From Fabrication to Conservation: Numismatic Engraving
17 JULY 2018
By Stirling Kain
Claire Rowson, Grimwade Centre student conservator and numismatic engraver at the Perth Mint, explores many aspects of numismatic creation and conservation in her role. The main topic of her address at the WA Shipwrecks Museum on November 30 was die-making innovation and the consequences of this. Coin dies, being essential in coin creation, stamp impressions on a piece of metal to create a coin, and although their construction process may have changed over time, their importance remains. A dynamic and progressive tutorial, Claire communicated her desire to push the world of numismatic conservation into the future in a historically-minded industry.
Claire noted that since the 1950s, when there were 4 reducing machines at the Perth Mint, this method of die creation has become increasingly outmoded. The electronic process, involving digital sculpture and CNC machining has been developed within the last fifteen years. Like the plaster method, the electronic procedure begins with an artistic sketch. This is then modelled in digital sculpting software and the metals, sizes, weights and reliefs are considered.
Claire has been involved in the creation of coins as small as 0.5grams and as large as 10 kilograms, stressing that every coin is different thus review of previous work is paramount. Modelling software allows designers to sculpt a coin design until the digital sculpture most closely resembles the two-dimensional sketch. The digital sculpture is then given its finishing touches, those being further sculpting, adding a convexity to the coin, and adding a coin rim. The finalised digital sculpture is transferred into the cutting machine, and from here, the electronic process mirrors the plaster process concerning the use of a reduction machine and steel to make dies.
Claire communicated that the plaster and electronic processes each have highlights and shortcomings. The new technique allows engravers to create more detailed coins in a matter of days, emphasised by Claire as a positive innovation, whilst coins took up to six months to be created with the plaster technique. Despite the computerized aspects of the electronic method, the process still requires human input as evidenced from the method description. Claire also mentioned that despite the electronic method being a more viable option in a modern production context, a community exists that still values hand-sculpted designs in plaster, making the associated skills and materials worthy of conservation efforts.
Stirling Kain is a conservation volunteer at the Western Australian Museum. Frst published in the AICCM newsletter, March 2018.