Archived posting to the Leica Users Group, 2000/08/07

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Subject: Re: [Leica] Shadow boxing
From: John Brownlow <john@pinkheadedbug.com>
Date: Mon, 07 Aug 2000 16:15:46 -0400

on 7/8/00 4:01 pm, Craig Roberts at croberts@zoomtel.com wrote:

> "The flare helps to get to that threshold so it takes slightly less image
> exposure to show up as density." - Ed
> 
> 
> Hmmmm.  Thank you, Ed, but this sounds...almost literally...like smoke and
> mirrors, or a sophisticated practical joke.  I prefer not to think about it
> any longer.  My brain hurts.

Oh, Craig, sit down, take some Advil and listen!

Say it takes 5 units of light to 'activate' a film grain so it can be
developed.

Let's say you're getting 4 units of light in through the contrasty lens, so
the grain doesn't get developed. So no shadow detail there.

In the flarey lens let's say you get 1 unit of flare all over the film. Now
add that to the 4 units coming in as before, you get 5 units. Ergo, you get
shadow detail.

That's the theory and the number mean nothing and the reasons why it might
not work in practice are blindingly obvious even in this little thought
experiment, but the concept is pretty simple.

- -- 
Johnny Deadman

http://www.pinkheadedbug.com

Replies: Reply from Tina Manley <images@InfoAve.Net> (RE: [Leica] Shadow boxing)