Energy Absorption by Color
Can anyone tell me if there is a list of colours that are
better for absorbing heat than others? I know that black is best and
white is bad, but where is blue in this scenario?
There is not one category that represents color
The hue of a color establishes its wave length in the visible spectrum.
The saturation its vividness.
The hue with saturation being a modifier.
This needs checking, but I thought the shorter wave lengths were darker,
hence capable of absorbing, more dense.
The more I think of the color wheel, there is another scale, lightness which
I think measures the degree of white.
Blue can be any shade from Navy blue
to powder blue. Saturation measuring the
black, Light the white. Naturally, everything needs to be reduced to
numbers, for consistency and reproduction, hence the scales. The three
categories identifying the specifics.
Radiant heat is radiation having a wavelength greater than about 700
nanometers (infrared radiation). It is ultimately the absorption of
infrared radiation that determines how effective a surface absorbs "heat".
The process is a bit more complicated because some surfaces will absorb
visible light or even ultraviolet light and through a series of steps
convert that radiation into infrared i.e. heat. In general, all the
visible colors are about equally effective in this conversion (if other
factors are equal). However, there are even some other factors that come
into play in certain circumstances. Some metals will absorb infrared
radiation very efficiently and reflect very little of it, and so become
much hotter when exposed to sunlight. This is the reason for the title of
the play "Cat on a Hot Tin Roof".
Click here to return to the Engineering Archives
Update: June 2012