Hi,
Before the first days of auto-exposure calculation in cameras (film then),
the
problem has always been to sum all the lights and darks in a potentially
infinite
range of images to determine a single correct exposure. The original solution
that
underlies auto-exposure and all the sophistication of today's cameras is to
assume
that if all areas of the proposed image were mixed together like paint, the
overall
outcome would be an 18% gray.
For decades, Kodak sold 18% gray cards and sheets for photographers to
calibrate their exposures manually, even before "auto" exposure. Even though
they
may be using a $10,000 digital camera, most (probably all) professional
photographers have yards and yards of 18% neutral gray backdrop material. 18%
gray
is the starting point for "correcting" exposure if needed. It will produce the
best
results, just like Anne said, for the reason that the underlying algorithms of
the
camera's electronics are build on that supposition.
Sterling K. Webb
-------------------------------------------------
[EMAIL PROTECTED] wrote:
> And I never use a black background, it just drowns out the specimens. I
> found some file folders in a very soft, neutral shade of gray and I find that
> it
> does not distort the color of whatever pieces you put on it, being a green
> Tatahouine, a very dark Kainsaz or a yellow Libyan glass.
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