RESTORATION
The craftspeople commissioned to create Tu Duc's tomb were well aware of the dangers of their climate and thus developed decorative elements from glazed architectural ceramics, porcelain mosaic, fresco painting and extremely stable mortars. The advantages of such techniques were wiped out in part by structural shortcomings however: the small canopy of roof-tiles atop the gateway at the tomb's entrance did little to prevent rain-soaked mortar from gradually encrusting plaster and ceramics with calcite deposits, and thus helped create a perfect environment for micro-bacterial infestation. The conservation and restoration of the gateway and spirit screen fully comply with UNESCO standards and the internationally ratified principles of the Venice Charter. A thorough analysis of historic components and techniques and of different types and causes of damage precedes all practical on-site work and constitutes its scientific basis. The measures undertaken at Tu Duc's tomb represent primary research into modern conservation materials and methods for outdoor architectural monuments. Their aim is the long-term preservation of original substance. Recommendations on the entire mausoleum site will prioritize the use of materials that are available in Vietnam and easily handled. Already, local workshops are being encouraged to manufacture a broader range of glazed ceramics and the market for buffalo-hide glue, precious lime and paper made from the 'do' tree is likely to grow. Successful examples of conservation and restoration such as Tu Duc's gateway and spirit screen encourage local craftspeople to rediscover the benefits of traditional construction methods.