I think I have an idea of what you're looking for, hair that goes from one color at the top and fades to a lighter color at the bottom. To achieve this look you actually need three different colors and possibly a toner, depending on how light you're going with the color at the bottom.
The way to get this look you need to start with three colors and foils to keep the colors from bleeding together. The colors should go from dark to light, this can be slight or more extreme. The hair needs to be sectioned and clipped so none of the colors touch. On your first subsection, which should be about one inch (in the wider parts of your sections you'll need two foils per subsection), you need to apply the darkest color to the root and down the hair. Then take your second color and blend the two together where the dark ends and the lighter color begins. You want them mixed very well on the hair so you don't get a solid line of demarcation. Do the same with the third and lightest color on the ends of the hair. Again, make sure the colors are blended together. you don't need to close this foil, you can just let the hair hold it in place. Take your next subsection and repeat the process but make sure you don't apply color to the same points as you did in the first subsection. For example if you applied color #1 to the roots and four more inches, color #2 to the next three inches and color #3 to the last one inch, then on the next foil apply color #1 to the roots and only two inches, color #2 to the next three inches and color #3 to the last three inches. The key to this look is that it isn't uniform all over the head, each piece has a different amount of color #3.
Just a note, if you aren't a stylist this is pretty difficult to do on your own hair. I would go in to a salon for this and tell your stylist you want your hair to fade from a dark color to a lighter one at the bottom with at least four levels between the two. Bring in a picture, because that's the easiest way for a stylist to understand what you want.
Sorry if this isn't what you were looking for though.