Images that are produced on a fluorescent screen by X-rays.
1. A lamp with lenses or reflectors to collect the rays of light and throw them in a given direction; such as, those used in lighthouses.
2. An apparatus by which practically all the light from a lighthouse lamp or the like is thrown in a desired direction.
hyperphotesthesia (s) (noun)
, hyperphoesthesias (pl)
An increased sensitivity to light: With maturity, Nancy experienced hyperphotesthesia
in her eyes and always wore sunglasses when going outside and sometimes even when there were bright lights shining inside.
A well-known singer always appears on stage and on TV wearing shades because he has a condition of hyperphotesthesia.
hypophotesthesia (s) (noun)
, hypophotesthesias (pl)
A decreased sensitivity to light: Despite developing hypophotesthesia, Daniel’s ophthalmologist recommended he wear sunglasses when going outside in the sun.
A line (imaginary or in a diagram) connecting points where the brightness or the illumination is the same.
Photography in which objects are reproduced larger than or at their actual size but without the degree of magnification that use of a microscope would give.
Snow blindness; irritation of the conjunctiva caused by reflection of the sun on the snow.
It is characterized by photophobia, blepharospasm, burning pain in the eyes, hyperemia, or temporary blindness.
A descriptive reference to an orientation response towards light.
An orientation response towards light.
An electrical device for converting sound vibrations into light.
1. Photographic recording of the vibratory characteristics of speech sounds.
2. The recording on a moving photographic plate of the movements imparted to a diaphragm by sound waves.
A device for showing the vibrations of sound; especially, of voice sounds photographically.
A unit of illumination in the centimeter-gram-second system equal to one lumen per square centimeter.
1. Light-induced pain, especially of the eyes.
2. Ocular pain caused by light; also, photodynia.
An allotropic change with color alteration due to light, as the change of yellow into red phosphorus.
Allotropism is the existence of a substance in two or more distinct forms with distinct physical properties; for example, graphite and diamond, allotropic forms of carbon.