Stranica 3 [3]
Foreword
In recent times, multispectral imaging technigues have increasingly become a part of the
range of examination and analytical methodologies that conservation professionals have at
their disposal for the investigation of cultural heritage objects. These technigues, which
include both luminescence (emitted light) imaging methods (ultraviolet-induced
luminescence (UVL); visible-induced infrared luminescence (VIL) and visible-induced visible
luminescence (VIVL)) and a range of related broadband reflectance imaging methods
(visible reflectance (VIS), infrared reflectance (IRR) and ultraviolet reflectance (UVR)), are
not only used by scientists but are also increasingly being adopted by a much wider range of
users including conservators, archaeologists and curators, in more diverse and challenging
settings. However, although attractive in offering qualitative, non-invasive and often relatively
inexpensive and portable tools for spatial localisation of specific materials or material types,
the equipment, capture and processing of images — particularly those used in luminescence
imaging — have tended to be highly dependent on individual users and the set-up they
employ, making cross-comparison between different institutions and researchers very
difficult. It has thus become evident that there is a need to establish a clear set of widely¬
accessible methods and protocols from which to work.
As part of the CHARISMA project (Cultural Heritage Advanced Research Infrastructures:
Synergy for a Multidisciplinary Approach to Conservation/R estoration,
htto://www.charismaproject.eu/), research has been undertaken to develop new optimised
methodologies for the acquisition and processing of images in order to investigate the 2D
and 3D distribution of organic and inorganic materials on art objects. The CHARISMA
project, funded by the European Union FP 7 Research Infrastructures programme (Grant
Agreement no. 228330), is a unique consortium of 22 leading European institutions working
together to develop and promote best scientific practice for the interdisciplinary study of
cultural heritage and to disseminate this knowledge.
In developing new optimised multispectral imaging methodologies, emphasis has been
placed on using equipment that is readily available and distilling the work carried out into a
set of user-friendly practical materials and resources, which are aimed at a wide range of
users and are as broadly accessible as possible. In this way it is hoped that these are not
only widely adopted by the cultural heritage community but also address the needs of users
beyond it.
The approach adopted in this work built on previous work undertaken at the British Museum
by two of the authors and has centred on understanding the experimental factors and
phenomena that can lead to those device-dependent issues experienced by users that may
inhibit these comparisons. The optimisation and standardisation of experimental procedures
and acquisition protocols was addressed as a first step towards reducing these issues and
improving reproducibility and inter-comparison between the resulting images, both within and
between institutions/users. Additionally, as a response to the limited guidance which is
currently available on image post-processing methods, work was undertaken to develop
robust image calibration and correction protocols and to create freely available (open¬
access), easily applicable post-processing software tools.