Re: Flashing and Bumping

[T3D Eric Goldstein <egoldste@xxxxxx>]

Bill Carter comments:

> I can see no reason for this to be the case. In fact, it is customary to
> have motion picture film flashed at the lab, after exposure. As I recall,
> there's such a thing as a "bump" used in printing. I think this is taken
> with the screen in place, so there may be a certain order of exposure based

and Greg E asks:

>   I was thinking that it wouldn't matter if it was
> before or after. Either way you are getting more light
> in the shadows. But I guess that pre-flash sensitizes
> the film so that it records the shadow detail more
> faithfully than without (ie detailed vs black shadows).
> 
>   Correct?


Warning: I am a shooter, not a technician, and am merely repeating my
best recollection of what DPs and those who have written authoritatively
on the subject have said...

My understanding of a flash, as Greg and Kirk have said, is that you are
"pre-sensitizing" or fogging the toe area of the film and effectively
contracting the contrast range from the bottom up. A "bump" as I recall
is used for screened (halftoned) art work and is a post exposure process
which effects the size of the halftone dots and not their density...
I'll have to reread and reflash(!) my memory...

I don't believe motion picture negatives are flashed after the fact
(there used to be at least one reel of preflashed stock available to the
DP at any given time, and more if broad exteriors which could not be cut
or filled were being shot in harsh light), I think it's the subsequent
print stock (which has a shorter tonal range) which is flashed before
being exposed to the negative... again I need to refresh memory...


Eric G.


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