Digital BW, The Print

Does anyone know of a coating to apply to Hahnemuhle Photo Rag dual sided 308 paper 
that will actually seal the blacks from transfering on to facing pages. I have done a number 
of books for graduating photo and design students with this wonderful paper and have 
always sprayed it with Premier Art and Lyson Printguard in two heavy coats. However, we 
are still seeing black ink transfer to facing pages within a short period of time.

Now I have a client who wants to produce very high-end wedding portrait books, leather 
bound with a fine rag paper but we are facing this same issue of ink transfer. We don't 
have to use rag paper but I would prefer to.

So, is there a coating, laquer, or something that I could use to stop this from happening? It 
seems to me that I remember Paul Roark talking about some sealant he was using. Any 
other ideas?

This paper ideally would be a relatively heavy fine rag media. I know Somerset and 
Concorde Rag have the coating more down in the paper, but they aren't dual sided and 
would probably transfer blacks anyway with the sprays that I've been using.

Any suggestions would be helpful,

John