A systematic approach is proposed for developing tissue mimicking materials. Speed of sound and the attenuation coefficient slope are combined in a so-called c-α chart. The procedure described was used to produce the tissue mimicking materials with a speed of sound of 1540±6 m/s and the attenuation slopes of 0.3 dB/cm.MHz and 0.45 dB/cm.MHz with very low scatter as required for Thin Film Phantom. The tissue mimicking materials were applied to a TFP (Thin Film Phantom) system to get images of a character set made of digital scatterers deposited on a plastic substrate.