Re: [APML] Hypered film effective duration

[steve banbury <banburys@sonic.net>]

Say Herm--any advantage to cooling or purging once the film has been rolled back into the cannister for the drive home?

Steve

Herm wrote:

> "Joseph/Leslie Schaefer" <schaefer@htva.net>  wrote:
>
> > My question is how long after hypering can the film be used before it loses its effectiveness?
>
> Color film, if kept packed with some desiccant granules and double bagged in the
> fridge about 1 month.. Techpan about 1 year frozen..
>
> > Also if I had a large enough tank can the camera be put back into a chamber/tank and effectively >re-hyper the film without affecting the exposures already taken?
>
> You cant re-hyper film, it will ruin it..
>
> > I have also been following some treads about using dry air to purge the camera
> > during exposures. Does the film need to be hypered to benefit from dry air
> purge?
>
> Normal film needs it too, during a long exposure (20 mins and up) film will
> absorb moisture and expand... stars in one corner of the frame will appear
> trailed.. also film sensitivity may go down with high humidity.
>
> Herm
> Astropics http://home.att.net/~hermperez
>
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