Tag Archives: Isaac Newton

Can Color Exist in the Dark?

Can Color Exist in the Dark (c) tlr3automatonColors add beauty and variety to the world around us. They are pleasant from every perspective – expect the dark. After all, color cannot be seen without light. Or can it?

Color is created when light reflects an object. Light waves cause this to occur and the frequencies at which they travel, fast or slow, determines color. For instance, red has a low frequency while purple has a high frequency. If there is no light, there can be no light waves and color cannot be seen.

This is true most of the time. There is only one exception: items that glow in the dark.

Glow in the Dark

Glow in the dark products contain phosphors. These chemical substances are known for their luminescent qualities. All phosphors have three characteristics. These traits include:

  • They need to be charged. Different glow in the dark objects require different types of energy to become charged. (This is why some items need to be held up to a light before glowing in the dark.)
  • Phosphors contain the “color of visible light that they produce.”
  • The persistence of the phosphor (or the length of time the product will glow).

After becoming charged, a phosphor will illuminate. This item can be seen in the dark where other colors cannot be seen.

We Use Phosphors Every Day

Toys “R” Us seems like the keeper of all-things glow in the dark. In everyday life these items seem far and few between. But adults use phosphors every day.

Television screens, computer monitors, and fluorescent lights all have phosphors. TV screens actually have thousands of phosphors that emit red, green, and blue. Fluorescent lights have many color combinations that make light look white.

Charging Items to Glow in the Dark

The charge that generates TV and lights comes from electricity. But other phosphors use different types of energy to charge. Much of the time, natural energy is used.

For instance, glow in the dark toys are often energized by normal light. To capture this charge and maintain it for some time, two phosphors are common: Zinc Sulfide and Stontium Aluminate. These chemical substances can be mixed in with plastic to create a toy that glows.

Some glow in the dark items do not need any charge. Take watches for example; a watch may use a combination of a phosphor and radioactive element. The radioactive part can continually charge the phosphor.

With phosphors, light can thrive in the dark. Better yet, items can glow.

Image made available by  tlr3automaton on Flickr through Creative Commons Licenses.

Read more Segmation blog posts about “Out of the Box” Art:

Art Illuminates Science

The Op-Art of Josef Albers

Art and Science – A Genius Combination

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Photography: Black and White or in Living Colors

Does anyone remember a time before color photographs?

When photography began to flourish in the early 1900s, the camera produced only black and white images. However, a desire stirred inside many people, like physicist James Clerk Maxwell, who wrote about the first technique used to color photographs in 1855. Through his work, other photography enthusiasts were able to develop the capacity to capture life in living colors.

Maxwell predicted that it was possible to capture the essence of a photograph—the arrangement of color—in a time when only black and white photographs were produced. He wrote about color vision; a study to advance the concept that color identified by both human brains and machines is based on the wavelengths of light that reflect, emit, or transmit color signals. Maxwell found that a wide range of colors could be created by mixing only three pure colors of light: red, green, and blue. This manipulation of color had to be done in proportional amounts to stimulate the three types of cells the same way “real” colors did. In his writing, Maxwell used black and white photography as an analogy for his findings.

Maxwell’s Analogy:

If three black and white photographs were taken of the same setting through red, green, and blue filters, then made into transparencies (also known as negatives or slides), one could project light through these filters and superimpose them into a single image on a screen. The result would be an image that reproduced all of the colors seen in the original setting, not just red, green, and blue.

At this time, Isaac Newton’s work advancing the fact that all color is influenced by light, was common knowledge. In a similar fashion, Maxwell insisted that eyes see color on the surface of a perceived shade, where millions of intermingled cone cells represent only three colors. Red and blue sit at opposite ends of the spectrum with green planted as a middle region. They signal sensitivities (red) and stimulation (blue) that eyes receive when light shines through particular colors. The process of taking a set of three monochrome “color separations,” was also known as the triple projection method. Maxwell’s analogy was first tested by Thomas Sutton in 1861. However, the experiment did not work and the desire for photographs to represent living colors encouraged other enthusiasts to develop the art of color photography, which picked up steam again in 1890.

Color photography has been around for a little over one hundred years, and look at how far it has come. Flawless colors and mass production of images show how color photography has influenced enthusiasts and much of the world. This, however, is made possible because of the records kept during photograph exposure, like the triple exposure method which was outlined in Maxwell’s analogy. At the end of the appropriate exposure time, analyzing the spectrum of colors into three channels of information, red, green and blue, helped form a method to imitate the way a human eye senses color. The recorded information has been used to reproduce and enhance the original colors by mixing together aspects of the red, green, and blue lights and removing or adding elements of white light.

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