Achieving Brightness

After a fun day of plein 
aire painting with a few 
friends of mine, we 
were sitting in a 
restaurant for a little 
libation and exchange 
of thoughts.   It was 
about 5 pm and the sun 
was on it’s last legs so 
I rushed outside with 
my camera and took a 
bunch of pictures of this 
scene. While uploading 
these to my blog it 
occured to me that this 
might be a good time 
to talk about brightness
in a painting.

Brightness is achieved by surrounding a light color with
dark, dull colors.  An object is only bright by comparison to a darker object next to it as you can see in the first comparison 
using yellow dots, to the right.  You will also note that the 
perceived colors of the dots, when compared with the same 
color dot beside it, seems to be darker or lighter and sometime 
will even take on some of the color next to it. 

I'd be interested in your thoughts and observations as always?