Re: [APML] A small print film test...

["Don Westergren" <westergren@netzero.net>]

Bill,

TechPan and the discontinued Kodak Royal Gold 200 both significantly
increased red sensitivity by hypering.  In the case of several other color
negative films, hypering increased the sensitivity to blue and green without
much change to the red (Fuji Superia400, Agfa Optima II 400, Kodak Portra
800).  Hypering can affect sensitivity and/or reciprocity but there is no
general rule that works "across the board" for all films.  Each film reacts
differently to hypering.  Some films react and are improved for our use,
some films get worse, and some films don't react at all. Films like
Supra400, LE400 didn't improve with hypering, while PPF400 and PJ400
improved slightly.  These last four films were all quite usable for astro
pics without hypering.  The old RG400 actually lost light sensitivity when
hypered and was generally only usable unhypered.  The films I mentioned that
show an effect by hypering generally show that effect at both short (1 sec)
and long (better reciprocity) exposures.

A film that shows good red sensitivity to short exposures has a better
chance of working for long exposures, which is what you mentioned you have
experienced.

Don

> My understanding of the hypering process is this. That *if* the film is
> good to begin with it can possibly decrease reciprocity failure to a
> manageable level. Now all of the films that I have shot hypered, were
> good unhypered ..... good reds, blues and greens. Hypering made them
> better. Particularly for long exposures.
>
> Is this, in fact, accurate ? Can anyone point to a relatively current
> film that had horrible red response that hypering improved ?
>
> Unhypered TP is quite useable for short exposures.
>
> T-Max in all the varieties that I have shot had horrible red response.
> Therefore my guess is that hypering will gain nothing. I used this film
> to focus test my prime focus set-up and my schmidt camera. Never saw any
> red in any of it (realising it *is* a B&W film mind you.) :)
>
>
> I guess what I am trying to say is that unless someone can state that my
> assumption is wrong, trying short exposures with the film and
> determining the overall color response makes more sense than hypering a
> bad film to start with. My understanding is that hypering does not
> change the sensitivity at a given wavelength. It just reduces reciprocity.
>
> Regards
>
> Bill
>
> --
>
> William R. Mattil  :  http://www.celestial-images.com
>
>
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