Abstract: This paper deals with kinetics of hydrazine-promoted infectious development by meansof measurements and calculations of development rate and activation energy,mechanism isdiscussed at the same time. The experimental results are as follows:direct development withlow activation energy dominates early stage of development;the later stage is fogging nucleation with high activation energy;there is no development of fogging nucleation for low exposured latent nucleus,but with higher activation energy;the results of super high contrastand short toe are the competition between development acceleration and retardation.

Key words: super-high contrast, development kinetics, activation energy, hydrazineinfectious development