Yes.
Duskiness is a word that can be used to describe a darkening sky.
The word "shade" implies darkening. So, yeah, it probably is.
Yes. Darkening is most commonly used as a verb, but it can be an adjective. In a sentence like "Under the darkening clouds" it is an adjective.
Darkening Sky was created on 2010-10-22.
Fugue for a Darkening Island was created in 1972.
Mona on Darkening Ground was created in 2001.
The Darkening - 2012 is rated/received certificates of: USA:R
Fugue for a Darkening Island has 125 pages.
The Darkening - 1995 is rated/received certificates of: USA:PG-13
The ISBN of Fugue for a Darkening Island is 0-450-01575-0.
The ISBN of Mona on Darkening Ground is 1-58297-220-6.
Auto darkening welding helmets were invented by a Swedish manufacturer known as Hornell. One can purchase auto darkening welding helmets at popular on the web sources such as Miller Welds.