Re: [Leica] Early Summitar

["Joe Stephenson" <joeleica@email.msn.com>]

Not at all in left field, Dan. ANsel Adams described and used flahsing, or
preexposure. He did it in the camera by taking "picture" of a white card (or
through a translucent screen) at a very low exposure. Typiclly, he even made
a gadget to use in flashing his film. The technique is very old, and was
needed more in the early days when films did not have the latitude of modern
film.
Joe Stephenson
- -----Original Message-----
From: Dan Post <dwpost@email.msn.com>
To: leica-users@mejac.palo-alto.ca.us <leica-users@mejac.palo-alto.ca.us>
Date: Friday, November 13, 1998 8:47 PM
Subject: Re: [Leica] Early Summitar


>Walter-
>Your story brought back memories- the idea of flashing film . The theory
>behind that is that film has a threshold at the toe- no density at all
until
>that point is reached- I believe it is called the 'Speed Point' because the
>amount of light to attain that point on the 'toe of the DlogE curve
>determined the film speed. If you gave the film just enough exposure to get
>it to reach that 'speed point' then any additional exposure would help
bring
>up the shadow detail! Tricky business- we used a dark green safelight at
>about 4 feet for a few seconds- then re-spooled it!
> We used to 'flash our Tri-X when I was in high school so we could
>photograph the night football games with the flashes we had available in
>1965! We also tried fuming the film in ammonia fumes to make it more
>sensitive, but that didn't work out too well.
>It's refreshing to know we weren't totally out in left field then!
>Dan
>dwpost@msn.com
>
>