The induction mechanisms of planar arrangements in cholesteric liquid crystals (CLC) which showed selective reflections of visible light were investigated by measuring the selective reflectivity and FTIR peak intensity of $C{equiv}N$ stretching band. Although the planar arrangement of CLC was not as perfectly induced as the cases prepared with using alignment layers, it could be also induced by stretching polymer substrate or by applying shear forces. The planar arrangements were induced by forming CLC helical structures on top of liquid crystal molecules which were in contact with the substrate and oriented all in the same direction.