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Re: [OM] Nope, It missed it by few hundred miles (intermediate gray)

Subject: Re: [OM] Nope, It missed it by few hundred miles (intermediate gray)
From: Joe Gwinn <joegwinn@xxxxxxxxxxx>
Date: Tue, 23 Sep 2003 22:01:44 -0400
At 12:38 PM +0000 9/23/03, olympus-digest wrote:
>Date: Tue, 23 Sep 2003 07:33:48 +0100
>From: "Julian Davies" <julian_davies@xxxxxxxxxxxxxx>
>Subject: Re: [OM] Nope, It missed it by few hundred miles
>
>And apart from fog, how would you like to describe "some intermediate shade
>of grey", containing, as we have shown, no photographic detail of itself,
>but underlying the details which are resolved?
>I'm open to other terminology here:-)

If the white and black bars are of equal width, then they will smear out to 50 
0ray, which looks pretty dark to the eye.  As I mentioned, this can be seen 
with the Mark I eyeball; no fancy equipment is needed.

If you have access to a laser printer, you can try this out for yourself.  Just 
make up an image containing finw black bars spaced such that the space between 
is the same width.  As you get farther away, eventually you no longer can see 
the individual bars, and the area will look gray.  There is no magic or 
high-tech here.

Joe Gwinn


>Julian
>
> > > >  from:    Joe Gwinn <joegwinn@xxxxxxxxxxx>
> > > >  date:    Mon, 22 Sep 2003 01:55:40
> > > >  to:      olympus@xxxxxxxxxxxxxxx
> > Yes, it all does.  Or, more precisely, the same fraction hits the grains
>as always.  If the spatial frequency is too high (the bars of light and dark
>are too narrow and too closely spaced), the spatial modulation (those bars)
>simply averages out to some intermediate shade of gray.  Nothing is lost,
>nothing is gained.  It's just smeared out.  The human eye does exactly the
>same thing, for exactly the same reason.  If we look at a fine pattern on
>some cloth, from a distance we see the average color, but up close we can
>see the pattern.


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