In hydrazine-nucleated infectious development, one of the practical problems has been black spots (BS). In this paper, we describe BS morphologically, and explain two different means for restraining BS. One of them is an anion charge barrier, formed by adsorption of some kind of dyes on AgX. The other is control means of timing between fogging development and following infections development by organic acid polymer. It is also suggested that the active species in the infectious development has anion charge character and some side reactions of oxidized developer and active species play significant role.