Monday, March 25, 2013


The Legend of the Easter Egg

I found my little Easter booklet given to me by my grandmother in the 1950s. The following is the Ukranian legend.

"One day a poor peddler went to the marketplace to sell a basket of eggs. He came upon a crowd mocking a man who staggered with a heavy cross on which he was about to be crucified.

The peddler ran to his aid, leaving his basket by the roadside. When he returned, he found the eggs transformed into exquisite designs of bright colors.

The man was Christ; the peddler, Simon."

Sunday, March 24, 2013

The Legend of the Iris

The Legend of the Iris

     "Thomas, beloved apostle of Jesus, was grief stricken by the crucifixion of his Master. And as much as he wanted to believe in a resurrection, his mind simply could not grasp such a miracle.
     Three days after the Master's death, Thomas was walking a familiar path to Galilee when he noticed a lovely flower growing by the wayside. Only weeks before, the plant had been withered and brown, dead to all appearances.
     'It has been reborn,' thought Thomas. 'Could this be an example of resurrection as our Lord explained it to us?'
     His heart bursting with new hope, Thomas hurried to the place where the apostles were gathered. And there he found his Lord, risen from the dead as He had promised."

See John 20:19-29 for the rest of the story.

"Iris" painted by Vincent van Gogh

Thursday, March 21, 2013

Red as an Aphrodisiac

The color you need to wear on your dating profile.

Research suggests that the woman wearing red is likely to attract more sexual attention than her otherwise identical counterparts.
Research suggests that the woman wearing red is likely to attract more sexual attention than her otherwise identical counterparts
Photos courtesy of American Apparel
Let’s imagine for a minute that six identical 23-year-old female sextuplets were born and raised in a secluded U.S. town. The town is too small to provide six eligible male bachelors, so the women post their pictures on a nationwide online dating site. Their pictures are almost identical, but the women distinguish themselves by wearing six different-colored plain T-shirts. Based on their profile pictures alone, you might expect them to attract similar levels of interest—but you’d be profoundly wrong.       
Humans had been honing the practice of courtship for millennia when Gary Kremen threw a wrench in the works.  Kremen launched, the world’s first online dating site, in January 1995.  Match democratized the dating world, giving the shy, nervous, and squeaky-voiced relationship-seekers a chance to shine in a game once monopolized by alpha males and bar room Casanovas. In contrast to the fast-paced world of face-to-face dating, online daters have plenty of time to choose flattering photos, hone their profiles, and craft personal messages.  But while the playing field is more level than it used to be, it still involves mastering unspoken rules that give some people advantages over others.

