Value and intensity are two different things. Bright red has a dark value close to black, Bright yellow has the same light value as a pale blue.
Did you know that value is the first aspect of color registered by the eye? We see patterns primarily based on a color's value. The value or the tone of a color is measured by it's relative lightness or darkness on a gray scale. If I want my quilt patterns to pop and move I make sure that the color value of the patchwork pieces contrast between light and dark. If I want my patterns to blend then the color values of the patchwork pieces will vary only slightly.
This is because color value affects spacial relationships. When values contrast the spacial relationships of the pattern appears to have more depth. Dark colors recede from the eye, and light colors come to the foreground. When values are similar, then the pattern flattens out. Hence the popping phenomena quilts sometimes exhibit, when using highly contrasting values. There are other color principles that make things pop, such as intensity or saturation, and the clashing of hues, which I'll talk about later.
Another important thing to keep in mind is that color value is relative - hence the term value. If you place royal blue next to sky blue then the royal blue has a darker value. If you place the royal blue next to navy then the royal blue has a lighter value.
I always check to see if I have a full range of values when choosing a color palette of fabrics for my quilts. There are several ways to check the color value of your palette. Squinting at your choices will dim the color and let the value stand out. You can buy a red tinted monochromatic value finder to view your palette through, or use a piece of red film, or the red half of an old pair of 3D glasses. I actually wear an old funky pair of red tinted sun glasses.
Practice your ability to see value by ordering your fabrics from light to dark. Make a black and white photocopy of swatches from your palette, or photograph your selections using a black & white setting on your digital camera, or edit a color photograph with image editing software on your computer, as I did above. The results may surprise you.
In what ways do you utilize or consider color value when designing or composing your quilts?