Last Halloween season we took a stroll through our special collections pumpkin patch. Today, we’re looking for ghosts! And we found them in this amazing optical illusion book titled Spectropia; or, Surprising Spectral Illusions. Showing ghosts everywhere, and of any color. Published by J.H. Brown in London in 1864, the book teaches the concept of “the persistency of impressions, and the production of complementary colours on, the retina.”
The illusion is very simple. In the image above, stare at the small black dot by the ghost’s neck for 20-30 seconds. Then look away at a white wall or ceiling. Her ghostly image will appear in your vision, except in different colors (in this case green wreath, blue ghost)!
Scientifically speaking, this is called an afterimage. The color receptors in your eyes work in pairs (red/green, blue/yellow, etc.). When you stare at the drawing and one color fatigues your receptors, the other receptor will step in and dominate for a bit.
The book has a very lengthy description of this concept, as well as viewing instructions that include having the “gaslight turned low.”
Spectropia also has a disclaimer at the beginning: “As an apology for the apparent disregard of taste and fine art in the plates, such figures are selected as best serve the purpose for which they are intended.”
I wish they might have reprinted the disclaimer before THIS image, which honestly is going to haunt me clear through December:
The book concludes with a grand finale image that is not a ghost, but a rainbow! Definitely try this one, because it is so cool to see the colors flip in the afterimage!
Looking more more optical spooky fun? Try making our tabletop Pepper’s Ghost illusion!
Images from Spectropia; or, Surprising Spectral Illusions. Showing ghosts everywhere, and of any color. J.H. Brown, London. Griffith and Farran.1864. Cotsen Children’s Library, Department of Special Collections, Princeton University Library.
The churchyard is part of the Old Dutch Church of Sleepy Hollow, which was constructed in the 17th century. Featured in Irving’s short story, it’s one of the of the oldest churches in New York State.
From the church, we headed down to the FAMOUS BRIDGE. Which, as it turns out, is the “is the most popular destination in Sleepy Hollow that doesn’t exist.” Because the simple 1700s wooden bridge that inspired Irving has long since disintegrated (you can read a little more bridge history 
The bridge is located in a pretty major intersection with a gas station nearby. So it’s almost a blink-and-you’ll-miss-it historical literary moment. Here’s the bridge as it stands today…
Not far from the bridge is the town’s official statue, depicting Ichabod’s fatal race home. This was a bit of a surprise too. I expected something more traditional. But I like the metal layers on this interpretation – they’re almost like a paper cut silhouettes. Unveiled Halloween 2006, the statue was designed by artist 
We also got an unexpected surprise at the nearby Philipse Manor train station, which operates on the Metro-North Railroad’s Hudson Line. The station’s pedestrian bridge had really cool stained glass windows…
And check out the VIEW of the Hudson River on the other side!
At this point, we were getting hungry, so we headed over to Tarrytown for some bites. Main Street was charming, walk-able, and there were plenty of eateries to chose from.
One other building of note is the historic Tarrytown Music Hall, a 136 year-old 
The sun was starting to set as we headed back to New Jersey with haunted places still on our minds. This Halloween, when I revisit Irving’s tale, I’ll actually be able to say that I’ve walked through the cemetery, stood next to the church, and crossed the bridge! How awesome is that?