The transparencies of an original for the primary colors are measured at a series of discrete points. The transparency values are processed to adjust for the characteristics of the copy material and the characteristics of the light source used to form an image of the original on the copy material. The light source is a cathode ray tube which generates an image forming beam having a Gaussian intensity distribution with a maximum at the longitudinal axis of the beam. The copy material is a hard copy material having three layers each of which is sensitized to light of a different primary color. Each layer responds to light of the corresponding color having an intensity in excess of a corresponding threshold level but exhibits no response to light having an intensity below this level. An image of the original is formed on the copy material point-by-point using the image forming beam from the cathode ray tube. The size of each image point depends upon the intensity of the beam relative to the threshold levels. By regulating the intensity of the beam on the basis of the adjusted transparency values of the original, the sizes of the image points are such that the tones of the image correspond to those of the original.