International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Volume XL-5/W2, 2013 
XXIV International CIPA Symposium, 2 — 6 September 2013, Strasbourg, France 
which was not used in this case. 
The hyperspectral instrument is placed on a medium 
size motorized moving platform designed by Headwall 
Photonics, Inc. named Pan&tilt [15], that provides accurate 
real-time positioning of the hyperspectral equipment. The 
imaging spectrometer has been calibrated by the manufacturer. 
Illumination was a big issue when dealing with 
historic paintings. The temperature of the painting must not 
exceed 35°C, which was monitored using thermometer. 
Illumination was accomplished by two 500Watt Halogen lamps 
supplemented with one 150Watt infrared bulb. 
3. PAINTINGS 
Two different paintings were examined. Both pieces 
of art are oil paintings on wooden board. This combination was 
chosen because of the possibility of underdrawing visualization 
which is supposed to be the most uncomplicated painting 
combination for this type of analysis. 
The first chosen painting for the analysis is by 
David II. Teniers and it belongs to the best that Flemish 
classical 1 7th-century painting can offer. Teniers painted almost 
every kind of picture, but chiefly genre scenes of peasant life, 
which is typical subject for this historical period and the area, 
many of which were subsequently used for tapestry designs in 
the 18th century [16]. He was born in 1610 in Antwerp to the 
family with a long artistic tradition. His father David Teniers 
the Elder was respected painter, influenced directly by misters 
such as Rubens or Elsheimer. Early works of David II. Teniers 
shows also the influence of Adriaen Brouwer. He has achieved 
a great success already during his lifetime. Besides his 
prestigious position of the court painter of the Archduke 
Leopold Wilhelm, he was appointed as a keeper of the 
collection of pictures the Archduke was then forming. Finally 
he was of the prime movers of the foundation the Brussels 
Academy of Fine Arts (1663) and subsequently the Academy in 
Antwerp (1665). His artwork belongs to the golden age of 
Flemish and Duch painting. Especially his early works are of 
significant high quality. They are characterized by extreme ease 
of painting, fascinating effects of lights and shadows, perfect 
sense for detail, astonishing amount of acquired knowledge and 
natural good taste. All of these characteristics are relevant for 
chosen painting “Interior of a Mill”. This oil on panel painting 
of medium size is dated 1633 approximately. It displays an 
interior of the old mill with a small figure in the background. 
We can notice the significant sense for detail and very delicate, 
limited range of colors. However Teniers was very skillful 
painter and his production was enormous. There are over 900 
paintings accepted as original productions of Teniers. Few 
artists ever worked with greater ease, and some of his smaller 
pictures, landscapes with figures, have been called "afternoons", 
not from their subjects, but from the time spent in producing 
them. Although copying of successful motifs was very common 
in these times, maybe the high productivity of Teniers caused a 
slight stereotype in his later work. Despite this fact he has 
many followers and one of them is his favorite student Thomas 
van Apshoven (1622 and 1665). 
The second piece of art was made by Terniers pupil 
Thomas van Apshoven. He lived also in Antwerpen between 
years 1622 and 1665. In most of the cases, Thomas van 
Apshoven imitated his master’s style and his paintings can be 
easily mistaken. Also subjects of his paintings, like those of his 
master, are village festivals, interiors and genre scenes. [17]. 
Painting ,, On the Road", the second chosen piece of art, is an 
426 
oil painting on wooden board which displays classical scene of 
the Flemish countryside. 
  
Figure 2 — Explored painting by David Ternier the Younger 
,The Interieour of the Mill" as seen in daylight 
  
  
Figure 3 — Explored painting by Thomas van Apshoven “On 
the Road” as seen in daylight 
4. RESULTS 
The painting was placed on an easel in front of the 
hyperspectral sensor and illuminated as mentioned above. The 
scanning distance was set to 1,5m, so the pixel size is 0.33mm. 
The piece of art had to be treated with big care, because when 
illuminated by too powerful instruments for a long time the oil 
can be affected or even destroyed. The maximum temperature 
cannot exceed 35°C or a serious damage can occur. The 
illumination parameters were discussed with the manufacturer 
and used as mentioned above. The temperature of the painting 
was observed by a thermometer and cooling was performed by a 
fan. Ventilation of the air next to the scanned painting and the 
temperature did not exceed 30°C. The scanning speed was set to 
the minimum (10 frames/um) and the exposure time to 
maximum (40,23 um) to enable the maximum light to come to 
the detector. Scanning angle and the number of frames had to be 
set to cover the entire image. White and dark reference was 
performed by the XCAP software provided by the manufacturer. 
One detail was used for each painting. Details were 
chosen in respect to IR reflectography and the visibility of 
underdrawings. For Ternier it was the low-left corner showing 
barrels and the millers working desk (see figure 4) and for Van 
Apshoven it was the house on the horizon in the right half of the 
painting (see figure 5). The details are a RGB image synthesis 
as derived from hyperspectral image (Red A = 629,93nm; Green 
À = 529,89nm; Blue À = 449,87nm)