Digital BW, The Print

Anthony,

> > Well, if it's just such a fact, then, surely,
> > there are many sources you can provide.
>
> Yes, there are.

And those sources are....???

> > Without proper corroboration to your claim,
> > your claim has no basis in reality, at least
> > as you have stated it.
>
> Your logic is flawed.  The availability or unavailability of corroboration
> for an assertion is independent of its objective validity; you
> cannot assume
> that an assertion is without basis in reality in the absence of
> corroboration, just as you cannot assume that it is based upon
> reality with
> corroboration.

No, with most people that's true, but I know that you sometimes like to make
claims that simply are not correct, claiming they are, and you've been shown
many times to be simply wrong.  I believe that if you simply can't provide
corroboration, which you claim easily exists, but suspiciously fail to
provide it, you're mistaken in what your espousing.

> > One can use one's own observation to corroborate
> > that fact, so your example does not apply.
>
> Really?  How does one determine the direction east through one's own
> observation?

East is simply a universal standard (well, for most people), and most people
know what direction East is...and when it's morning...  Ever hear of
a....compass???

> > That clarifies your statement, and as I said,
> > you can not extrapolate 6M pixels based on that.
>
> Because you say so?

Because I KNOW so.

> > It's simply so easy to refute your claim based on a
> > simple inkjet print.  A 13 x 19 inkjet print at 720
> > DPI has 128,044,800 dots...what ever you want to call
> > them.  I know that they are dithered, but the resolution
> > of they eye can still pick up very small detail in such a
> > print, so let's even say that 300 PPI for a
> > non-dithered image, at 13 x 19 is 22,230,000...and
> > I don't now about you, but I have an entire wall of 13 x
> > 19 images that I can scan across and not move from my
> > spot.
>
> I have no idea what you are trying to say here.

Yes, I know...because it shows that your assertion is flawed.

> The resolving power of the human eye is limited to 30 seconds of
> arc, under
> the best conditions conceivable.  Details of this size cover just one cone
> cell in the retina.  Details smaller than this cannot be
> distinguished from
> one another, and so any level of detail exceeding this level is
> unnecessary
> for visual presentation.

I understand that.  That does not make your assertion valid though.

> > Additionally, it's required to have MORE resolution
> > than the human eye can discretely discern in order
> > to have smooth transitions between changes in
> > tones.
>
> No, it is not.

Well, yes it is.  Any transition that appears smooth is simply of higher
resolution (in one or two dimensions) than you can discern.  The fact is,
you CAN discern that smoothness.

> > You simply can not claim that the eye only has
> > 6M equivalent, since you don't know over how
> > large an area.
>
> But I do, and I've explained that several times.  The area is that of an
> image viewed from a distance roughly equal to its diagonal, e.g., a
> 10x10-inch image viewed from 14 inches.

So what?  That doesn't define the field of vision of a human.  As I said,
your premise is simply flawed.  If the eye can only discern, at high
resolution, a 1" circle, then why are you limiting the FOV to 10" x10" ?  I
can scan MUCH more than a space 10" x 10".

> > For a 5x7 print, possibly...but for something
> > larger than an 8x10 or 11x14, that's simply not true.
>
> For constant proportional viewing distance, it is always true, no
> matter how
> large the print.

You obviously don't get it, and are missing why what you say is wrong.  You
are taking the human eye's ability to have a particular resolution over a
VERY small arc, and extrapolating it to 10 x 10, and the problem is, you
have to SCAN over that 10x10 area to even see the entire 10x10 area at the
higher resolution.  Why are you limiting the area and claiming that's the
limit of human vision?  That's completely unscientific and, well, silly.

> > I disagree with that.  Have you ever looked at a mural?
>
> I've done better.  I've read the physiology texts.  Dissection of
> the retina
> is a pretty good way to determine absolute limits on resolution.

Yes, it is...but that has nothing to do with your claim.  The physiology
text gives the resolution for a VERY SMALL area, and you are extrapolating
that out to some arbitrary area.  That's simply bad science, and of course,
causes you to draw a flawed conclusion.

> > Oh?  How big is the image?
>
> I'll repeat this again:  The image is viewed from a distance roughly equal
> to its diagonal.

Why?  Who determined that as the "limit"?

> In that position, the angular area it subtends needs to
> contain 6-8 million pixels in order to match the visual acuity of human
> vision.

That is not what you initially said.  You said that 6M pixels WAS THE limit
of human vision, and I said it is not, and it simply is not.  You didn't
qualify it with a particular area.

Here was your original claim:

"That's how we
know that 6-8 megapixels is all that anyone ever needs for a full-frame
image (even with perfect vision, it's not possible to see much more than
that)."

What defines a "full frame image"?

  Just about anything beyond that is wasted; anything
> below that may
> show a lack of detail to those with reasonably keen vision.

Why?

> > Er, no, that's really a different issue.
>
> No, it's not.  Depth of field exists only because human visual acuity is
> finite.  There is no such thing as DOF independent of human vision; in the
> objective world outside of humanity, the only part of an image that is
> actually in focus is the part falling on the plane of focus for a
> given lens
> setting.

I understand all that, but that doesn't negate my disagreement with your
statements.

> > Well, I simply know that to not be true, again,
> > it depends on what size the image is.
>
> I've already explained image size often enough.  Please refer to
> any one of
> my previous explanations.

But why are you limiting this to "image size", what on earth does that have
to do with how the eye works?  Are we only limited to looking at fixed
"image sizes"?  No, simply not.  We STILL have to scan an image, no matter
what size it is, providing it's larger than the high resolution are of the
eye, that is.

> > It's an old tactic of yours when cornered...YOU made
> > the claim, so YOU must provide substantiation
> > to it.
>
> I'm under no obligation to substantiate anything.

Yes you are.  You made a claim, and it's your obligation to substantiate it.
Obviously, you can't, or you would.

> > You're missing the point.
>
> You're not making a point.

I am, you're just not understanding it.

Austin