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[OM] Re: Digital vs. Film discussions

Subject: [OM] Re: Digital vs. Film discussions
From: W Shumaker <om4t@xxxxxxxx>
Date: Tue, 17 Aug 2004 19:54:09 -0400
At 10:40 AM 8/17/2004, you wrote:

>Because by the time you print, they're the proper 360dpi.  Photoshop CS 
>can't create pixels, but it can use some pretty sophisticated math to 
>predict them.

The print software is simply doing interpolation, which helps the
printing process disperse the dots of ink on the paper. But the
interpolation that is happening is not enlarging the picture. Rather it
is just smoothing the square pixel boundaries. The interpolation that
happens does not add detail that allows for a larger print size. It
only smooths the existing edges of the pixels themselves. If you look
at lines/mm nothing changes. Sampling has a limited frequency response
and nothing can improve it unless it is creating fictitious data. the
converging lines on a resolution chart that blur into gray cannot
become lines again? Making crisp edges from blurry ones gives the
impression of sharpness. To some degree you can say it pulls out
information, but that information has to be there in the first place,
and it is frequency limited by sampling. I think it is more a matter of
the way we perceive. Crisp edges feel sharper so we percieve the image
to be sharper. For example, why do some more grainy films seem sharper
than some finer grain films? Is there more information, or is it a
visual phenomon?

A friend of mine has a 256x256 watch camera. He has made some
interesting pictures with it, even though it is only a 0.0625
megapixels (yes zero.zero-six). It is our minds that are good at
predicting visual information. Now that is sophisticated math.

\A/yne


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