My 'A House in the Woods' concertina book is in the Inspired by... show at Morley College, curated by the V&A. It runs until 17 June - more info here: http://www.inspired.by/
(click on the pictures to enlarge them)
...and this is the process. I painted with Camp (chicory coffee) solution on the etching plate (it acts as a resist), then covered it in straw hat varnish, submerged the plate in warm water and waited for it to lift. Several layers of Aquatint followed. The image needed more definition so I added more Aquatint later and scraped some of it back (see proofs above).