Optical Illusions and Special Effects

"Potato Chips, 1¢, Packed for Interstate Biscuit Co., Bronx, New York. Net weight one-quarter ounce or over. Before eating. After eating." For a similar item, see I Eat at the Royal Coffee Shoppe / I Don't :

"I eat at the Royal Coffee Shoppe, 919 Orange St., Wilmington, Del." "I don't." See also Before Eating Potato Chips / After Eating Potato Chips :

A novelty advertising card for country musician Hank Keene's radio show that gives instructions for experiencing an afterimage of Keene's silhouette. Magic Picture - Hank Keene Keep your eyes on the white spots on the face and count slowly up to fifty. Then turn away from the picture and look at one spot on the ceiling. The picture will then appear before your eyes on the ceiling. If you keep your eyes on one spot on the ceiling the picture will appear and disappear several times. Amuse your friends by showing them this magic picture. Tune in on Hank Keene and his Radio Gang on station WHAS, Louisville, Kentucky, every morning except Sunday from 6:00 to 6:30 Central Standard Time.

See also a detail showing a close-up of the flag image (below). Lasting Impressions Stare at this flag, dear friend, Then look away, The image still stands by you. If next Sunday, you'll attend Our Rally Day, Like impressions will then ensue. Directions. Take card in both hands, look steadily at small diamond shaped speck on flag, try not to blink, and count to 40 slow, then look up at sky or a light wall and picture will appear greatly enlarged. Keep looking at one spot for 10 seconds. Result--the actual picture will appear and disappear several times.

See also the full version of this postcard (below). Directions. Take card in both hands, look steadily at small diamond shaped speck on flag, try not to blink, and count to 40 slow, then look up at sky or a light wall and picture will appear greatly enlarged. Keep looking at one spot for 10 seconds. Result--the actual picture will appear and disappear several times.

As Wikipedia explains, " Spook Hill is a gravity hill (an optical illusion where cars appear to roll up the spooky hill) in Lake Wales, Florida." "Spook Hill, Lake Wales, Fla. It's weird! Fantastic! Stop on line. Release brakes. Watch for cars when you roll back. Prather's Laundry & Dry Cleaners. Watch for Prather's White Trucks." Description printed on the back of this postcard: "A few blocks from the heart of Lake Wales is that mystifying and fascinating phenomenon, Spook Hill. Here playful ghosts apparently seize your car and in defiance of the laws of gravity and your previous experience in such matters, roll your vehicle gently backward uphill, while they chortle in unholy glee at your mystification. Handwritten message: "Stayed here last night and went to Bok tower but it was so foggy. It is sunny now about 75 degrees. By the time this card is written we'll be in Miami. Torrey. Erna." No address, stamp, or postmark. Todd Franklin (Neato Coolville) also has a copy of this over on Flickr: Spook Hill Postcard .

A novelty card with instructions for experiencing a ghostly afterimage of a "skeleton on the wall." For a vertical view of the skeleton, see a rotated version of the card (below). The other side contains a list of Whip and Fan Flirtations (below). For other cards that use the afterimage effect, see Hank Keene's Magic Picture and Lasting Impressions . The Ghost Card, or the Skeleton on the Wall Directions . Select a small black spot on a white wall, or white sheet—a spot that you can find again at once; let this spot be in a deep shadow . Then holding the card in the hand gaze intently on the eye of the skeleton, while the light falls brightly on the card. Keep the eyes on this one spot without moving or winking for two minutes; then suddenly look at the spot on the wall for two minutes. Keep the eye very steady in both cases, you will then see distinctly the same skeleton on the wall. For a parlor entertainment this is one of the grandest things ever witnessed.

For more information, see The Ghost Card, or the Skeleton on the Wall (below). For the back of the card, see Whip and Fan Flirtations (below).

"First Pick. O. L. Schwencke, lith., N.Y." A cigar box label printed by O. L. Schwencke. Notice how a box featuring this label appears within the design of the label itself. This recursive picture-within-a-picture is called the Droste effect , which is named after the Droste cacao tin that featured an illustration of a nun holding the tin.