They are shades of the rainbow—blues, yellows, reds, and greens—arranged in a luminous pattern of imperfect rectangles. They look like swatches of silk fabric. Or the tops of paintbrushes, one next to the other, dipped in multiple pots of color. Amazing to think that the glorious shapes in this digital photograph are actually the scales of a moth's wing. Magnified 100 times under a microscope, they are far more intricate than the shimmering wing you'd see with your naked eye. Charles Krebs, the photographer who took the image, is positively joyful when he talks about the drama of nature seen up close. "It's just absolutely stunning to peel off layer upon layer," he says. "Instead of getting simpler and simpler, it gets more complex."
It is called photomicrography—a process that allows scientists and hobbyists to create colorful and stunningly detailed photographs of nonliving objects and living organisms up close. Very close. Scientists have been documenting microscopic discoveries for centuries—first drawing them and then, with the advent of photography in the 1800s, taking pictures of them. Over the last two decades, digital technology has revolutionized the field, allowing researchers to capture details that have never been seen before in sharp focus. Nowhere is the power of photomicrography better documented than in Nikon's Small World photomicrography competition, which celebrates its 35th anniversary this year. In photographs dating back to 1977, crystals, neurons, larvae, knitting needles, fabrics, and hundreds of other organisms and objects reveal scientific information and artistic beauty. This week, Nikon announced its top 20 winners for 2009, the best of almost 3,000 entries from around the world.
In the 35 years since the contest began, technology has dramatically advanced the field of microscopic imaging. Early on, photomicrography faced the challenge that came with old-fashioned film: researchers couldn't see what they were capturing in real time, so they had to take multiple images to get one that was well lighted, well focused, and well framed. "It was always potluck to see what you would get at the end," says Alan Opsahl, a senior scientist in the Investigative Pathology Group at Pfizer. "You wasted a lot of film, time, and energy to get that perfect image." Today digital photography allows scientists to see their pictures as they take them and provides far more flexibility as they prepare their final images on a computer. Researchers can, for example, adjust colors to produce the most effective result. Opsahl did this with an image of mouse brain cells, which he submitted to Nikon's contest this year. In the original digital image, the biological stains he used labeled the nuclei of the cells blue and the cell bodies and processes brown. But Opsahl liked it the other way around, because it allowed the delicate neurons to stand out better. "I flip-flopped the colors, much like you do with a negative," he says. Nikon's rules state that photos must be taken with a light microscope—as opposed to an electron microscope, which can achieve even higher levels of magnification—but there are no restrictions on how color is used.
One of the greatest boons to the field is green fluorescent protein (GFP), discovered decades ago when researchers isolated a protein from a jellyfish that turned green under UV light. It wasn't until the 1990s that the use of a variety of fluorescent proteins, allowing scientists to illuminate samples in bright colors and, at the same time, see the inner workings of cell processes, became widespread in microscopic work. One of the most captivating examples of this is an image of a mouse embryo taken by Gloria Kwon, a Ph.D. student at New York's Weill Medical College of Cornell University. In Kwon's photograph, which won first prize in 2007, the mouse's bright red body is contrasted against the green yolk sac that nourishes it. The technique, known as fluorescence microscopy, has moved science forward in a major way, says Lee Shuett, executive vice president of Nikon Instruments, the division of Nikon that created the Small World competition, "but it has also created these incredibly startling photomicrographs."
So has the confocal microscope, a technological breakthrough that allows scientists to scan many thin samples, or slices, of their subject to create a three-dimensional image in perfect focus. At the Wistar Institute in Philadelphia, where he manages a microscopy lab specializing in cancer research, James Hayden has used a confocal microscope to create biological movies out of 3-D, time-lapsed images showing melanoma as it grows. As a result, scientists can observe the interactions between tumor cells and healthy cells. "It's that cell-to-cell communication that is key to a lot of research," he says.
But photomicrography is a celebration of both art and science, and Hayden is also captivated by whimsical images, like his dramatic close-up of an anglerfish ovary, which won fourth prize this year. The subject matter isn't relevant to Hayden's work, but it caught his eye artistically. Experimenting with fluorescence allowed him to distinguish the ovary and the eggs in bright colors. Hayden's picture of a tapeworm in a horse's gut, with its blues and pinks and greens, won seventh prize in Nikon's 1998 competition, and it also landed in a biology textbook and in scientific journals, says Hayden. "I have a foot in both worlds," he says.
Technological advances almost always raise new questions about how far to go, and Hayden, who teaches photomicrography to students, is quick to point out the ethical challenges. In the lab, doing research, scientists must be careful not to manipulate images, even in subtle ways, as it may alter the findings they are trying to present, he says. "That would not be an acceptable way of using the software or hardware or doing science." But when used responsibly, photomicrography is not only acceptable; it's revolutionary—and getting better. The field "has just stepped into the most exciting and absolutely most fruitful era of its life," says Shuett. Nikon's Small World competition is great branding and advertising for the company, of course, but it also invites us into a dimension of our universe that we live in every day but never see: a wonderful gift, a breathtaking adventure.