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figuration of the surface. Fig. 4 shows the contourlines of the same
Kodak plate. The contour interval is 0,01 mm. The mean error of an
elevation read from the contour map is 0,0015 mm.
Three Kodak and three Uford glass plates both the emulsion side
and the glass side were examined by this method. Moreover two
Ilford non-émulsioned plates were measured. It was concluded that
the plates are approximately parallel but somewhat curved, though the
curvature does not generally exceed 0,2 mm.
Fig 4-
