Why Do We Get Red Eye in Photos?

iStock/Liia Galimzianova
iStock/Liia Galimzianova

Grab a partner and look into his or her eye "“ or stare deeply into it, if appropriate "“ in a normally lit room. The quick and dirty version of how you're able to view each other is this: Light enters the eye through the cornea, the clear outer dome, and goes through the pupil. Then it travels to the cornea, which focuses it on the lens. The lens further focuses the light and spreads it across the retina. The retina receives the light and transmits signals via the optic nerve to the brain, which interprets the image.

As light enters the eye, some of gets reflected back, but the amount of light in most situations is so small, you wouldn't even know it. Right now, your partner's pupils look black and everything's normal. Now grab a camera and take a picture of your partner with the flash on. There's that demonic red eye.

Here's what happened: When you took the picture, the camera flash sent a lot of light into the eye in a very short time, the light reflected off the back of the eye and out through the pupil and, because the camera lens is close to the flash and able to capture images very quickly, it caught the light reflecting back out.

Seeing Red
So why is that light red?

Because the fundus, the interior surface of the eye that includes the retina, is loaded with melanin, a pigment that gives it a brownish-reddish color. Was that anti-climactic? Sorry.

Red eye is fairly easy to curb by using the "red eye reduction" setting found on most digital camera flashes. This setting causes the flash to go off once before the picture is taken, which causes the subject's pupils to contract and let less light in and out, and then another time to take the picture. Cameras with a flash farther away from the lens also reduce red eye because the flash hits the subject at a different angle than lens captures it.

Of course, red eye isn't all bad. The same mechanics of light reflection that ruin photos also allow doctors a non-invasive way to see inside the eye. Hermann von Helmholtz, a German physician, discovered in the 19th century that he could examine the retina by holding a bright light near his eye and shining it into patients' pupils.

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Save Up to 80 Percent on Furniture, Home Decor, and Appliances During Wayfair's Way Day 2020 Sale

Wayfair
Wayfair

From September 23 to September 24, customers can get as much as 80 percent off home decor, furniture, WFH essentials, kitchen appliances, and more during the Wayfair's Way Day 2020 sale. Additionally, when you buy a select Samsung appliance during the sale, you'll also get a $200 Wayfair gift card once the product ships. Make sure to see all that the Way Day 2020 sale has to offer. These prices won’t last long, so we've also compiled a list of the best deals for your home below.

Rugs

AllModern/Wayfair

- Mistana Hillsby Power Loom Beige Saffron/Teal Rug $49 (save $97)

- Wrought Studios Shuff Abstract Blue Area Rug $100 (save $105)

- All Modern Lydia Southwestern Cream/Charcoal Area Rug $49 (save $100)

- Union Rustic Gunter Power Loom Blue/Khaki Rug $22 (save $38)

- Willa Arlo Interiors Omri Oriental Light Gray/Ivory Area Rug $49 (save $149)

Furniture

Langley Street/Wayfair

- Alwyn Home 14-inch Medium Gel Memory Foam King Mattress $580 (save $1420)

- Andover Mills Pascal Upholstered King Bed Frame $318 (save $832)

- Sol 72 Outdoor 8-Piece Sectional Seating Group with Cushions $650 (save $1180)

- Langley Street Darren 68-Inch Tuxedo Arm Sofa $340 (save $1410)

- Three Posts Tyronza Coffee Table $147 (save $193)

Kitchen

NutriBullet/Wayfair

- Cuisinart 11-Piece Aluminum Non Stick Cookware Set $100 (save $200)

- Rachael Ray Cucina 10-Piece Non-Stick Bakeware Set $92 (save $108)

- NutriBullet Rx Smart 45-Ounce Personal Countertop Blender $124 (save $56)

- Henckels Graphite 13-Piece Knife Block Set $160 (save $340)

- DeLonghi ECP3220 15-Bar Pump Espresso Machine $120 (save $90)

Electronics

Samsung/Wayfair

- Samsung 36-Inch French Door Energy Smart Refrigerator $3600 (save $400)