According to Christian Rudder ofOkTrends, OkCupid’s now defunct research site, 32 percent of all first-time messages attract a reply. In other words, two of every three initial messages are met with silence. But response rates vary widely depending on a few critical word choices.  Netspeak is usually disastrous (the response rate for messages featuring “ur,” “r,” and “u” is less than 10 percent), while almost 50 percent of all personalized messages that feature “you mention” or “noticed that” win a reply. The aimless, noncommittal “hi” earns a response 23 percent of the time, while messages featuring the direct question “how’s it going?” attract a 53 percent reply rate. Of course the people who craft these various introductory messages differ on other dimensions as well, but these figures show just how fickle online dating outcomes can be.
But while people labor over their personal messages, another critical factor slips by unnoticed.  Several years ago, Andrew Elliot, a professor at the University of Rochester, and his colleagues began by asking heterosexual male undergraduates to spend five seconds looking at the photo of a young female stranger, and to rate her attractiveness on a scale ranging from 1 (not at all attractive) to 9 (extremely attractive). All of the undergrads saw the same woman wearing the same clothes—but the experimenters randomly changed the color of the thick border that framed the photo, alternating among white, red, blue, and green.
Psychologists know some things about color: Blue is the most popular color in the world, black is associated with elegance, wealthpower, and strength, green soothes and calms, and red is the color of love and romance. But Elliot and his colleagues were trying to figure out whether color can actually change a person’s appeal.
Across five experiments, the results were always the same. The male undergrads who rated the photo bordered in red, found the woman more attractive, were more interested in asking her on a date, and willing to spend more money during the date. The researchers were also careful to show that the effect was specifically tied to sexual interest. They showed, for example, that when heterosexual women rated the attractiveness of the same female stranger, they weren’t swayed by the border’s color. In addition, men didn’t believe the red-bordered woman was more likable, kind, or intelligent—only that she was more attractive and sexually appealing.  
Women are more likely to attract sexual attention when they appear in a photo bordered by the color red.
Women are more likely to attract sexual attention when they appear in a photo bordered by the color red
Photos courtesy of American Apparel
Nicolas Gueguen, a psychologist at the University of Southern Brittany in north-eastern France, wasn’t satisfied with lab studies alone, so he moved his investigation to the field, to see if these lab results also applied in the real world. Gueguen hired five brunettes between the ages of 19 and 22 to pose as hitchhikers. The women wore jeans, sneakers, and a figure-hugging plain-colored T-shirt—much like the shirt worn by the fictional sextuplets. Taking turns on a string of bright early summer days, each one stood by the roadside near a famous peninsula in Brittany, and held out her thumb to show she was trying to hitch a ride. When 80 cars passed by, the woman retreated and changed her T-shirt, randomly choosing from a menu of black, white, red, yellow, blue, and green. (Two observers monitored the situation out of sight to ensure that the women were safe.)
Several days and 4,800 passing motorists later, Gueguen returned to the lab. Like the women in Elliot’s study, Gueguen’s female motorists weren’t influenced by the color of the hitchhikers’ T-shirts—they were just as likely to stop when the women wore red as when they wore any of the other colors. In contrast, male motorists were far more discerning, stopping about 12 to 15 percent of the time—except when the women wore red T-shirts, when they stopped 21 percent of the time. Like the male students in Elliot’s lab study, male motorists preferred the women in red.
Two years later, Gueguen and his colleague, Céline Jacob, repeated the experimentamong online daters. During a nine month period, 64 women who were looking to meet a man agreed to post their pictures on an online dating website. Gueguen and Jacob used digital software to create six photos for each woman, identical except for the color of their T-shirts.  Every two weeks they rotated the image on the website, and asked the women to count how many men contacted them. As with the artificial sextuplet thought experiment, six identical-looking women (apart from the color of their T-shirts) were effectively competing for the attention of thousands of male suitors. Just like the hitchhikers, these women received many more emails when they wore red T-shirts. Twenty-one percent of their emails arrived when they wore red, whereas the other colors—black, white, yellow, green, and blue—attracted 14 to 17 percent of the total. 
Why does red trump other colors in the mating game? There are at least two possible reasons, one more convincing than the other. The weaker reason is that we’ve been conditioned to associate red with love, passion, and romance. Red is the color of hearts and roses, lipsticks and rouges, sex districts and femmes fatales, and the letter “A” that advertised Hester Prynne’s adulterous past in Nathaniel Hawthorne’s Scarlet Letter. But where does this association come from? Why aren’t yellow, black, blue, or green associated with love?  The ultimate origin of red’s romantic past probably reflects the second reason: Animals, from humans to baboons to finches, flush red when they’re sexually receptive. A woman’s skin tends to redden as she approaches ovulation, and then lightens during the infertile midpoint of her menstrual cycle. The rush of blood that accompanies flirtation also reddens the face, neck, and upper chest, reinforcing the link between redness and sexual receptiveness. The good news for men is that red clothing makes them more appealing as well (men also blush red when they’re sexually excited), and that people across the world—from the USA to China to Germany—show the same preference for red-clad mates. Since the effect isn’t confined to just one culture or species, and disappears when the rated women are post-menopausal (and therefore no longer fertile), it’s safe to assume that animal biology explains at least part of the effect.
Colors influence our judgments in other contexts as well. In the late 1980s, Mark Frankand Tom Gilovich analyzed the penalty records of 21 National Hockey League and 28 National Football League teams. Five teams in each league happened to wear mostly black uniforms, and since black is associated with evil and aggression, the researchers found that those teams were called for more penalties than their lighter-clad counterparts. In the late 1970s, the Pittsburgh Penguins and Vancouver Canucks traded in their nonblack NHL uniforms for black uniforms, and almost immediately began conceding more penalties. Frank and Gilovich also showed that students behaved more aggressively when they wore black uniforms, and believed other students were more aggressive when those students wore black as well.
Like women, men are more attractive to potential suitors when they wear red clothing.
Like women, men are more attractive to potential suitors when they wear red clothing
Photos courtesy of American Apparel
At the other end of the spectrum, researchers seized on a bright pink color in the late 1970s that appeared to calm aggressive prisoners. Gene Baker and Ron Miller, two naval officers at a corrections center in Seattle noticed with frustration that aggressive inmates were just as violent after cooling off in solitary confinement. Psychologist Alex Schaussoffered the officers a novel solution. In a series of experiments, Schauss found that healthy young men were weaker after staring at a sheet of bubblegum pink cardboard. Baker and Miller ran with the suggestion, and painted the inside of one of their holding cells with the bright pink hue. According to legend, prisoners entered the cell angry but emerged 15 minutes later pacified and relaxed. The facility normally saw dozens of aggressive incidents, but not a single inmate who spent time in the pink holding cell behaved violently in the ensuing nine-month period. The effect briefly infiltrated popular culture, and football coaches at Colorado State and the University of Iowa began painting their visitors’ locker rooms with the same color pink, hoping to weaken their opponents. Local athletics conferences eventually intervened, cleverly requiring that home and visitors’ locker rooms were decorated identically. The famous shade of pink, affectionately known as Baker-Miller pink, or Drunk Tank Pink, has a number of detractors, but Schauss and his supporters maintain that the color’s effects are real.                 
Black and red and pink have a remarkable capacity to shape our thoughts, feelings, and behaviors in contexts that defy belief. It seems crazy to suggest that the same person can be luckier in love because she wears a red T-shirt, that the same football player becomes more aggressive when he dons a black uniform, and that strongmen become weak in the presence of pink paint—but, at least as far as experimental evidence goes, those effects are real. And of course colors aren’t the only incidental features of the world around us that influence how we think, feel, and behave. What these examples show is that a huge part of our mental lives goes on, like the proverbial iceberg, below the surface of conscious awareness—something to think about the next time you compete for love in the over-populated waters of, OkCupid, and eHarmony.

