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2. 3 Photographie handling of original products 
During the period of this investigation, close collaboration was established with the 
Photography Dept, of ITC, which held the burden of handling and enhancing the 
original products as received from NASA. The advantage of having at hand an ef 
ficient and able photo-laboratory was demonstrated beyond all doubt. The possibili 
ties of feedback between the photo-laboratory and the investigators facilitated the 
tasks of both considerably. The photographic work was divided into three catego 
ries: 
a) Improvement of contrast and density in the black and white products. This was 
considered necessary because of the difference of contrast and density in the 
imagery corresponding with the four diffèrent MSS bands. Band 4 was especially 
poor compared with the other bands. The positives were generally too dark with 
a limited contrast. This had two consequences. Firstly, the black and white 
positive of this band was so poor that it had a very limited value for interpre 
tation. Secondly, when used to produce a colour image together with other 
bands, band 4 did not contribute enough information to the resulting colour 
image, so that the latter contained almost exclusively the information of the 
other bands. An improvement was possible using photographic techniques such 
as controlled development, dodging, etc. The final results improved the origi 
nal negatives considerably. 
b) Double printing of two bands with on- or off-registration. 
In order to facilitate the comparison of the appearances of a certain unit, 
several two-band paper prints were prepared using a "sandwich" of a negative 
and a positive of different bands as a negative. This method worked well enough 
and provided a quick solution to the problem of determining differences over a 
large area, although a point by point examination was preferable for more de 
tailed work. 
Relief enhancement was obtained by off registration (0. 2 - 0. 3 mm) printing of 
a "sandwich" of two different bands or using the negative and positive of the 
same band. Some linear features (fault lines, drainage) became much clearer 
than on the initial imagery. A further advantage of the above prints was the 
anaglyphic appearance of the final print. The effect of the displacement com 
bined with the appearance of dark tones (lakes and rivers) as lower areas and 
light grey tones (hill tops) as higher areas gave a substitute for stereoscopy 
and in some cases facilitated the interpretation. 
c) Colour composite printing. 
A series of colour products in the form of paperprints and diapositives were 
produced by the photography Department of ITC. These were obtained by pro 
jecting black and white transparencies of two or three different bands through