Hyperspectral image capture and analysis of The Scream painted by Edvard
Munch in 1893
Jon Y. Hardeberg1, Sony George1, Ferdinand Deger1, Ivar Baarstad2, Julio Ernesto Hernandez Palacios2
and Trond Løke2
1
The Norwegian Colour and Visual Computing Laboratory, Gjøvik University College, Gjøvik, Norway
Norsk Elektro Optikk AS, Lørenskog, Norway
2
Hyperspectral imaging of cultural heritage objects, such as paintings, has opened up new
possibilities for their analysis, visualisation, conservation, and documentation, and allows to
investigate the painting scientifically in a more precise way than any other existing techniques. This
paper presents the details of hyperspectral imaging studies carried out on Edvard Munch’s most
renowned painting The Scream (Woll 333) at the National Museum of Art, Architecture and Design in
Oslo, in collaboration with their paintings conservators. The spectral reflectance of 416 wavelength
bands from 400 to 2500 nm in the visible and infrared region has been acquired from both sides of
the painting. The rich information contained in the large number of spectral reflectance bands and
high spatial resolution in this study makes it the most complete and precise digital representation of
this painting till date.
The spectral reflectance has been recorded using the hyperspectral imaging systems HySpex VNIR1600 and HySpex SWIR-320m-e (developed by Norsk Elektro Optikk AS). The VNIR-1600 camera
generates 160 spectral bands in the visible and near infrared (VNIR) region of 400 to 1000 nm with a
spatial resolution on the painting of ~0.2 mm (for the whole paining) and 0.06 mm (for a subset). The
SWIR-320m-e camera produces 256 bands in the shortwave infrared (SWIR) region of 1000 to 2500
nm with a spatial resolution of 0.29 mm for the whole painting. An accurately controlled translator
stage moves the camera and illumination sources to cover the entire painting surface of size 91 x
73.5 cm. The image spectrum has been analysed during the acquisition and the camera parameters
has been optimised for signal-to-noise ratio. Lighting levels have been controlled and polarising
filters were employed to avoid specular reflections from the painting surface. We have
simultaneously captured a calibrated grey reflectance reference and Macbeth Colorchecker as
reference data for normalization and conversion to spectral reflectance.
The ongoing analysis of the spectral image data is expected to reveal many interesting details in the
painting. Infrared imaging goes beyond the upper layer of the painting and can reveal underpaintings, cracks and hidden information. This could also provide information about the previous
restoration works. We will be exploring the ‘see-through’ capability of the IR camera fully in this
research. A preliminary analysis of the SWIR spectral reflectance data showed the presence of
markings in The Scream which is not clearly seen in the visible region (Figure 1).
An important step towards conservation of this painting is to identify the pigment details. The
detailed reflectance spectra acquired for each pixel could enable classification of the type of
pigments and binders at a macroscopic scale non-invasively over the entire surface of the
masterpiece. Results of this study could play a vital role to visualise The Scream in its original color at
the time it was created. An important objective of this research is to create a toolset to digitally
simulate eventual restoration work of the masterpiece, and for instance support the conservators to
choose pigments for retouching, avoiding metamerism issues. Changes in visual appearance of the
masterpiece caused by aging of pigments or due to illumination changes can also be simulated and
visualized by different spectral processing methods.
Figure 1. The Scream (detail) acquired using (a) VNIR (b) SWIR spectral cameras.