opaque medium

opaque medium

[ō′pāk ‚mēd·ē·əm]
(optics)
A medium impervious to rays of light, that is, not transparent to the human eye.
(physics)
A medium which does not transmit electromagnetic radiation of a specified type, such as that in the infrared, x-ray, ultraviolet, and microwave regions.
A medium which prevents the passage of particles of a specified type.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
At that time, space was undergoing the epoch of re-ionization - turning from a largely opaque medium to one in which light could travel freely, making it visible.
Both in the curtains and in the air they frame, Sugito is addressing the old challenge of rendering transparency with an opaque medium. The spiritual spaciousness connoted by these planes, it seems to me, is the paintings' strongest pull.
I turned to gouache, an opaque medium, and set out to paint symbols.
The addition of each opaque medium (11 [micro]L of medium to 1 mL of serum) to a control serum to reach the expected concentration after bolus injection for radiographic examination (7.5 g/L) led to the appearance of an abnormal peak in the CZE.