Abstract
Tn a sulpllur-plus-gold-sellsitized AgBr emliision exposed at higll intellsity, most sllb-image centres contain gold. Tile celltres are detected by normal development after tile exposed grair,s are latensified with low-intensity light. A dilute solution of KCN is used as a bath to remove gold from the centres. It is suggested that the important two-atom centre formed by high-i,ltel1sity exposure of this emulsion is AgAu, and lI,at the clwracteristics of this centre are important in determillillg the high efficiency with which cenltres form.