Wednesday, March 20, 2013

Mark Rothko's Purpose

Did Mark Rothko try to ellicit a response from his viewers, or did he just paint? Since he didn't write about his motivation, we can only guess. The following article explores the idea of a premeditating painter.

Color Blocking

Emotion lurks beneath the surface in Mark Rothko exhibit

Images Courtesy Columbus Museum of Art
In simplest form, Russian-American artist Mark Rothko painted blocks of color. But there is so much more than just describing his art as shapes, explains Columbus Museum of Art curator Dominique Vasseur.
“He’s painting to communicate something,” he says. Through layers of hues on canvas, Rothko’s intent is to rile the viewer’s emotions, to elicit a primal response.
Just how Rothko arrived at his signature style can be seen in CMA’s “Mark Rothko: The Decisive Decade 1940-1950,” running Feb. 1 through May 26 and featuring 27 works by Rothko alongside 10 pieces by his contemporaries. The works from this influential decade show the artist’s journey from painting recognizable subject matter to abstract uses of color. Here, Vasseur shares insight into Rothko’s emotional intent.

1945 "Sacrificial Moment”

“Rothko believed everything we know about the human condition was stated in Greek mythology,” Vasseur explains. Tiring of relying on human forms to tell stories of tragedy, love and doom, Rothko begins to blur the line. By the mid-’40s, he disembodies subjects until only outlines remain (like a knife seemingly shown here). And pay attention to the background, Vasseur adds, pointing to the three bands of color behind the subjects. It’s an allusion to what viewers already know: that Rothko will realize he doesn’t need objects to express action.

1948 “No. 10”

As the decade winds down, Rothko’s multi-forms begin to morph toward his signature style. “He keeps pushing it and pushing it. He gets at this idea of blocks of color that carry weight and meaning,” Vasseur explains. “You see a lot of over-painting. A lot of thought and afterthought.”

