The relationship between the structures of acyl groups in acylhydrazides and hotographic performance was systematically studied to find new nucleating agents used for a low-pH ultra-high contrast graphic arts system. A strong electron-withdrawing acyl group was necessary for low-pH nucleation activity, but this feature mostly resulted in the decrease of storage stability. Therefore some novel acyl groups incorporating intramolecular hydrogen bonding were designed and synthesized. Among them the 2-carboxytetrafluoropropanoyl group was found to be the best acyl group to satisfy the conflicting demands for use in scanner/camera films. As for contact work films, a much more reactive acyl group in an adsorptive nucleating agent was required to overcome low sensitivity of the emulsion toward nucleation. We found that steric compactness and moderate electron deficiency in acyl groups were essential to realize the highest reactivity. Based upon kinetic studies of acylhydrazides in processing solutions, ucleation activity in acylhydrazides was rationally explained by the kinetic properties and the hydrophilicity of the acyl groups.