Thanks all,
I understand that one might alter the filtration for each individual neg, but does not colour neg record its image in basically the same way as reversal film? my point being that we are unable to effect any post exposure changes to reversal film (and we still get good results!). I guess what I'm trying to say in a very roundabout way is: can one apply a single filtration to a whole film or is altering the filtration an absolute necessity and not just an aesthetic exercise (a bit of tweaking at the edges, if you like!). Before anyone jumps on me, I must add that I'm an advocate of neither method; it's just a rogue thought that keeps popping into my head at inopportune moments and keeping me awake at work. Regards, BLIGHTY