colour Flashcards
what is a perfect blackbody radiator?
.is a theoretical object that would absorb all the radiation that falls on it
.it would not reflect or transmit any radiation
. it is also best emitter
when does an object appear to be black?
. an object appears to be black if it absorbs all the wavelength of visible light
what happens happens to the temperature of body that absorbs IR faster than it emits?
. the temperature increases
what do coloured filters do?
. absorb light of certain energy
. let through one colour of light
e.g. orange filter will transmit only orange light
what is the property of white surfaces?
. worst absorber and worst emitter
why are home radiators white?
. so IR is emitted gradually
what happens to wavelength when you increase temperature?
.there is a shift in wave length when you increase temperature
.as the temperature rises , there is a shift towards shorter wavelength
what is the shortest wavelength?
blue/violet
what is the longest wavelength?
red
what is the wavelength with highest frequency?
blue/violet
what is CIE colour space?
. any colour is considered mixture of 3 CIE primaries (x,y,z), called Tristimulus values
. colours on the edges are more saturated
what is the structure of colour space?
. line of purples across the bottom . achromatic colour or white can produced with many different mixtures of light . top = green . bottom left = blue . bottom right=red
what is additive colour mixing?
. superposition of red , green and blue lights
. all visible lights can be obtained by the additive mixing of 3 colours.
what are primary colours?
. if 3 colours can be mixed to produce white they are called primary colours
what are the complementary colours for R,G,B ?
cyan
magenta
yellow
