Grey and Ductile Iron

This article is about the colour. For other meanings of "gray" or "grey", see Grey (disambiguation).

Grey or gray (the latter more usually in American English) is a colour seen commonly in nature. It is created by mixing white and black in different proportions. Depending on the amount of light, the human eye can interpret the same object as either grey or some other colour.

Two colours are called complementary colours if grey is produced when lights of the two colours are combined. The psychological primary colours are:

• Black and White
• Blue and Yellow
• Red and Green

Other sets of complementary colours include:

• Orange and Azure
• Lime and Purple
• Jade and Fuchsia

Grey is its own complement. In an afterimage, which can be seen after seeing the picture for about 30 seconds, the colours will switch to their complements.

Usage, symbolism and colloquial expressions

• Grey symbolises mediocrity, the background noise.
  • "Grey life", meaning mere existence without much sense or goal.
  • A "grey person" is someone who goes unnoticed, a wallflower.
• In a moral sense grey is either used
  • pejoratively to describe situations that have no clear moral value, or
  • positively to balance an all-black or all-white view (for example, shades of grey = magnitudes of good/bad)
• Grey is associated with autumn, bad weather and sadness.
• Grey has been used to describe the industrialism as it is the colour of granite, concrete and other city materials, as opposed to green to describe environmentalism, chlorophyll and plants.
  • Urban camouflage is composed of patches of shades of grey, while country camouflage uses ranges of brown and green.
• Whilst the hair actually becomes white as one ages, it is often misinterpreted as grey (white next to others colours looking comparitively darker), and hence grey is associated with the elderly, and has inspired the name of the Gray Panthers.
• The substance that composes the brain is referred to as "grey matter", and for that reason the colour is associated with things intellectual.
• In religion, grey is the colour of ashes, and therefore a biblical symbol of mourning and repentance. It can be used during Lent or on special days of fasting and prayer.
• The "Grey Lady" is the nickname of the New York Times

In fiction

• In Tolkien's works:
  • Gandalf is called the Grey Wizard.
  • The Grey Havens
  • The Grey Elves
  • The Grey Hills
• In Michael Ende's Momo, the Men in grey purport to act as a bank of time, while they consume it themselves.
• In The T*Witches series, those of magical power are described as having grey eyes.

Colour coordinates

RGB 

All the grey values in greyscale are solutions of the inequality:

CMYK 

All the grey values in greyscale are solutions of the inequality:

when .

In theory it is also possible to achieve a greyscale with perfect inks when:

and

HSV 

All the grey values in greyscale are solutions of the inequality:

when .

Web colours

There are several shades of grey available for use with HTML and CSS. Oddly, all are named somethinggray except lightgrey: this can cause unexpected errors (this discrepancy is inherited from the X11 color list).

See also

• List of colours