If I understand your question, I think you misunderstand the concept. Let me explain...
Whenever things get hot enough to put off light, the light they emit is at very specific frequencies. Conversely, if something isn't glowing of it's own according but has light bouncing off of it, portions of the light are absorbed rather than reflected. This too happens at very specific frequencies depending upon what is doing the absorbing. The result is a spectrum of light that is incomplete. It either has emission lines of absorption line depending on whether you talking about emitted or absorbed light spectra. Each element has a very specific set of spectral lines. This is how they know that both the Sun and Jupiter are made of mostly hydrogen and helium.
Red-shift happens when something is moving away from us at a rate sufficient to cause the frequency of the light to be dropped. It's just the same as when the pitch of train horn drops as it moves past and away from you only with light, a drop in pitch is detected by us as a shift toward the red end of the spectrum. The faster the motion away from us, the bigger the red-shift. Likewise, when something is moving toward us, the spectral lines are shifted toward the blue end of the spectrum. This is sometimes called blue-shift but more typically you'll see it refereed to as negative red-shift.
This concept is the foundational idea behind the big bang. It seems everywhere you look, everything appears to be moving away from us. The BBT implies that the further back in time you go, the faster the universe was expanding and since light take a long time to get to us, the further away something is, the more it should be red-shifted because of this increased speed of universal expansion. They, therefore, assume that the more something is red-shifted, the further away it is. Some things are so far distant that their spectra are shifted passed the red and into the infrared. This is why they are in the process of spending billions to send up an infrared space telescope.
The problem with this whole idea is that there are galaxies that have significantly different z values (red-shift is expressed as a value of z) that are physically connected together. In fact, the data would seem to suggest that in at least some cases, red-shift is not an indication of distance at all but rather of age. The EU, of course, believes red-shift to be an electrical phenomenon but then again, they think everything is an electrical phenomenon. I'm not convinced that they are right about the electrical nature of red-shift but I am convinced that it is not a reliable means to determining the distance to objects.
Here's a good video on the whole topic put out by the Thunderbolts Project people...