On Sun, 7 Jan 2001, Jan van Wijk wrote:
> Using the better scanners you have about 2700 ppi, wich adds up to
> about 10 mega-pixel. A few can do 4000 ppi (15 mega-pixel),
> high-end drum-scanners can probably do a bit more.
I'm not sure I follow you math here. With a 4000dpi scanner, from a
36x24mm frame, you get an image that is 5669x3779 pixels. That is
roughly 20 Million pixels. Now, the "pixels" in what digital cameras
call "mega pixel" are actually individual R, G *or* B components.
That is, a 6 Mpixel camera has only 6 million sensors, roughly 2
million of each R, G and B: only 2 million "real pixels". The cameras
interpolate the missing components to get the number of pixels they
claim. This accounts for color artifacts in very bright, sharp
highlights, for example.
So that means that a digital camera should have to be about 60 "mega
pixels" to equal the results one can get with fine grain film and a
Polaroid SS4000.
When you take into account film grain, you have to deal with things
like aliasing between the grain and the scanner sampling rate, so the
60 megapixels probably go down to half that or so to get comparable
results.
An additional problem is that people have been looking at film-related
artifacts for about 150 years now. Film grain has become part of a
language, and as such in can be used artistically in a far easier way
than digital-produced artifacts (ie, a grainy photograph is more
acceptable than a pixelated one.)
I'm all for digital of course. As soon as a $100-$200 digital camera
can produce the results a $10 film camera can, I'll jump ship.
j
--
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Juan J. Buhler | FX Animator @ PDI | http://www.crosswinds.net/~jbuhler
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