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n reactive dyes
Textile dyes (such as henna) that work as a result of a chemical reaction with the
molecules of the fibres, in particular, used with viscose and cotton.
n realgar
An orange-red pigment containing arsenic. See Titian’s colours.
a recalescent
Glowing with heat.
n receding colours
Blues and greens on a surface that have the effect of making it appear to recede;
also called cool colours and retreating colours. Compare advancing colours.
c reckitt
A cobalt blue after Francis Reckitt. Also a trade name of a blue used to whiten
laundry.
c red
The colour of blood. ‘Red’ derives from the Indo-European root r(e)udh meaning
ruddy and perhaps from the more immediate Sanskrit word rudhira meaning
‘blood’. The colour of revolution and communism; of tomatoes, strawberries,
fire appliances, stop lights and London buses. Of the visible spectrum, red has
the longest wavelength, that is, within the range of approximately 760 and 630
nanometres. Red is one of the three additive primary colours. An indicator
of danger and a symbol of courage as well as revenge; associated in medieval
times with the Zodiac signs Aries and Scorpio and with the planet Mars – the
‘red planet’. In English folklore red represents good luck, health and happiness
although it is also associated with the devil and blood and as an evil omen. See
black. According to W B Yeats (1865-1939) red is the colour ‘of magic in almost
every country’. An object which is moving away from earth shifts into the red
sector of the spectrum whereas it moves into the blue part if moving towards
us. Under the surface of water red can be distinguished as a colour up to a depth
of 150 feet. The corresponding depth for yellow is 300 ft while for green, blue
and violet the figure is 600 ft. Red is the colour next to the centre in archery. That
part of the roulette table on which a player puts his chips if he wishes to gamble
on a red number coming up. An article in the Journal Nature in March 2001 refers
to research showing that against a green background the human eye can identify
the colour red more easily than white. This facility possibly evolved as a result
of the need of primates to distinguish red (and therefore riper leaves) from green