Unless you are David Letterman, you wouldn’t wear white socks with a nice brown suit.
You know that they would draw attention to your ankles and take focus away from the nice brown suit and spectacular shoes.
Its the contrast rule. Again. The eye will go to the area of greatest contrast first. If your socks are the most important element in your outfit, then white is great. If, however, you would like them to stay in the background, socks in a color that blends with the suit or shoes is better. Unless you are David Letterman.
Using this guideline with regard to baseboards and window trim will help you determine what color to paint. Or to paint in the first place. If the trim is wood, and it is exceptional in some way, it may be appropriate to treat it as a focal point in the room and use the contrast rule to your advantage.
Stand at the end of a hallway that has several doors. Look at the number of horizontal and vertical lines created by the contrasting trim. When looking down the hall, your eye will stop and start at each contrast point. Imagine the hallway with all these contrast points negated. The hallway will appear much larger and less confined. Pictures or furniture in the hall will become the focus; not the trim and doorways.
Contrast will make an area appear smaller; lack of contrast will help an area appear larger. Trim on doors, walls and windows that is a contrast color will make the entire room appear smaller. Trim that blends with the surrounding wall will blur the edges, the walls will appear taller, the floor wider and the windows larger.
Decide what place you want the trim to take in the design scheme and paint accordingly. You can always re-paint if you make a big boo-boo. But, by understanding the contrast rule and with a bit of planning, this shouldn’t happen.
I have the facility to take a picture of your room, load it into my system and change the wall and trim color. It’s lots of fun to see what the effect will be before painting.
Update on colors for 2012. As mentioned, Pantone has selected an orange as color of the year. Benjamin Moore has selected Wythe Blue HC-143 (a very soft gray-blue) as theirs.