Wolfram's right, the stain has be proportional to the density of the silver image, otherwise what's the point?(posted 8824 days ago)You can use a re-halogenating bleach, such as is used in certain intensifying processes, and then re-develop in Pyro to get the staining effect, but you would probably lose most of the characteristic of the original developer. The Pyro stain tends to spread out in the emulsion, so I don't think a true acutance effect is possible.