<p>A photosensitive material containing a hydrophilic pigment is exposed to light to form a pigment pattern defining a particular image. The photosensitive material is brought into intimate contact with an image receiving material having a pigment fixing layer. The mutually contacting materials are heated so that the pigment may be transferred from the photosensitive material to the pigment fixing layer. A pigment diffusion assistant, is supplied to an area between the mutually contacting materials before they are heated for pigment transfer. The diffusion assistant spreads along a line along which the two materials are in contact with each other and promotes the transfer of the pigment.</p>