colors do bring some effect
space effect
mood effect
or just simply for the purpose of theme....

for me...
its more for mood and space...
my understanding based on my readings...
the darker the color....
it will reflect better space...
its like the wall is deeps ahead...
but bear in mind...
the darker part...if possible...shud be the minor area of the room only...
coz it will give bad lighting effect if majority of the area is in dark color....

those are the things that i learn about color for walls