That's right about films but lowering one stop on the camera means exactly
half the light coming in to the film plane.
( I agree that not all films will react exactly the same. )
The question was how can you imitate this in photoshop ?
----- Original Message -----
From: "ADavidhazy" <andpph@xxxxxxxxxxxxxxxxxx>
To: "List for Photo/Imaging Educators - Professionals - Students"
<photoforum@xxxxxxxxxxxxxxxxxxxxxx>
Cc: <andpph@xxxxxxxxxxxxxxx>
Sent: Thursday, September 15, 2005 7:59 PM
Subject: Re: counting stops in Photoshop
"Unfortunatley" (or fortunately depending on your point of view) film is
non-linear in its response and you can't just "up" values willy-nilly.
You'd
have to know which film, its charateristic curve, the placement of the
scene
luminance values along that curve, flare, etc., etc.
It would really be nice if one could do that as the days of under or
overexposure would be gone. Maybe digital shooting RAW? Seems this is a
panacea
for all ills in the modern world.
OK - time for another cup o'java or maybe a nap.
g'day!
andy
