RE: filmscanners: RE: filmscanners: RE: filmscanners: Pixels per inch vs DPI

["Austin Franklin" <darkroom@ix.netcom.com>]

Thanks Harvey...but I really don't know what more I can explain...and I
don't know how much more basic I can get...

Sigh.

> -----Original Message-----
> From: owner-filmscanners@halftone.co.uk
> [mailto:owner-filmscanners@halftone.co.uk]On Behalf Of SKID Photography
> Sent: Sunday, October 28, 2001 11:14 PM
> To: filmscanners@halftone.co.uk
> Subject: Re: filmscanners: RE: filmscanners: RE: filmscanners: Pixels
> per inch vs DPI
>
>
> Austin,
> Most of what you are saying in this latest missive was brought up
> before and rejected by Rob.  It was at that
> point that I gave up.  But, kudos to you for your tenacity and
> deep knowledge on this subject.  I feel like
> I've been vindicated, and by someone with far more skill than I.
>
> Harvey Ferdschneider
> partner, SKID Photography, NYC
>
>
>
> Austin Franklin wrote:
>
> > > Austin wrote:
> > > > That's the point, it isn't an argument!  It's like asking
> > > > why the number 9 is larger than the number 4.  It's just
> > > > the way it is.  It's just a fact of simple physics that a
> > > > pixel does not contain near the same amount of information
> > > > as a dye cloud.
> > >
> > > I suspected I should have chosen a word other than
> "argument".  The number
> > > 9 is larger than the number 4 because it is a convention that 9
> > > is 5 integer
> > > values larger than 4.  Other than that, the digit 9 or the
> word "nine" are
> > > simply labels to represent an idea.  Saying "it is because it
> is" does not
> > > constitute any sort of meaningful explanation.
> >
> > Some things just are, and the truth is manifested in and of it self.  A
> > basket that has 25 eggs in it has MORE eggs than a basket with 4, right?
> > All semantics aside.
> >
> > Here is (one of) your original question(s)/statement(s), which
> I have been
> > answering:
> >
> > "> > > I don't see why stochastic or random dye clouds inherently
> > > provides more
> > > > > information than a pixel."
> >
> > The point of contention appears to be "more information".  I believe we
> > agree on what "more" and "information" mean.  Pixels ONLY represent the
> > tonal value of the area which the sensor sees, which does NOT
> represent the
> > physical characteristics of the dye cloud, unless the dye cloud
> is perfectly
> > square and happens to line up perfectly in the field of view of that one
> > pixel.
> >
> > In fact a pixel MAY represent many dye clouds, or only a
> portion of a single
> > dye cloud, but there is NO way you can represent the amount of
> information
> > in a single dye cloud by a single pixel, when A pixel ONLY
> contains tonal
> > information.
> >
> > Dye clouds are irregular in shape, and dye clouds do NOT line
> up 1:1 with
> > pixels.  Even if you did characterize each and every dye cloud
> digitally,
> > you would need more than spot tonal information, You would also
> have to use
> > many pixels, or characterize the shape, because it's irregular.
> > Characterizing the shape will be very consuming (as in a lot of data) to
> > represent.
> >
> > Given all that, I believe it is obvious why a dye cloud
> "provides inherently
> > more information than a pixel".  If you don't see that, I can't
> explain it
> > any further without sitting down at a white board and drawing
> it out step by
> > step...
> >
> > > Claiming that a pixel has anything to do with physics is an
> odd thing to
> > > do.
> >
> > Now that's an odd thing to do...claim a pixel has nothing to do with
> > physics...  I don't know about your scanner, but mine is not Gnostic.
> >
> > > A pixel is a number or a set of numbers that represent a mixture and
> > > intensity of light.  It's not limited by physics.
> >
> > A pixel has an analog to digital origin in our case.  This
> analog to digital
> > conversion has limitations, which ARE limitations of physics.
> That's just a
> > fact.  If you created a drawing with Adobe Illustrator, then your pixels
> > would not have an analog origin.
> >
> > > A dye cloud
> > > has a certain
> > > dimension and a certain behviour with light.  A pixel is not
> limited in
> > > the same way.
> >
> > Er, a pixel is FAR more limited, since it is only representing a single
> > characteristic of a regular patterned point source (as in a
> single element
> > in a regular grid pattern of equal sized elements).
> >
> > > A pixel could represent an area the size of an atom, or the
> > > size of a galaxy; *any* dimension
> >
> > Except for the fact that we are talking about film scanners,
> and the are a
> > pixel can represent is limited by physics...
> >
> > > and it may be an 8 bit number
> > > or you could
> > > pick any number of bits.
> >
> > Yes, and it ONLY represents tonality, NO other characteristic at all is
> > represented by a pixel.
> >
> > > How small would you like to make the
> > > area represented
> > > by the pixel and how many bits of RGB would you like to use until
> > > you exceed
> > > the data contained in a chemical representation of an image?
> >
> > Then you said "it's just a matter of increasing the resolution of the
> > grid..."
> >
> > Which is where the physical characteristics come in play.  There are
> > physical limitations as to how many pixels you can
> "practically" use in a
> > scanning system.  You can't just make a sensor of infinite density (or
> > infinite size and use optics), since these bring up physical
> limitations.
> > These are just facts of physics, and why physics is involved.
> >
> > > I'm
> > > astonished
> > > that you could believe the "fact" you have stated above.
> >
> > Because what I have stated ARE facts.  It would take MANY MANY pixels to
> > represent the physical characteristics of a single dye cloud,
> and one could
> > argue for quite some time what is the "correct" number of pixels to do
> > this...and NO, because of physical limitations on sensor
> element sizes (that
> > are NOT the same as faster processors, larger memory etc...those aren't
> > analog sensors, so advances in those areas are not entirely
> applicable to
> > advances in digital imaging sensors in this case) you can not
> just "increase
> > the resolution of the grid".
>
>
>
>