1949 “Untitled” (at the top)

“Finally he arrives at the idea of order,” he says. Veils of color are painted over other hues—a ghostly touch that carries great meaning. “There is an action, a drama occurring in the background. It requires you to look at the painting seriously.”

Getting Emotional

Rothko didn’t want to tell viewers how to feel; he was never candid about which emotions his paintings were meant to convey. So go to the exhibit with an open mind, says Vasseur, who suggests a few more ways to get the most out of the show.
Keep an eye out for themes of threes. Many of Rothko’s earlier images riff on creatures three in number.
Take a closer look. “Look overall and then at the parts,” he says. More than mere blocks of color, Vasseur explains, Rothko used layers of paint to distill a sense of meaning and create a dialogue.

The Artist on Stage

It was an offer artist Mark Rothko couldn’t refuse—a career-changing commission to create artwork for the Four Seasons restaurant in New York City in the late 1950s. He accepted the job, despite fears that his works would be nothing more than decorative pieces.
The ensuing question—can commercial art be truly considered art?—is weighed in “Red,” a 2010 Tony Award-winning play that debuts in Columbus this month in conjunction with the Columbus Museum of Art’s Rothko exhibition.
“What I love about ‘Red’ was it really helps us look at this massive color canvas and understand what he’s trying to do,” says Steven Anderson, producing director of CATCO, which is putting on the play.

The two-person performance focuses on a conversation between Rothko and his assistant, a fictional character based on a number of influential people in his life. At first the assistant is intimidated by Rothko, but eventually he begins to question his commissioned venture.
“It certainly does ask the question,
‘What is the purpose of art in our lives?’ ” Anderson says.

Saturday, March 16, 2013

Home Exterior Color Contest

Polymer Roofing Company Launches Home Exterior Color Contest

I heard of this contest today. It would be neat to have the exterior freshened up this spring. The deadline is near, so if you are interested, enter soon. I hope one of us wins! If you do, let me know and I will do likewise.

Polymer Roofing Company Launches Home Exterior Color Contest

Published on March 16, 2013 at 5:41 AM

DaVinci Roofscapes®, the color leader in the polymer roofing industry, launches a home exterior color contest on March 18, 2013. Open to all homeowners nationwide, the "Shake it Up" Exterior Color Contest includes a $5,000 cash grand prize to help the winner add color to the exterior of his or her home.

Colorful home exterior gains curb appeal. (PRNewsFoto/DaVinci Roofscapes)
To enter the contest, homeowners should visit the DaVinci Facebook page at After "Liking" the page, a person can enter by submitting a digital photo of their home's exterior along with up to a 250-word description stating how they wish to "shake up" the exterior of their home with colorful products.
National color expert Kate Smith will help judge the contest to determine five finalists. She will then work with a professional artist to create renderings and product wish lists of how the five finalists can transform their home's exteriors by adding color and colorful products by the contest sponsor and partners. The original photo submission and the artist's renderings for the five finalists will be posted on the contest site for two weeks of online public voting. The finalist with the most votes will receive the $5,000 grand prize.
"This fun contest will show people how easy it can be to add 'top down' color to a home's exterior," says Smith, president and chief color maven of Sensational Color. "We're going to help people turn ordinary home exteriors into extraordinary, color-coordinated showstoppers!"
The contest sponsor, DaVinci Roofscapes, offers polymer slate and shake roofing tiles in 49 standard colors with the option to custom create any color a homeowner desires. Each of the product partners for the contest, including Therma-Tru, Fypon and Simonton Windows, offers colorful product options for homeowners to enhance their home's exterior.
The "Shake it Up" Exterior Color Contest is open for online entries from March 18 – April 21, 2013. After the selection of the five finalists, public online voting will take place from May 13 – 26, 2013. The grand prize winner will be announced on June 3, 2013. For more information, along with the entry form, complete rules and regulations regarding the contest, visit


Wednesday, March 13, 2013

Does She or Doesn't She?

