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The technique of gamma-ray radiography has been used to obtain shadowgraphs of the internal metal framework (armatures) of several plaster and stucco figures. Both the technical and practical aspects of radiography of plasterwork have been considered, and while the gamma-ray sources 192Ir and 60Co may be particularly suited to very thin or thick subjects, respectively, a 137CS source of about one Curie is the most generally useful, and is capable of producing acceptable radiographs with stucco thicknesses up to about 50 to 60g/cm2. Laboratory tests using a 137Cs source showed that thickness sensitivities of 0·1cm of iron in 5·2g/cm2 of plaster, and 0·2cm of iron in a 32·5g/cm2 thickness of plaster, were attainable. It has also been found that wooden armatures (density about 0·7g/cm3) of diameter l·4cm can be detected in plaster of thickness 15·6g/cm2. Fieldwork has confirmed the results attained in the laboratory for wood and iron armatures; in addition features, such as cracks and density inhomog...

Blickling Hall in Norfolk is one of the best-known Jacobean mansions. Its south (entrance) and east facades (Figs 3 and 4) are outstanding pieces of architecture of the period and the rich emblematic plasterwork of the long gallery ceiling is justly celebrated. The date of its commencement, 1619, is carved in a prominent place in the entrance courtyard, and even the name of its architect, Robert Lyming, has long been known, for in the parish registers of Blickling his death in 1628 is recorded with the words ‘architect and builder of Blickling Hall’.