Dark Cobalt Blue

Cobalt blue

Cobalt blue is a blue pigment consisting principally of cobalt(II) aluminate, CoAl2O4, made by sintering cobalt(II) oxide with aluminium(III) oxide (alumina) at high temperatures. It is used as a ceramic color, in automotive and industrial coatings, in scientific and medical imaging, and as a fine-art pigment. Its thermostability, chemical inertness, and lightfastness make it suitable for applications requiring a durable blue color.

Cobalt

Cobalt is a chemical element; it has symbol Co and atomic number 27. As with nickel, cobalt is found in the Earth's crust only in a chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, somewhat brittle, gray metal.

Darkness

Darkness is the condition resulting from a lack of illumination, or an absence of visible light.

Blue

Blue is one of the three primary colours in the RGB (additive) colour model, as well as in the RYB colour model. It lies between violet and cyan on the spectrum of visible light. The term blue generally describes colours perceived by humans observing light with a dominant wavelength between approximately 450 and 495 nanometres. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.

dark

Adjective

1. Having an absolute or (more often) relative lack of light.
2. Extinguished.

Noun

1. A complete or (more often) partial absence of light.
2. Ignorance.

cobalt

Noun

1. A chemical element (symbol Co) with an atomic number of 27: a hard, lustrous, silver-gray metal.
2. Cobalt blue.

blue

Adjective

1. Of a blue hue.
2. Depressed, melancholic, sad.

Noun

1. The colour of the clear sky or the deep sea; the colour midway between green and violet in the visible spectrum and one of the primary additive colours.
2. Anything coloured blue, especially to distinguish it from similar objects differing only in colour.