing structure. As a result, a number of the sections at the front and rear of the volume had sustained damage. This includes tears to the fore-edge, head and tail of each page resulting in quite severe damage to the items mounted on the page. Surface dirt and adhesive staining was prevalent throughout the volume.

The items mounted in the volume were of mixed media and size. This resulted in further problems. The problems include a range of different papers and card, photographs and small metal 3 dimensional pieces. Additionally there are drawings on tracing paper and waxed or oiled cloth.

Items were mounted onto the pages using a variety of adhesives e.g. animal glue and starch pastes. The amount of adhesive used varied considerably, especially towards the end of the volume. Mounting was haphazard with many of the items overlapping each other. Some became detached due to their size and weight. Others have been deliberately removed and reattached out of sequence. In places items had been attached to both sides of the page.

Approach to conservation and treatments

The main aim of this project has been to increase public awareness of the diversity of the material in the BT class. It was also intended to prevent further damage that may result from the increase in handling. To achieve this it was decided that the items should be digitised and the images made available online. The conservation approach would therefore consist of minimalist treatment. Preparatory work involved the complete dismantling of the volume, cleaning surface dirt from individual images and their removal from the backing sheets. Where items required more invasive treatments, a policy of minimal moisture was employed to protect vulnerable papers, inks and pigments. Fine splints of Japanese tissues and papers were used to support damaged areas. These were adhered with a wheat starch paste. In order to be unobtrusive, repairs where possible were applied to the reverse of the image. To facilitate handling, all photographic images and designs on fine tracing papers were encapsulated in polyester enclosures.

Although the conservation treatment of this piece has been completed, the final format for storage has not been decided upon. The original format is difficult to handle and produce. The decision will be made when digital images have been made of all the designs. To date the conservation treatment and preparation for scanning has involved 2 conservators and taken 906 hours. 911 designs have been cleaned and removed from their backing sheets. Of these, 461 items were conserved and 509 encapsulated.