Weissenberg Camera and Moving Film Technique

It should be mentioned here that the reciprocal lattice which is three dimension cannot be recorded without any ambiguity on a two-dimensional film and so, the rotational method discussed before is not sufficient to record the diffraction spots with their three hkl indices known. Therefore, the rotational method cannot give any satisfactory information about the Space Group from the rule of systematic absences. Moreover, there is every chance of coincidence of the diffraction from one hkl and its hkl counterpart and so, they hardly can be read separately. Therefore, it becomes necessary to move the film along with the rotation of the crystal to record one reciprocal lattice net lying on a plane. 

knowing such hkl values of the spots of the X-ray diffraction photographs which are undistorted record of the reciprocal lattice, the Space Group and also the crystal structure can be determined. It may be once again stated here that by Space Group, we should mean the spatial symmetries which 

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