Wow - read this re: Film versus Digital debate!

[vijay_nebhrajani]

By the way, if your monitor has a contrast ratio of 1000:1 (quite common), and you see the image attached to this post, then the lowest band of alternating light and dark lines has a contrast ratio of 20:1 (2% of 1000:1). 1.6:1 is a much lower contrast ratio, perhaps so low that our eyes would barely resolve 1-2 cpmm at it.

 

Once you appreciate how close the tones are for film to resolve 160 alternating dark and light bands (80 cpmm) every millimeter, you'll appreciate just how much difficulty it creates for trying to resolve it with 2 micron silver specks that are all black.

[vijay_nebhrajani]

Bernie - please don't try to gang up with Daniel against me - he isn't even agreeing with you or quoting your

posts or using any of your points. Scientific debates could do without the politics, please.

 

Calling this farcical is nice, but other than that one observation - that you can't see any gray grains under a

microscope - not one shred of evidence has been presented to show that only silver specks visible at 400x

contribute to tone. Not one problem area of Reichmann's theory has been addressed, much less resolved. You even

refuse to acknowledge the possibility that the very process of observation under a bright field microscope could

be leading you to erroneous observations and erroneous conclusions. I even explained how (dynamic range of eyes,

visual recognition process of the brain etc) only to have it shot down by Daniel as "irrelevant" and that he is

"sick of experiments".

 

Do something constructive please; tell me why the doubts I raise with the observation process are invalid.

Educate me, instead of saying that they are irrelevant. That goes for you too, Daniel. I'm questioning the

validity of your methodology (of observation under a bright field microscope) and pointing out possible issues.

Instead of dismissing my doubts as "irrelevant", could you please address them by saying "I believe that our

observations and methodology is correct because here are the clarifications for your doubts...I believe that my

brain is not tricking me into seeing something because... "

 

You've even questioned whether well known visual mechanisms are a figment of my imagination - Bernie, all you are

doing is displaying ignorance. I have no problem with that - I will patiently try and explain things to you or

anyone else, but I have a problem with ignorance and arrogance.

 

So please stop with the arrogance and please stop acting as a cheerleader for Daniel.

[vijay_nebhrajani]

And where the heck is Rishi to summarize all of this?

[vijay_nebhrajani]

And Rich, I finally brought in diffraction into the mix. You were waiting for it, weren't you?

[vijay_nebhrajani]

And will someone please, please explain to me why, when I want to view a solar eclipse, if I hold up a black, fully exposed film over my eyes does the light get through? Why is that film not perfectly opaque? Not trying to argue anything - just want to know. Actually now that I am trying the experiment in front of me, I can even see the filament of a clear 100W bulb hanging in my room through that film.

[rich_evans]

Vijay - You da man!

 

"....Lets see what happens if that speck is out of focus through that microscope, shall we?. Its edges would be fuzzy, light

would be diffracting around it, and if sufficiently out of focus you'd get a uniform gray tone in its place. Correct? Easily

observable even in Kodak's photos that you posted.

 

That is not how a halftone process works, right? In halftone processes, there are no gray areas between black areas, are

there? Its all black or all white.

 

Now, you can have a gray area between opaque grains because of diffraction from out of focus grains, correct? What is

the mechanism of the diffraction? To spread light out, to attenuate its local intensity, correct?

 

What would happen if you had a silver speck that was really tiny, too tiny to see through your optical microscope, because

the light from the bright field diffracted around it? It would still be there, attenuating the intensity of the light falling on it by a

tiny amount, right, both by diffraction and by absorption? Helping form the "gray" between the black, correct?...."

 

Correct - wow, I'm getting flashbacks of lecture halls and professors with bad overhead projectors (anybody remember

those?)

 

OK - so now we're out of the digital and into the analogue - wave theory.

 

In geometrical optics, it is assumed that light tavels in straight lines - but this is not always true. Assume a beam of light

(any wavelength) passing throught a slit towards a screen. The interaction creates a bright band, wider than the slit with

alternating bright and dark bands appearing on either side of the cental bright band. The band intensity decreases as a

function of the distance from the center. This is DIFFRACTION and is the true limiter of image reproduction.

 

For example, the image of a pin-point of light produced by a lens is not a pin-point but is a somewhat larger patch of light

surrounded by dark and bright rings The diameter, D, of this diffraction disc (to the first dark ring) is: D=1.22(lambda)/sin

(theta) where lambda = wavelength of light and theta = 1/2 the lens angular aperture. The further away from the center, ie

the more 'empty' space around a tiny feature, the 'greyer' it will appear.

 

How does this relate? Resolution is difraction limited, diffraction creates variations in contrast.

 

If two small objects are to be distinguished in an image, their diffraction discs must not overlap more than 1/2 their

diameters. This is what determines the resolving power of a lens.

 

Abbe's theory suggests that microscopic objects act as diffraction gratings and that the angle of diffraction increases with

fineness of detail.

 

So from this we can deduce that the single feature that we are calling a 'grain' must be of sufficient size to be resolved as

black. If it is not of sufficient size, then it will be seen as some shade of grey.