How Clairol Hair Color Went From Taboo to New You

Hair dyeing shifts from shameful secret to $1 billion bonanza

Throughout history, women have grappled with a biological inevitability that is, literally, always top of mind: Sooner or later, they go gray.
As the common wisdom goes, about 50 percent of women will be 50 percent gray by the time they turn 50. Men go gray too, of course, but they don't seem to agonize over it the way women do (they have other worries, like baldness). In fact, according to WebMD, 75 percent of American women admit to color-treating their hair. Among men, it’s only 11 percent.
Given these realities—both biological and social—it's no surprise that hair-dye ads aimed at women have been with us for three generations now. The ads on these pages show us that much, but they also show us something far more interesting. While the process of coloring hair has remained largely the same, attitudes about it have not. "It’s a generational thing," said Marti Brady, president and co-founder of consulting firm Beauty Management Group. At one time, women routinely concealed the fact that they dyed their hair. Many just lied about it. But today? "Most people don’t care," Brady said, “so long as they look good.”
In 1956, Clairol had a problem on its hands. Its new Miss Clairol "hair color bath" not only achieved natural-looking results in just one step, but women could also use it at home. The problem was the social stigmas tangled up in the practice of dyeing hair. Historically, most women who colored their locks either worked the stage or, worse, the sidewalk.
The task of destigmatizing hair coloring fell to Shirley Polykoff at Foote, Cone & Belding. As the agency's sole female copywriter, Polykoff understood that the key to selling Miss Clairol was to reassure its buyers that the color they’d get from that little box would be so natural, nobody would ever guess. Her tagline "Does she...or doesn’t she?" did the necessary reassuring so perfectly, it remains one of the most successful slogans in advertising history.
By the time this 1962 ad appeared in Life, Miss Clairol sales were already well on their way to $200 million—up from $25 million when Polykoff got the account. This little piece of marketing genius was actually a one-two punch. The "Does she or doesn't she?" question hovered at the ad’s center. Its predicate ("…only her hairdresser knows for sure") hovered further down. The line’s success hinged on relieving the uptight mores of the era itself, Brady said. “Back then, everything was so much more formal. Women got dressed up to go to the store.”
Today, of course, not only do plenty of women not care what they wear to the store, but they also don't care if anyone knows they dye their hair. In a social sense, that’s probably a good thing. The inadvertent result, however, is the disappearance of innovative advertising. The 2013 ad for Clairol’s Nice 'n Easy, Brady said, "looks like all the other beauty ads. There’s nothing iconic about this."
Nope. But you have to admit, those blond locks sure look natural. Makes you wonder if she dyes her hair or not. Hmmm. Does she or doesn't she?
Only my hairdresser knows for sure. BBL

Wednesday, March 6, 2013

Glass of All Colors

Sand and fire are required to produce glass, one of the most beautiful vehicles for color on our planet. Today is my birthday, and if I could, I would visit this incredible shop, The End of History, in NYC to select a piece of glass, or a vase, or a paperweight. The owner, very wisely, takes a piece home and returns with another, so he won't hoard them. But, it would be hard for me to choose just one.

Elizabeth D. Herman for The New York Times
Stephen Saunders, the owner, showed one of his most valuable pieces, a $16,000 piece of pottery made by Berndt Friberg. More Photos »

