1) Your negative will be relatively "contrasty" - This is like (but not exactly) N+1
Originally Posted by jsimoespedro
2) Your negative will be relatively "flat" - This is like (but not exactly) N-1
3) This is the definition of "push one stop"
4) This is the definition of "pull one stop"
Push/Pull and N+, N, N- development are different vocabulary used to describe exactly the same thing... But importantly to achieve different goals.
I am oversimplifying to make a dramatization, don't anyone who shoots in the dark take this as a character attack. When you have to shoot in the dark you have to push...
Most people "push" film to get a faster shutter speed in a dark bar, in careless or sloppy shooting conditions under pressure where you can't control light. The idea is to get a negative that you can use from an otherwise hopeless situation.
The Zone System is used to give a negative of a carefully measured and exposed scene, just the right amount of development so that it gives the best quality negative.