A third (and to me the most interesting) way to make a color less intense (less saturated) is by direct modulation. Direct modulation is adding amounts of the direct complement of the original hue. The direct complement is the hue directly opposite on the color wheel. In this case my original hue is blue, and its direct complement is an orange. In a gradation from 100% blue, through 50/50, to 100% orange at the other end of a series, the colors will be less saturated toward the middle of the series, and if they are true complements there should be a point at which there are "equal" amounts of red, yellow and blue, forming gray - a completely neutral, unsaturated color.
For my first direct modulation dye session, I guess I was thinking of orange as the color of an orange, that is, of the skin of an orange. Well, it turns out that is more of a golden color. So when I mixed this color with my blue, there was no point at which I got anywhere near a gray. Instead I got a nice selection of greens. There was never enough red in my orange to neutralize the blue and yellow.
For this particular blue, I needed a redder orange, more like a tangerine. My second trial was more successful. See the grayish hues in the middle of the series?
I think these more muted colors are so interesting that I did a couple more series using less dye, to get tints of the direct-modulated series.