Cotsen Ghosties

book cover 3Last 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.

Book Title Mash Up

Does your taste in books vary wildly? No problem, just combine them! We designed this book title mashup activity as an ice breaker for Cotsen Critix, our literary society for kids ages 9-12. It was inspired by the hilarious Very Condensed Book postcards designed by Hilary Brown Greetings.

The kids had a fantastic timer recounting titles and mixing them up, as well as talking to each other about the books they love. Here’s our favorite dozen…

Are you my Mother, Harry Potter?
The Twilight Games
We the Big Idea Math People
Beauty and the Deathly Hallows
Warriors on the Prairie
Snow White and the Titan’s Curse
Under the Holes
A Wind in the Wardrobe
Go BFG Go!
Where the Sidewalk Ends Wild Things Are
If You Give a Mouse a Chocolate Factory
The Confessions of Charlotte’s Web

Wait ‘Til the Midnight Hour

It may be midnight, but there’s always time to explore this awesome little 2D library, and possibly discover a hidden letter or two!

We recommend reading The Midnight Library by Kazuno Kohara (Roaring Book Press, 2014, read here by the Ingleside Public Library). Welcome to a very special library: it’s only open from midnight to dawn! The little librarian, along with her three assistant owls, work together in the dark and help the forest animals find a place to play music, read the perfect story time book, and even sign up for a library card!

You’ll need:

  • 1 midnight library template, printed on 8.5″ x 11″ paper
  • 1 clear piece of 8.5″ x 11″ plastic (more on this below!)
  • Sharpie permanent marker
  • 1 piece of black construction paper
  • One flashlight template, printed on 8.5″ x 11″ card stock
  • Scissors for construction
  • Markers for decorating
  • Optional: fine tip dry erase marker

Begin by printing the midnight library template. Then, place a piece of plastic on top of the template and trace it using a Sharpie permanent marker. We used archival mylar, but you can also use the clear cellophane rolls you find in the gift basket section of your local craft store!

Replace the paper library template with a piece of black construction paper. Tape the corners of the black construction paper to a tabletop, then tape the corners of the plastic to the tabletop as well. Really to explore the library? Slide the flashlight’s light beam between the construction paper and plastic to “illuminate” the scene!

Want to take the project up a notch? Use a fine tip dry erase marker on the plastic to “hide” letters in the library, and ask your young readers to locate them. Once all the letters have been discovered, you can erase them and start anew! You can make the letters random, or ask kids to string together various words and/or messages. For example, I’ve hidden the word “hello” on this shelf…can you find it?