look at this great book i got at the 826 valencia pirate store! it’s a reissue of a book first published in 1863 called spectropia or surprising spectral illusions. the book is full of colored figures against a white background.
if you stare hard at the images then look away from the page, your eyes will continue to see a ghostly representation of the figure. it’s an old optical trick, a trick that the book attempts to explain in great scientific detail. in fact, the primary purpose of the book is to disprove the existence of phantoms by allowing the reader to purposely create their own.
the author writes, “one thing we hope in some measure to further in the following pages, is the extinction of the superstitious belief that apparitions are actual spirits, by showing some of the many ways in which our senses may be deceived, and that, in fact, no so-called ghost has ever appeared, without its being referable either to mental or physiological deception.”