The Building Conservation Directory 2022

160 T H E B U I L D I N G C O N S E R VAT I O N D I R E C T O R Y 2 0 2 2 C AT H E D R A L C O MM U N I C AT I O N S substantial improvement without detriment. Unlike surveying, for example, where modern technology contributes significantly without leaving any trace of its use, physical interventions will impact on the project’s historic authenticity. As a result, the repair of historic features still largely relies on traditional process, authentic materials and fine craftsmanship. Newly produced pieces have to sit alongside or be embedded within the historic originals being preserved, so they must have the same depth of character and their form must speak of the craft processes that produced them. So, finding a home for digital technology in these historic methods of production is perhaps not as straightforward as in other areas of conservation. 3D printing’s extruded plastic forms, for example, have certainly found use in model making and visualisation, but have seemingly little or no role to play in restoring, or repairing historic features. While it can generate form, its extruded synthetic structures offer nothing to a process seeking authenticity and historic validity. With CNC, however, we have seen some interesting developments recently. CNC AND ITS LIMITATIONS In CNC machining (the letters stand for ‘computerized numerical control’), material CNC cutting of timber to reveal a ‘near-form’, ready for hand carving is accurately removed by a cutter which is positioned and moved in two or three dimensions automatically, following digital co-ordinates defined using CAD software. The process has become common in modern furniture design where it plays a valuable role as a fast, but heavily compromised alternative to traditional hand carving. Features are soft and undefined, and the organic quality of hand craftsmanship is entirely lost. As such, features formed by CNC alone are rightly viewed as a heavy compromise, sacrificing significant quality for savings in time and budget. With traditional handcraftsmanship and historic process absolutely vital to authentic and successful historic restoration, it might appear that digital process has no role to play in conservation production. Yet, with a fresh perspective, new approaches can harness the best of both worlds. Digitally driven CNC can bring great efficiency and accuracy to the organised removal of bulk material, taking timber down to a near-finished form, ready for traditional hand carving to find the final surface. This highly accurate and repeatable method of voiding unwanted material leaves craftspeople free to focus their skills on carving the final surface, finding the crisp final form, full of the visual language of hand-carved wood. In many ways this process mirrors a traditional team of assistants, working through the same lengthy processes of reduction before handing over to the master craftsperson for the most skilful final stages. Equally, it can be seen as a logical continuation of the use of mechanised tools in the assist with voiding bulk material. Craftspeople have always used whatever technology was available to them to aid them in their work. From the pre-industrial harnessing of water power to drive sawmills, to the introduction of electric routers, bandsaws and planers, our reliance on hand tools alone has slowly diminished, enabling faster conversion, voiding and preparation of material. CNC can simply be seen as another development in the tools crafts people use to better facilitate their craft. It is perhaps time for the modern conservation workshop to embrace and value digital technology for what it can add to a project when used with consideration and partnered with skilled craft. From a craftsperson’s perspective, utilising digital technology in this way removes multiple stages of effort, previously necessary to prepare block timber for carving in fine surface detail. It gets the craftsperson to the fine detail stages much more quickly. It avoids wasting