Like ocean waves, light waves have measurable length, height and duration or frequency. Sunlight contains a continuous distribution of wavelengths. When arranged from long to short wavelength (low to high frequency), they form part of the Electromagnetic Spectrum.
We divide the spectrum into three sections: ultraviolet, visible and infrared. All three wavelengths can cause damage. Different materials and different colors absorb more energy than other materials and colors.
Light particles are called photons. Light is a collection of particles moving really fast in one direction. Think of water squirting from a hose.
Photons are little packets of energy. When they hit an object, the energy transfers, exciting electrons in the object. If the photon contains the right amount of energy the bonds between atoms break. This is how light fades colors, weakens some materials and causes other damage.
To see you need light and a receptor – your eyes. What you see is light reflected back off the object. Some visible light is absorbed by the object. A blue object reflects the blue part of the spectrum, absorbing other colors of light.
Why do exhibits sometimes seem dark?
Light intensity, the amount of light reflected by an object, and an eye’s ability to receive light all affect our perception of brightness. Aging eyes are less flexible and less able to accommodate rapid lighting changes.
If you step into the gallery from a bright area such as the atrium, exhibits may look dim. All eyes take longer to acclimate from bright to dark than they do from dark to bright.
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