Tints, Tones and Shades
In color theory, when you mix a hue with white, the result is a tint, and the more white you add, the lighter and more pastel the color becomes. A tone is the result of mixing a hue with gray, and when you mix a hue with black, the result is a shade.
Note the more saturated (intense) color on the left side of each strip, and how it changes, becoming less and less identifiable as the starting hue, which is the same orange in each row.
A Single Approach to Wall Color is Best
Color is very personal. We all see it differently and we're entitled to have our own ideas. I personally don't enjoy houses where both tints and shades are used in large areas, such as on the walls, because they feel incompatible and disrupt the flow of color. If a room is pale pink (a tint of the hue red) and the next room is dark olive (a shade of the hue green), it isn't pleasing to me, even though red and green is a classic color combination. However, if tint versions of red and green were used on the walls, or the tone or shade versions of these colors, the results would be much more cohesive and attractive, and enhance the value of the house.
These samples illustrate how different a tint color is from a shade color, and why using both in the same house can disrupt the "flow" from room to room.
In our area, walls painted in tint colors, whether they're pastel or chromatically intense like the tint green example, feel somewhat harsh and out of place in most situations, except perhaps modern buildings or certain businesses or institutions. They definitely don't suit more rustic architecture. Even in a baby's room, I think a toned hue in a light color works better than a pale tint, and is easier to live with.
To avoid a tint-shade problem with your wall colors, decide the look you want and start training your eye. When you go to the paint store, look at the color displays and identify the tint sections, where the colors will look significantly lighter and brighter than the rest, because they include white. Make a conscious decision about the look you prefer, then shop for colors from that area of the display. Don't jump around!
Tone Colors: The Perfect Compromise
I think tone colors, which are a hue plus gray, represent the perfect compromise between brightness of tint colors and the somber look of shade colors, and are well-suited to most houses in our area. Tone colors can be pale, or they can be dark. Think of them as a little softer.
Don't get me wrong, I'm not saying you should never use tints, or that you should never mix tints and shades. Quite the contrary! In smaller amounts than on the walls, such as in art, furniture or pillow fabrics or trim, or in ceramic pieces, more extreme colors can look fabulous and provide a desirable, lively or dramatic touch to your color plan. Just be careful how you combine them with more subdued hues. Keep the proportions relatively small, and use them as the icing, not the cake. You'll find the results are more harmonious and pleasing than a mix of tints and shades on your walls.