 Organized by color and form, the pieces on display form an eye-popping Technicolor tableau, clustered in islands of cerulean, ivory, amber, ebony and bubble gum pink.
On one shelf, Italian Murano glass geode bowls beckon in hues of green and turquoise blue. On another, glossy, undulating orange vases — representatives of the Danish manufacturer Holmegäard’s coveted 1960s Carnaby series — form a sort of Pop Art fantasia. A 15-inch-long Murano tiger the color of a sunrise lurks above them. “It’s a fantastic object, one of a kind,” Mr. Saunders said of the $2,750 creature, adding, “I don’t love figurines unless they speak to me.”
Mr. Saunders’s passion for glass goes back to his childhood on the Isle of Wight, where he had relatives in the antiques business. “At 7 years old, I was picking the best rummage sale on the island,” he recalled. He arrived in New York in 1983 after moving on a whim from Honolulu, where he worked in the travel industry.
Although Mr. Saunders subsequently spent more than a decade as a fashion stylist, he was always buying and selling glass. His “light bulb moment,” he recalled, came at a flea market when he found a 1951 Murano glass vase with an original $350 price tag still on it, on sale for $25. “I started to buy every piece I could,” he said.
His shop’s somewhat inscrutable moniker was inspired by Francis Fukuyama’s book “The End of History and the Last Man.” When he opened his doors, said Mr. Saunders, 54, “the millennium was coming up and the store was full of all these 20th-century things.”
At the time, he said, Hudson Street was “the cheapest place to open a store.”
“There was no Marc Jacobs or Richard Meier towers,” he said. “Everything has grown up.”
The area’s gentrification has been good for business: His regular customers include well-known decorators like Amy Lau, Steven Gambrel and Shawn Henderson, and the bulk of Mr. Saunders’s inventory — priced from $250 to $16,000 — goes into the homes of wealthy families. But visitors arrive from around the world, he said, remembering a woman from Taipei who came in “waving a picture of a Danish Modern vase from New York magazine, saying, ‘I have to have this!’ ”
Brazilians “absolutely love this stuff,” he added, recalling a day when the actress Sonia Braga saw the store while riding past it on a bus and made the driver let her out.
As they browsed, Mr. Saunders pondered a shelf of his “latest obsession,” white German porcelain tattooed with intricate gold embellishments. “Inasmuch as an object has a soul, these have that because they were made with care and with love by skilled people,” he said. “They have a life and a story to tell.”

