On Wed, 8 Aug 2007 05:05:29 -0500, "Don Pyeatt"
wrote:


"Just Plane Noise" wrote in message
m...

This was one of the first passes on Concorde's first visit to EAA, in
1986.
By the way, the photo was very grainy since all I had was a normal
lens, but I found that Paint Shop Pro's digital noise removal too also
does a nice job with analog grain.

"Analog grain". Interesting, what is it?

All film can be described in terms of how grainy it is, and grain is
somewhat analogous to pixels. Slow film (like Kodachrome) wasn't very
grainy at all, while high speed B&W Tri-X was very grainy. The grain
becomes more noticeable as you enlarge, just as digital images become
pixellated when you enlarge them. Because I was using a normal (50 or
55mm lens, I had to crop and enlarge for that Concorde pic (if you
like, I'll post the original print to show how grainy it was).

There's no such thing as "analog grain"--I was just trying to
distinguish it from digital noise. Grain is grain.

(Read on only if you're interested in a technical description from
Wikipedia

"Film grain or granularity is the random optical texture of processed
photographic film due to the presence of small grains of a metallic
silver developed from silver halide that have received enough photons.

Granularity is a numerical quantification of film grain, equal to the
root-mean-square (rms) fluctuations in optical density, measured with
a microdensitometer with a 0.048 mm (48-micrometre) diameter circular
aperture, on a film area that has been exposed and normally developed
to a mean density of 1.0 (that is, it transmits 10% of light incident
on it). Granularity is often quoted "times 1000", so that a film with
granularity 10 means an rms density fluctuation of 0.010 in the
standard aperture area.

When the grains are small, the standard aperture area measures an
average of many grains, so the granularity is small. When the grains
are large, fewer are averaged in the standard area, so there is a
larger random fluctuation, and a higher granularity number.

The standard 0.048 mm aperture size derives from a drill bit used by
an employee of Kodak.

Film grain is often considered an artistic effect, and can be found in
some digital photo manipulation software such as Photoshop as
something that can be added to an image after it is taken.

In digital photography, image noise sometimes appears as a
"grain-like" effect."