Abstract: Different from conventional development, Lith development proceeds with parallel pattern of grain population reduction over a wider range of exposure. If sequential pattern of grain reduction occurs, the density growth only gives information about the distribution of development induction period among grains. Only when parallel pattern of grain population reduction occurs, the density growth gives information about the rate at which a single grain develops. In other words, only when all the developable grains in emulsion layer develop in parallel, the whole layer will have the same developme nt kinetics as that of a single grain and this makes the whole process autocatalytic in nature. So the autocatalytic nature of Lith development can be attributed to the parallel pattern of grain population reduction.

Key words: Lith effect, development induction period, parallel development