PURPOSE: To prepare a decorative material having a cubic, dynamic feeling of natural wood by forming on a base sheet at least a printed grain pattern and an embossed pattern consisting of a group of wave curves which is running in the same direction as the printed grain pattern.
CONSTITUTION: A group of wave lines is represented by an assembly of curves in which series of curve units including sine curves, cycloidal curves, and arc curves are arranged in parallel. A group of curves is used which is arranged into a pattern as an enciphered group of curves and can be drawn with computer equipment such as an x-y plotter. The group of wave curves, prepared in this manner, is used for an original plate, and an embossed plate is prepared by the usual method in which, for example, a copper plate is eroded by a photo- etching process. Using the embossed plate, a continuous embossed pattern consisting of a group of wave curves is formed on the base sheet. In the processing of the embossed pattern, the direction in which the grain in the printed grain pattern runs is arranged nearly in parallel with the direction in which a group of wave curves runs.