Colour bias is one major cause of poor colour composite images. To eliminate this, the three bands used for colour composition must have an equal value range and mean. The balance contrast enhancement technique (BCET) is a simple solution for this problem. Using a parabolic or cubic function defined by three coefficients, BCET can stretch (or compress) images exactly to a value range and mean given by a user without changing the basic shapes of the image histograms. The FORTRAN program of BCET using parabolic (BCETP) and cubic (BCETC) functions have been developed. As colour bias is completely avoided and the full value range of the display system is properly used, high-quality colour composites as well as black and white single-band images are produced by BCET.