- Cosmo 30-Inch Freestanding Electric Range Oven $1420 (save $1580)

- Whynter 19-Bottle Single Zone Built-In Wine Refrigerator $380 (save $232)

- bObsweep PetHair Robotic Vacuum Cleaner with Mop Attachment $226 (save $443)

- Rowenta Focus 1700 Iron with Burst of Steam $68 (save $47)

Work From Home Essentials

Foundery Select/Wayfair

- Techi Mobili Adjustable Laptop Cart $50 (save $20)

- Foundry Select Arsenault Farmhouse Desk $210 (save $190)

- Symple Stuff Clay Mesh Task Chair $128 (save $121)

- Three Posts Salina Standard Bookcase $183 (save $617)

- Lorell Hard Floor Chairmat $52 (save $39)

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Are Halloween Pumpkins Edible?

Diane Helentjaris, Unsplash
Diane Helentjaris, Unsplash

When people visit their local family-owned pumpkin patch around Halloween, they aren’t usually looking for dinner. The majority of the nearly 2 billion pounds of pumpkins cultivated in the U.S. each year are carved up instead of eaten, making the squash a unique part of the agriculture industry. For people who prefer seasonal recipes to decorations, that may raise a few questions: Are the pumpkins sold for jack-o’-lanterns different from pumpkins sold as food? And are Halloween pumpkins any good to eat?

The pumpkins available at farms and outside supermarkets during October are what most people know, but that’s just one type of pumpkin. Howden pumpkins are the most common decorative pumpkin variety. They’ve been bred specifically for carving into jack-o’-lanterns, with a symmetrical round shape, deep orange color, and sturdy stem that acts as a handle. Shoppers looking for the perfect carving pumpkin have other options as well: the Racer, Magic Wand, Zeus, Hobbit, Gold Rush, and Connecticut field pumpkin varieties are all meant to be displayed on porch steps for Halloween.

Because they’re bred to be decoration first, carving pumpkins don’t taste very good. They have walls that are thin enough to poke a cheap knife through and a texture that’s unappealing compared to the squashes consumers are used to eating. “Uncut carving pumpkins are safe to eat; however, it's not the best type to use for cooking,” Daria McKelvey, a supervisor for the Kemper Center for Home Gardening at the Missouri Botanical Garden, tells Mental Floss. “Carving pumpkins are grown for their large size, not the flavor. Their flesh can be bland and the fibers are very stringy.”

To get the best-tasting pumpkins possible this autumn, you’re better off avoiding the seasonal supermarket displays. Many pumpkin varieties are bred especially for cooking and eating. These include Sugar Pie, Kabocha, Jack-Be-Little, Ghost Rider, Hubbard, Jarrahdale, Baby Pam, and Cinderella pumpkins. You can shop for these varieties by name at local farms or in the produce section of your grocery store. They should be easy to tell apart from the carving pumpkins available for Halloween: Unlike decorative pumpkins, cooking pumpkins are small and dense. This is part of the reason they taste better. McKelvey says. “[Cooking pumpkins] are smaller, sweeter, have a thicker rind (meatier), and have less fibers, making them easier to cook with—but not so good for carving.” These pumpkins can be stuffed, blended into soup, or simply roasted.

If you do want to get some culinary use out of your carving pumpkins this Halloween, set aside the seeds when scooping out the guts. Roasted with seasonings and olive oil, seeds (or pepitas) from different pumpkin varieties become a tasty and nutritious snack. Another option is to turn the flesh of your Halloween pumpkin into purée. Adding sugar and spices and baking it into a dessert can do a lot to mask the fruit’s underwhelming flavor and consistency.

Whatever you do, make sure your pumpkin isn’t carved up already when you decide to cook with it. There are many ways to recycle your jack-o’-lanterns, but turning them into pie isn’t one of them. "If one does plan on cooking with a carving pumpkin, it should be intact,” McKelvey says. “Never use one that's been carved into a jack-o'-lantern, otherwise you could be dealing with bacteria, dirt and dust, and other little critters.”