Hello? Hello!

Today’s post will cause you to stare at blank walls in a darkened room. For that, I am sorry/you’re welcome.

In December 1863, a Brighton man named J.H. Brown published Spectropia, a 27-page book that lays out how readers can create ghostly afterimages when they stare at one of the book’s 16 illustrations of “spectres” for 20 seconds and then look at a white, blank wall.

Brown wanted Spectropia to act as a bulwark against the rising tide of Spiritualism, a movement whose followers believed they could commune with the dead via séances conducted by so-called mediums.

(The book, in fact, holds a mirror to Sir William Crookes’s “scientific séances,” which I covered in an earlier post. But where Crookes’s experiments were clouded by his untested confidence in the galvanometer and his arrogance that no woman could outwit him, Brown relied on studied scientific principles to make his anti-Spiritualist case.)

I couldn’t find much about Brown, other than the fact he was from Brighton. His anti-Spiritualist stance, however, is unambiguous. In the second part of the book, where he explains why we see those afterimages, he writes:

“It is a curious fact that, in this age of scientific research, the absurd follies of spiritualism should find an increase of supporters; but mental epidemics seem at certain seasons to affect our minds, and one of the oldest of these moral afflictions — witchcraft — is once more prevalent in this nineteenth century, under the contemptible forms of spirit-rapping and table-turning.”

Brown’s effort to debunk Spiritualism echoed some magicians’ efforts around this time. In 1865, the 26-year-old John Nevil Maskelyne saw the Davenport Brothers in England and stood up in the middle of the performance to claim he knew the non-supernatural methods the duo used. He then built a career out of performing a similar act himself —similar illusions, but no otherworldly assistance.

“This book, very strangely, is like the optical illusion version of that,” explained illusion designer and historian Jim Steinmeyer, whose book Hiding the Elephant touches on this topic. “It makes this weird circular argument: Is it enough to say, I don't use supernatural powers and I do the same thing, therefore it's fake?”

For some (many?), it is not. And Spectropia is perhaps even less compelling than similar efforts, because as Steinmeyer pointed out, Brown is “a little desperate with what he’s doing, because, of course, he's not actually saying, ‘This is what's happening in a séance room.’”

Spectropia’s publisher didn’t seem interested in Brown’s anti-Spiritualist plea either. The book was marketed as a fun parlor game, a way for folks to stave off boredom for an evening. “Ghosts Everywhere!” one ad begins, promising that purchasers will conjure up “Ghosts of all sizes, all styles, all colors, at sixty second notice!!!”

The “toy-book,” as Spectropia was also described, proved popular, first in London and Sydney and then in the United States, where it sold for $1 (around $21 today). While one reviewer heralded the work as an “elegant volume [that] may familiarize even the thoughtless with optical laws, and thus abate the tendency to superstitious impressions,” Spectropia’s success as an anti-Spiritualist tool is difficult to measure. Indeed, another critic dismissed the publication as a “philosophical plaything intended to amuse children and youth.”

Brown implicitly acknowledged that many readers would open Spectropia and skip straight to the directions for creating afterimages.

(And let’s be honest, some Tube Talk readers might want to do the same. If that’s you, head to the end of this post for more images to stare at.)

But for “those who may wish to know more,” he included a “brief and popular, as well as a scientific, description of the manner in which the spectres are produced.”

In that section, Brown correctly described why, if a person stared at one of the book’s images under a strong light source for about 20 seconds and then gazed at a blank wall in a darkened room, a version of that image in inverted colors appeared.

Today, psychologists know this phenomenon occurs because the color-sensing cells, or cones, in humans’ retinas lose sensitivity to a particular hue after prolonged exposure.

Let’s say you stare at the above illustration from Spectropia for about half a minute. If you then look at a white wall, you’ll briefly see a green version of that wizened individual about to hit that poor dog, even though the original is entirely red.

The color flips because your retinas’ ability to perceive red is temporarily fatigued. Since white light contains all color wavelengths, you’ll still see the primary colors of blue and yellow, which, when mixed together, yield red’s complementary color, green. In addition to reversing the color of an image, afterimages can convince your brain that an object has changed in shape or size. All told, Brown argued in Spectropia, “There can be little doubt but that many of the reputed ghosts originate in this manner.”

Brown wasn’t successful in turning the tide against Spiritualism — it was too easy for those who believed to say that this scientific phenomenon existed, but that ghosts are still real. Brown did, however, entertain hundreds, if not thousands, of Victorian families. And if you stared at a blank white wall at any point while reading this, perhaps he also entertained you.

Part of this post originally appeared in my article for smithsonianmag.com, published on October 29, 2024.

Here’s one below, and here are others you can see by clicking these links:

That red wizard(?) and his blue dog

A ghoulish portrait

A pointing wraith

A frog witch