Coring, NR1 and NR2
 

Hi:

I am trying to figure out when to use these, I understand they all have an effect on noise reduction, but works differently.

I understand that coring does noise reduction in the dark areas, so the effect of coring is greater when black is set to strech rather than press?

But when would I use coring over NR1 or NR2? Subject in shadow with light background? Or should I combine coring with NR1 or NR2, eg. in lowlight situations?

Secondly, when should I prefer NR1 over NR2? Can I achieve the same noise reduction with NR2 as with NR1? Is NR1 and NR2 simply two ways of doing the same with different side effects?

I understand that both NR1 and NR2 comes with a penalty. From the description NR1 may leave an after image in some situations, while NR2 should soften the image. In what kind of situations do after images appear?

Anyone can explain when I would prefer one of these controls over the others?

Thanks, Erik