Greg,
Because above the candle flames there is a column of rising warm air. As
you go from left to right in the scene and arrive at the column of warm
air you are traveling from cool (room temp) air to warm air (in the
column) and on the other side of the column from warm air to cool air.
These gradients deflect light rays passing through them in opposite
directions. The deflected rays are made to pass through red and green
filters. Undeflected rays (such as those passing through the center of
the columns or on either side) are undeflected and pass through a
central, blue, filter.
This is a summary explanation sort of in 25 words or less so details may
be fuzzed out a bit. ;)
andy
Gregory Fraser wrote:
Hey Andy, why are the heat trails in this photo
http://people.rit.edu/andpph/schlieren-1.jpg orangy on oneside and
greeny on the other side?
Greg
