Actinism
Encyclopedia
Actinism is a property of radiation
Electromagnetic radiation
Electromagnetic radiation is a form of energy that exhibits wave-like behavior as it travels through space...

 (particularly solar radiation) that leads to the production of photochemical
Photochemistry
Photochemistry, a sub-discipline of chemistry, is the study of chemical reactions that proceed with the absorption of light by atoms or molecules.. Everyday examples include photosynthesis, the degradation of plastics and the formation of vitamin D with sunlight.-Principles:Light is a type of...

 effects. Actinism is derived from Greek with the meaning a radiant force. The word actinism seems to be used particularly in terms of imaging technology, especially photography, although it is used in medical literature for photo-biochemical effects such as a sunburn or radiation exposure from ultraviolet rays
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

, and in chemistry
Chemistry
Chemistry is the science of matter, especially its chemical reactions, but also its composition, structure and properties. Chemistry is concerned with atoms and their interactions with other atoms, and particularly with the properties of chemical bonds....

 for containers that protect from photo-degradation.
Chemical photography and X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 imaging
are two applications of actinism.

Actinic chemicals include silver salts used in photography and other light sensitive chemicals.

In chemistry

In chemical terms, actinism is the property of radiation that lets it be absorbed by a molecule and cause a photochemical reaction as a result. Einstein was the first to correctly theorize that each photon would be able to cause only one molecular reaction. This distinction separates photochemical reactions from exothermic reduction reactions triggered by radiation.

For general purposes, photochemistry is the commonly used vernacular rather than actinic or actino-chemistry, which are again more commonly seen used for photography or imaging.

In medicine

In medicine, actinic effects are generally described in terms of the dermis or outer layers of the body, such as eyes (see: Actinic conjunctivitis
Actinic conjunctivitis
Actinic conjunctivitis is an inflammation of the eye contracted from prolonged exposure to actinic rays. Symptoms are redness and swelling of the eyes. Most often the condition is caused by prolonged exposure to Klieg lights, therapeutic lamps, or acetylene torches...

) and upper tissues that the sun would normally affect, rather than deeper tissues that higher-energy shorter-wavelength radiation such as x-ray and gamma might affect (see actinic keratosis
Actinic keratosis
Actinic keratosis is a premalignant condition of thick, scaly, or crusty patches of skin. It is more common in fair-skinned people. It is associated with those who are frequently exposed to the sun, as it is usually accompanied by solar damage...

).

The term actinic rays is used to refer to this phenomenon.

In manufacturing

Actinic inspection of masks in computer chip manufacture refers to inspecting the mask with the same wavelength of light that the lithography system will use.

Artificial lighting

"Actinic" lights are a high-color-temperature blue light.

They are also used in electric fly killers to attract flies.

In aquaculture

Actinic lights are used in aquariums, primarily because they make fluorescent coral "pop" to the eye, but in some cases also to promote the growth of deeper-water coral, that is specialized in photosynthesis using blue light.

See also

  • Spectral sensitivity
    Spectral sensitivity
    Spectral sensitivity is the relative efficiency of detection, of light or other signal, as a function of the frequency or wavelength of the signal....

    is commonly used to describe the actinic responsivity of photographic materials.
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