If i am adding effects to DV footage, how do i know which colors i can and cant use, ie black that is too dark so it clips

This is only important if your clip is going to be broadcasted.
Most TV stations should be able to fix your signal if it is wrong,
as well.

Most NLE's come with a clip filter or an indication on a histogram
to see when you are going outside the safe area.

If i use the wrong colors, color that isnt in the dv spectrum it is gonna show the effecst looking amateurish.
I know this because scott billups mentions it in his book. But what colors can i use?

Some NLE's will let you correct your colours to broadcast legal automatically (Avid, Premiere...)

Robin.