Shades of gray.

Back when our home office was upstairs we painted it a light gray, and we love it so much that when we converted the room to a nursery we chose to keep the same color. For months we tried swatch after swatch, each time determining the color to be too blue, too purple, too dark, etc. I wanted a light, warm shade of gray, like in this image.
I finally found a gray with the perfect undertones, but when I painted it on the wall it was too dark. At the home improvement store I showed my swatch and asked for a lighter version, and learned that the lighter colors on the same card are not necessarily just less saturated versions of each other. For example, the lighter shade of gray on my card used much more blue. So they simply whipped up a sample with only 50% of the formula (i.e. more white overall) and it is perfect! Here is Behr's "Dolphin Fin" at full color and the 50% solution.
When we decided to paint the basement a light gray (almost white) we went back to our tried and true "Dolphin Fin", this time having a solution of only 25% color mixed. It gives a subtle contrast to the white trim but keeps the space light and bright.