Friday, March 1, 2013

Changeable Charlie Colors

Materials scientists at Harvard University and the University of Exeter have invented a new class of polymer fibers that change color when stretched. As is often seen in nature, the color is not the result of pigments, but rather comes from the interference of light within the multilayered fiber. Inspired by Margaritaria nobilis – also known as the Bastard Hogberry – the new fibers may lead to new forms of sensors, and possibly to smart fabrics whose color changes as the fabric is stretched, squeezed, or heated.
The play of color across a peacock's feathers, the iridescent inner surfaces of certain seashells, the rainbows seen on soap bubbles, or the colors of a fine opal, which seem to float somewhere within the stone – all these are examples of structural colors. In contrast to colors that appear because of absorption of certain wavelengths of light by pigments, structural colors are the result of optical interference of light reflected from nanoscale structures on a surface. Rather like a diffraction grating, the color you see is not that of the substance from which a surface is made, but rather is characteristic of the shape of that surface.
The brilliant blue iridescence of the Morpho Agea butterfly is the result of submicron sur...
The brilliant blue iridescence of the Morpho Agea butterfly is the result of submicron surface structures – the wing is actually brown (Photo: Peter Ruhr)
Bastard Hogberry (BH) plays a role in the diet of many birds and of Capuchin monkeys in Central and South America. Unfortunately, its fruit is not very nutritious, so would be shunned by animals who spread its seeds were it not that its bright blue color mimics the fruit of a far superior competitor. The coloring probably evolved as an adaptation – the more its fruit was mistaken for other species, the more widely its seeds were spread.
But where did the color come from? It is harder to make blue pigments through biochemistry than, say, yellow or brown pigments. Blue pigments require an arrangement of high-energy electrons that is expensive for an animal or plant to produce. The excess energy of formation of a blue pigment would have to come from somewhere, which suggests that a jump to a substantially different biochemistry would be required to suddenly start making a blue pigment – an unlikely evolutionary direction.
Nature tends to reuse its abilities whenever possible, and that is the route taken by the Bastard Hogberry. On examining the microscopic structure of a typical BH fruit, the color of the fruit is found to be caused by optical interference of incoming light interacting with a highly complex nanostructure.
The structure of the Bastard Hogberry under increasing magnifications, eventually revealin...
The structure of the Bastard Hogberry under increasing magnifications, eventually revealing the source of its bright blue coloration
In the figure above is a BH fruit as it appears at a wide range of magnification. The upper left photo is of a single BH fruit about one cm in diameter. The upper center photo shows a section about a millimeter across, and shows strips of blue cells. On the upper right is a scanning electron micrograph about 100 microns across, showing a cross-section of the outer layers of the fruit revealing layers of cells.
At the bottom left is a view about 50 microns across showing a cross-section of a single tissue cell, revealing its concentric, slightly flattened cylindrical multilayer structure. Finally, at bottom right is a 2-micron wide view showing details of the stacked layers. In this final image it becomes clear that the layers are actually bilayers – one material upon another, and that bilayer then makes up the cylindrical multilayer structure of the hard inner layer of the BH fruit.
This was the key observation. The fruit cells look like a periodic stack of bilayers from every direction. As each of the materials making up the bilayers has a different index of refraction, the multilayers form Fabry-Perot dichroic filters which reflect one characteristic color. The color of the light depends on the thickness of the bilayers and the difference of optical properties in the two materials making up the bilayers.
In the case of BH fruit, the fibers reflect blue light and transmit other colors to be absorbed in the brown underlying plant material. The color is the same from any angle around the axis of the cylinder, but varies when the viewpoint is not perpendicular to the cylinder axis. This leads to the iridescence of the blue color.
“Our new fiber is based on a structure we found in nature, and through clever engineering we’ve taken its capabilities a step further,” says lead author Mathias Kolle, a postdoctoral fellow at the Harvard School of Engineering and Applied Sciences (SEAS). “The plant, of course, cannot change color. By combining its structure with an elastic material, however, we’ve created an artificial version that passes through a full rainbow of colors as it’s stretched.”
To make the artificial color-changing photonic fibers, the members of the Harvard-Exeter team mimicked the optical structure of the fruit cells using an novel roll-up mechanism perfected in the Harvard laboratories.
Diagram of how the new Harvard fibers are made
“For our artificial structure, we cut down the complexity of the fruit to just its key elements,” explains Kolle. “We use very thin fibers and wrap a polymer bilayer around them. That gives us the refractive index contrast, the right number of layers, and the curved, cylindrical cross-section that we need to produce these vivid colors.”
The appearance of the new Harvard color-change fibers, as the fiber is stretched to double...
The appearance of the new Harvard color-change fibers, as the fiber is stretched to double its original length
As you can see above, the result was quite successful. But why does the color of the fiber change as it is stretched? Think about stretching a rubber band. As you do, the rubber becomes thinner and narrower. The more you stretch, the thinner it becomes. This phenomenon is called the Poisson effect, and to some degree occurs in most elastic materials.
As one of the new fibers is stretched, the bilayers become thinner, so to keep the optical conditions that produce the fiber color the same, the reflected color will shift to having a shorter wavelength. If an unstretched fiber has a red color, stretching the fiber will change its color to orange, yellow, green, and then finally blue as seen above. In that example, the wavelength becomes about 35 percent shorter as the fiber's length is doubled by stretching.
Other optical effects occur in the new fibers, based on the same principle. For example, if you apply pressure perpendicular to the fibers to compress them, two things happen. One is that the bilayers that are being squeezed become thinner, so their color in the direction of the pressure moves toward the blue. On the sides, however, the bilayers actually become a little thicker, which moves the color perpendicular to the pressure toward the red.
So, pressure causes the fiber colors to shift with the viewing angle, an effect that could be fascinating in a "smart cloth" made of these photonic fibers. The color will also change with the temperature of the fiber, due to thermal expansion. Higher temperatures cause a shift to redder colors.
“Our fiber-rolling technique allows the use of a wide range of materials, especially elastic ones, with the color-tuning range exceeding by an order of magnitude anything that has been reported for thermally drawn fibers,” says coauthor Joanna Aizenberg, Amy Smith Berylson Professor of Materials Science at Harvard SEAS.
Athletic spandex that change color as you move? Superhero costumes whose color changes to tell you who is winning the latest battle? Adaptive camouflage that can change patterns by controlling a heating grid within the fabric? Or (more likely), packaging materials whose color tells you if the wrappings are about to burst? There are a wide range of applications for this new class of photonic fibers just awaiting further development and commercialization. I can't wait!
Source: Harvard University
About the Author
Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer. All articles by Brian Dodson
Scientific explanations can be intriguing and I find the article above mind blowing. Studies of natural phenomenon used as a jumping off spot for research are valuable.