... and one of the most interesting & rewarding aspects of designing this piece.
The colour used for the 'hidden' pirate head needed to be unobtrusive enough to allow the image to, perhaps, be overlooked at first glance. But not so subdued that I'd be the only one to ever know that it was there.
While pouring through my embroidery threads and trying to decide which colour to stitch the 'hidden' pirate head, I re-discovered my spool of Kreinik Glow-in-the-Dark thread. Hmm, a treasure map that not only points out the location of buried treasure, but also hides a pirate (who only becomes visible when the lights go out)... what fun!
Although I eventually decided to stitch the original model using regular threads, in order to show how the piece would look without this enhancement, the substitution is quite simple. Just replace the DMC 3013, used to stitch the pirate head, with your choice of Kreinik Glow-in-the-Dark thread.
PLEASE CLICK ON THE SECOND PICTURE FOR A LARGER VIEW
I would suggest using the #4 Very Fine Braid for the Glow-in-the-Dark option and would just like to mention that Kreinik 052F (Grapefruit) shines brightest. In order to increase the visibility of the pirate outline in areas that are defined by a single line of stitching (around his beard, hat, etc.) you may prefer to stitch those areas with a double-strand of this thread.