[filmscanners] Re: film and scanning vs digital photography

["Arthur Entlich" <artistik@shaw.ca>]

I don't disagree with much that you stated.   A good deal of the extra
file size in a scanned silver halide image is just grain artifacts, and
offers no image information.  However, if the same processing that is
done to digital images in camera were done to the film image, a lot of
the grain could be suppressed.

The same thing that makes some of the perceptual problems from digital
output (the grid pattern) also allows for some fancy processing that can
nearly eliminate visible pixels.  For instance soft gradient areas
really shine, like expanses of sky.  The same area in film looks like a
dish of pond water under a microscope. However, that is the same process
the somewhat diminishes apparent resolution in more complex detailed areas.

But this just shows the fact that there is a considerable subjective
aspect to evaluating the results that technical equipment can't
"prove".  Each of us sees random and matrix patterns differently, and
the subject matter also alters how we respond to those artifacts.

Art

David J. Littleboy wrote:

>From: "Arthur Entlich" <artistik@shaw.ca>
>
>
>Film grain itself is not actual information. it is the random structure
>used to create the image on it's smallest level.  Grain occurs in three
>random manners.  Firstly, each color layer is laid down with the silver
>halide grains in a completely chaotic manner.  Secondly, the grain size
>is randomized, and thirdly, the relationship between those factors
>between the layers is randomized, as well.  This creates a "forgiving"
>structure.
><<<<<<<<<<<<<<<<<
>
>Hmm. I don't find it forgiving in the slightest. I strongly dislike have the
>same ugly texture superimposed on all my images, and for prints I will
>actually show people, never use enlargements over 8x.
>
>This means that 35mm is for 8x10, 645 for 12x18, and 6x7 for 16x20.
>
>All of these produce superb quality prints at these sizes. But they wouldn't
>be at sizes larger than that.
>
>Meanwhile, my 5D makes just as good 12x18s as 645 does. So there's no point
>in shooting 35mm or 645 at this point in history.
>
>
>
>Due to the use of the Bayer matrix, the color interpolation required,
>and a number of other factors,  digital images are intentionally blurred
>via electronic filtering.  This is why judicious use of unsharp masking
>can bring so much detail back to an image.
><<<<<<<<<<<<<<
>
>No, it's _physical_ filter in front of the sensor, called a low-pass, or
>antialias, filter. Nothing electronic about it.
>
>The mathematics of discrete sampling tells us that such a filter is required
>to achieve correct imaging up to the mathematical resolution limits of the
>sensor. But you knew that.
>
>What I've recently come to realize is that low-pass filtering _improves_
>resolution by removing jaggies. Just as antialiasing in font display
>improves the apparent resolution of fonts on the screen, antialiasing in
>discrete capture allows the sensor to show the position of sharp edges and
>lines more accurately than happens in non-antiliased cameras.
>
>
>
>The reason the debate regarding image resolution - film versus digital -
>continues, is because instrumentation can't really answer it. Yes,
>numbers of line pairs can be read, etc. but that isn't how we perceive.
><<<<<<<<<<<<<<<<<<<<
>
>So far, so good.
>
>
>
>Our eyes prefer random analogue and in spite of the defects in this
>method, we have built in filters to deal with that because nature is
>designed around random noise.
><<<<<<<<<<<<<<<
>
>Your eyes, maybe. Mine don't like random noise. It's a good thing that film
>scales up to much larger formats than digital. I really don't understand how
>people can stand 5x7s from 35mm Tri-X.
>
>
>
>So, this debate cannot be answered by machines.  It can only be answered
>by human consensus.
><<<<<<<<<<<<<<<<
>
>Yep. And 12x18 images from 24x36mm of film are unacceptable, whatever film
>is used. (And embarrassing if the bloke who made the print displayed next to
>yours used MF or 12MP digital.)
>
>David J. Littleboy
>davidjl@gol.com
>Tokyo, Japan
>
>
>
>
>

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