 

Add to this the additional diffraction artifact of the actual ester film base and the gelatin/latex emusion and we've got a

whole different set of equations which will affect how we percieve any optical characteristics of the grains or particles of

grains.

[vijay_nebhrajani]

Daniel: "Where are these gray grains? If they are not observed, then film tone is not created by them. Science

doesn't get much easier than that!"

 

Please find me some gray grains in a ND filter. Go look at an ND filter under a microscope - where are the gray

particles?

 

What you are saying is this: "A halftone process creates tone so if there is tone it must have been created by a

halftone process."

 

Logic doesn't get any more absurd than this.

 

I ask you this: "Is there any mechanism other than the halftone mechanism that could create tone on photographic

film?"

 

You say "No."

 

I say, "What's the proof of that? Could there be an ND filter like process could also be contributing?"

 

You say "No."

 

OK then, I ask you "Why not? What happens to all the light that is absorbed by tiny silver specks?"

 

You say there won't be tiny silver specks in any significant quantity.

 

Then I ask - "Then if I take a very light gray I would have a very few silver specks sprinkled on a vast field of

empty space - now if I take another shade of light gray - just very slightly darker - like 1.6 times darker - and

put these two shades next to each other and take a picture, there should be no differentiation in tone, right?

How can film then resolve these as two separate tones at 80 line pairs per mm?

 

At the scale that you see silver specks (400x), do you see tone? Much less differentiation of two tones that

differ in brightness only by a factor of 1.6?

 

You should, since those 80 cycles per mm will form bands only 6.25 microns wide. In those pictures that show ,

you could fit 10-15 of those bands. Go see that picture you posted with a 10 micron by 10 micron square next to

it. You could almost fit two bands in the side of that square that differed very subtly in tone. How could those

very same silver specks that I see in that very same picture be creating such subtle tonal differences?"

 

Please, I'm tired too. Just answer my this one question.

[vijay_nebhrajani]

Rich: "Abbe's theory suggests that microscopic objects act as diffraction gratings and that the angle of diffraction increases with fineness of detail. "

 

According to Daniel, there are no such things as diffraction gratings. If you ever took 100 nm x 100 nm sized silver specks and placed them on (the intersection points of the lines of) a 400 nm grid, the whole thing would immediately act like a Faraday cage, and be completely opaque. As in no light could pass through. Period. Actually, according to what he said about the wire wool analogy of the silver filaments, the silver specks don't even need to be 100 nm x 100 nm. Even 1 nm x 1 nm silver specks placed on a 400 nm grid will be totally opaque. If you ever could make an object like that, it would shield you even from radiated heat, because infrared wavelengths are longer.

[vijay_nebhrajani]

And would it ever shield you from microwaves! But you wouldn't be able to see your coffee steam, because it would be perfectly opaque to visible light too. Drat.

[danielleetaylor]

<P><i>What would happen if you had a silver speck that was really tiny, too tiny to see through your optical

microscope, because the light from the bright field diffracted around it? It would still be there, attenuating

the intensity of the light falling on it by a tiny amount, right, both by diffraction and by absorption? Helping

form the "gray" between the black, correct?</i></P>

<P></P>

<P>I'm not sure here if you're saying something is too tiny to be seen yet is seen (which is logically absurd, as

I've had to point out 12 dozen times now). Or if you're saying that some tiny things become invisible under a

microscope due to diffraction but still appear in a print. If the latter, find these things in a 60" enlargement

from 35mm. Should be easy if they contribute to tone at all.</P>

<P></P>

<P><i>That is not what I meant - I've clearly said that there would be specks at different stages of growth (see

Rich's SEM micrographs, on the left there is one tiny speck about 100-150 nm in the 102kx magnification image).

Are you implying that that speck, sitting there, is contributing nothing at all to tone in the final print?</i></P>

<P></P>

<P>I'm not implying, I'm stating outright. A 150 nm particle sitting by

itself in clear gelatin is for all practical intents and purposes invisible optically and will exert 0 influence

on tone,

detail, anything. It might as well not be there at all.</P>

<P></P>

<P><i>And its not like the Adams/Reichmann theory can explain everything either. For instance, it can't explain

how film resolves 80 cpmm when the target has a contrast ratio of 1.6:1; something that would be impossible

because it would take too large a film area to form tones that close - meaning that you should only be seeing a

random jumble of silver specks rather than finely differentiated tones at such high cpmm.</i></P>

<P></P>

<P>I have no idea how you came to that conclusion. Nothing from the theory suggests that film should be unable to

resolve 80 lpmm. Though I should point out that most B&W films don't do this well at 1.6:1. Acros hits 60 lpmm,

for example. Many only hit 40-50 lpmm. Most color films also cannot do 80 lpmm, and fall in the 40-60 lpmm range.

