The National Gallery holds a large archive of documentation from technical examination and conservation of its world-class collection of western European paintings. This includes many iconic works, ranging in date from 1200 to around 1900.

The National Gallery holds a large archive of documentation from technical examination and conservation of its world-class collection of western European paintings. This includes many iconic works, ranging in date from 1200 to around 1900. The uniqueness of the archive lies in the quality of the paintings that it relates to, the long period of time over which it has been amassed, which makes it extensive, as well as the quality and variety of the data. The conservation records date back to around the middle of the nineteenth century; from the late 1920s onwards technical images were being made (x-radiographs and infrared images of various kinds) and now number several thousand; the collection of paint samples from works of art and the associated reports, images and data have been amassed from 1949 onwards and is also very extensive. NG also houses a historical archive in its Research Centre, which has a catalogue that is searchable online and includes information of value to heritage science researchers, especially on history of conservation and scientific examination of art; this has been requested for consultation during the CHARISMA and IPERION projects. An important part of the transnational access that has been offered in CHARISMA and IPERION is that the users do not only consult the documentation but are also able to benefit from the time and expertise of NG scientific staff, who guide them through the documentation, helping with interpretation and suggesting comparisons that would be relevant through having a familiarity with the contents of the archives, complemented with study of the relevant paint samples under the optical microscope together with the visiting researchers. The archive concerns documentation on Western European paintings from around 1200 to around 1900. The documentation includes: Visible light images (high resolution of whole paintings; historical conservation records; photomicrographs of paintings); Various types of technical images (Infrared photographs from 1930s onwards, Infrared reflectography from 1990s onwards, Digital infrared reflectography from 2006 onwards, Hyperspectral images and data, X-radiographs, maps derived from macro XRF scanning data); Chromatographic and spectral analytical data; SEM-EDX, FTIR, XRF (point analyses and scanning), X-ray diffraction, GC-MS, HPLC of dyestuffs – both on samples from paintings and reference samples; Records/reports on technical examinations and analyses, conservation treatments, preventive conservation etc.