When a toy agent showed Seven Footer Press founders David Gomberg and Justin Heimberg technology that had previously been used for security purposes to make hidden images appear, it wasn’t immediately clear that it could work for books. But when the word “ghosts” came up later in the conversation, Heimberg says that they started to see the possibilities for using the MagicView lens, a rectangular Plexiglas decoder with a right and wrong side, for two series of books, both involving hidden spirits. “It was a really interesting creative challenge,” he adds. “You’re writing a story, but you’re writing for technology.”

A year and a half later, after that initial meeting and a second one with the Chinese inventor at his offices in a back alley of Hong Kong, Heimberg’s large format “Where’s Waldo” style book, The Spirit Glass (Oct)., designed by Junko Muyakoshi, is just out. Young readers can use the lens to scan colorful page spreads in search of buried pictures and text about ghosts and UFOs. The search will continue online with a contest that incorporates clues found in the book at the Spirit Glass Web site, which will be posted later this week. The winner will have his or her likeness appear as a ghostly image in the second book, due out for Halloween 2012, Beyond the Spirit Glass.

In addition, Seven Footer just released the first in a series of middle-grade paranormals by Heimberg, chief creative officer of Seven Footer, Ghosts of Rockville: Search for the Dominion Glass (Sept.). Heimberg describes the five-part series as a cross between 39 Clues and Harry Potter. It relies on the same MagicView technology as The Spirit Glass, but the included lens is thinner and more flexible so that it can be turned at more angles to offer clues about each character in the book. The novel is a young reader’s top pick in scary stories at Barnes & Noble.

Even though Heimberg has written numerous books and screenplays, he says, “these books are special to me. There’s a real sense of wonder the first time kids see it, which is great.” It shows that print books can still make children get excited, plus Heimberg believes that they will appeal to reluctant readers, especially The Spirit Glass.

Both books were printed in China under the supervision of the inventor, “Alex,” and are being launched in the U.S. with a 20,000-copy first printing. Seven Footer offered samplers for booksellers and librarians at BEA and ALA so that they could better understand the technology involved. The pages look just like regular print book pages; it’s just that additional copy and images appear when the lens is used with them. Lenses come in a sealed envelope in the front of each book. If the are lost, Seven Footer will replace them and is looking at ways to sell them separately.

Ghosts of Rockville: Search for the Dominion Glass by Justin Heimberg. Seven Footer Kids (PGW, dist.), $16.95 Sept. ISBN 978-1-934734-48-3

The Spirit Glass: A Book of Magically Hidden Images by Justin Heimberg. Seven Footer (PGW, dist.), $16.95 Oct. ISBN 978-1-934734-49-0