An article, which I started writing as a blog entry in 2009 (!), was published last year: “Cancelled Errata in John Buncle, Junior, Gentleman,” Script and Print, vol.38, no.2 (June 2014): 115–21 (here). The article describes a rather unusual problem confronting the bibliographer wishing to describe the collation of the first few gatherings of John Buncle, Junior, Gentleman (1776).
My article considered the problem in relation to the difficulty of accounting for all pages in the pagination and collation formula in such a situation (a single leaf having, in effect, four pages: two glued face-to-face). I invited comment and was delighted to receive careful consideration from a number of senior scholars in the field (which will be published soon), who concluded (among other things) that this was a rare example of a full-page slip-cancel.
Shef Rogers, the editor of Script and Print, has just directed my attention to another example of a full-page slip-cancel Format: an example of common duodecimo with an uncommon frontispiece: in Plays written by Mr John Gay (London: W. Strahan, T. Lowndes, 1772) [ESTC: t13746 (listing 57 copies here); reissued in 1772 as t13741 (listing 6 copies here) and in 1795 as t13742 (listing 10 copies here)].
E. Kenneth Giese (from the Special Collections & Archives Department of Goucher College in Baltimore, Maryland) explains that, in this book, you can see Peter the Great faintly showing through the frontispiece depicting John Gay (A1v):
One can also see and feel that the leaf with the frontispiece actually consists of two identical leaves of paper fused together, but it is impossible to see how the one was overlain atop the other […] When viewed normally the engraving behind Mr Gay is discernable only as a faint shadow embedded within the paper. At first glance I thought it had been offset from another sheet. Held up to direct light this shadow engraving can easily be identified as "Peter the Great / Czar of Moscovy"—a copper plate line engraving by John Hall (1739-1797). I suspect that the full sheet was first printed letterpress; that the wrong copperplate engraving was used when the sheet went through the rolling press, and that a leaf with the correct engraving—"the Cancellans", was pasted over "the Cancellandum" […] Not only are the chain lines seamlessly matched, so too are the laid lines! Because the fusion is perfect, the effect is magical.
Giese asks if "this copy-specific attribute" is unique. With 73 copies on ESTC, and a number available for sale online, it shouldn't be too difficult to find out. And, since there are three copies in Oz, one in the Parliamentary library here in Melbourne, I plan on answering out Giese's question. Stay tuned!
BTW: Copies that are available online, like this one from New York Public Library, and this one from the British Library, do not show the "faint shadow embedded within the paper," but that is because of the way in which the contrast has been fiddled with to make the ink stand out from the discoloured, off-white paper (which is intended to erase such faint shadows).