Don't take my word as gospel here... From my own experience even shellac labeled as clear will have a bit of color to it. I am under the impression that de-waxing is a process used to make the shellac clearer. If you are looking to darken your bars, then I would use something with a a bit of color in it.

Here is my bike. I used Newbaums red tape and 3 coats of bullseye clear shellac. It did make the tape darker, actually darker than I wanted (wanted to match the seat tube stripes)


Here is another bike of mine. This tape started out white and I added three coats of the same bullseye clear shellac. You can see how much color it actually contains.