Re: [APML] TechPan Hypering Experiments

[Aplanatic@aol.com]

Hi Jerry,

> Interesting that the unhypered film only showing a 1.2 stop change  in 
>  sensitivity from 15 seconds to 64 minutes.

I also expected it to be quite dead for long exposure times.
  
>  I guess that means it was almost totally dead at 15 seconds to start with.

Either that or the hypering process increases the speed even for short 
exposure times, or some of both.  I don't know.
  
>  I wonder what the change in sensitivity would be from say 1/64th of a 
>  second  to 64 minutes?

I wonder the same thing.  It's very hard for me to compare a short exposure 
to the long ones.  To do so I would need a carefully calibrated exposure 
system over a very wide range of exposure times.  The step density wedge 
method is just not good enough because I run out of range if I try to compare 
very long and very short exposures at the same light level.  The good news is 
that hypered TechPan seems to have essentially no reciprocity failure between 
15 seconds and an hour.  A great astrophoto film, but we knew that already. 
<g>

Dave

--  APML Archives at <http://www.system.missouri.edu/apml/>  ---
                Unsubscribe at <majordomo@seds.org>