JCO pointed out:
> Faster is better in that you can "slow down" fast
> films with simple ND filters IF YOU REALLY NEEDED TO,
> but there is no way to "speed up" slower films in
> such as simple way and without losing quality the
> way push processing does.
Actually, the analog to an ND filter for speeding up
a slow film is to add light. Adding light to speed
up is more difficult than putting an ND filter on to
slow down, of course, because if the extra light isn't
positioned the same as the light you started with,
you wind up changing the picture ... but in a smartass
sense the corresponding technique does exist and is
commonly used. ;-)
-- Glenn, who has not
yet resorted to
hiding a flash strobe
inside a campfire (but
I've thought about it).