Velvia is the well known color exception. Old Tech Pan 25 was a B&W film that could hit 85 lpmm. I'm sure there

are some current B&W films and developer combos which can hit or surpass 80, but to be honest I don't know which

ones off hand.</P>

<P></P>

<P><i>Reichmann's theory predicts that the resolution of silver halide based film will be much less than

chromogenic film - which is dye based, and whose dye clouds "pixels" can represent many tones.</i></P>

<P></P>

<P>In a sense that's exactly what we see. Classic B&W film is only competitive with dye based B&W film because

the final silver deposits in classic B&W can be much smaller than dye clouds. Under your theory classic B&W film

should exhibit much higher resolution than dye based films, if silver deposits can act like dye clouds and be

gray.</P>

<P></P>

<P><i>And why, when we make the "pixels" such that they can take on any tone as in chromogenic or color film do

they still not outresolve silver halide film?</i></P>

<P></P>

<P>We're still in the 5 micron range on DSLR pixels. On a B&W line chart they're not going to out resolve the

highest resolution films which have a much lower average grain size. But on a test chart based on tone...like,

say, a 1.6:1 chart...pixels are much more competitive. Again, something predicted by Reichmann.</P>

<P></P>

<P><i>You have, so far only negated my point of view; you have not enhanced Reichmann's or Adams' one bit by

providing appropriate explanations. In other words, if I go through all your posts, I don't come away with an

iota more of understanding how film works, how tones are formed or how film resolution works than if I read a

hundred lines of a pithy Reichmann article.</i></P>

<P></P>

<P>It's a halftone process. What more do you want me to add? Adams and Reichmann got it right, they don't need me

to add to their works ;-)</P>

<P></P>

<P><i>Please find me some gray grains in a ND filter. Go look at an ND filter under a microscope - where are the

gray particles?</i></P>

<P></P>

<P>What do ND filters have to do with the price of tea in China?</P>

<P></P>

<P><i>What you are saying is this: "A halftone process creates tone so if there is tone it must have been created

by a halftone process."</i></P>

<P></P>

<P>No, what I am saying is that at sufficient magnification we only see opaque grains/grain clumps and clear

film. Therefore tone at smaller scales is a product of the mix of these opaque and clear areas. You are the one

who keeps trying to argue from a purely logical, mental space with no consideration of physical evidence that is

clearly observed,

and observed by multiple people.</P>

<P></P>

<P><i>I ask you this: "Is there any mechanism other than the halftone mechanism that could create tone on

photographic film?"</P>

<P>You say "No."</P>

<P>I say, "What's the proof of that?</i></P>

<P></P>

<P>You want me to prove a negative? No other mechanism is observed to be at play. That is sufficient.</P>

<P></P>

<P><i>"Why not? What happens to all the light that is absorbed by tiny silver specks?"</i></P>

<P></P>

<P>The answer to that question lies within the question ;-)</P>

<P></P>

<P><i>You say there won't be tiny silver specks in any significant quantity.</i></P>

<P></P>

<P>You've said that when silver specks are really tiny, they are gray. (Without proof I might add.) I've pointed

out that if they're the basis for gray tones in prints, they must occur with a frequency and in group sizes that

would make them readily observable, yet we do not observe them.</P>

<P></P>

<P>You've claimed there are silver specks too tiny to be seen that contribute tone to a print. I've pointed out

that if they're too tiny to be seen, they can't contribute tone because if they contribute to tone, they are

seen, and should be even more evident at high magnification.</P>

<P></P>

<P><i>Then I ask - "Then if I take a very light gray I would have a very few silver specks sprinkled on a vast

field of empty space - now if I take another shade of light gray - just very slightly darker - like 1.6 times

darker - and put these two shades next to each other and take a picture, there should be no differentiation in

tone, right?</i></P>

<P></P>

<P>Who told you that description is right? Have you photographed a 1.6:1 contrast test chart and studied the film

under a microscope?</P>

<P></P>

<P><i>At the scale that you see silver specks (400x), do you see tone?</i></P>

<P></P>

<P>No. And that's the whole point!</P>

<P></P>

<P><i>You should, since those 80 cycles per mm will form bands only 6.25 microns wide. In those pictures that

show , you could fit 10-15 of those bands. Go see that picture you posted with a 10 micron by 10 micron square

next to it. You could almost fit two bands in the side of that square that differed very subtly in tone. How

could those very same silver specks that I see in that very same picture be creating such subtle tonal

differences?"</i></P>

<P></P>

<P>Because that's not a photo of a 1.6:1 test chart. Photograph one and you will likely find that the clumps

aren't that large and are more finely distributed with gaps. 6.25 microns wide can pack a pretty wide range of

halftone patterns considering many grains are smaller than 1 micron.</P>

<P></P>

<P>Regarding the sun and a light bulb filament: even fully developed out, film is not a continuous piece of

36x24mm solid silver. There are still spaces, and because there are still spaces, there is still a measurable

optical density.</P>

 

[danielleetaylor]

<P><i>According to Daniel, there are no such things as diffraction gratings.</i></P>

<P></P>

<P>I never said that.</P>

<P></P>

<P><i>If you ever took 100 nm x 100 nm sized silver specks and placed them on (the intersection points of the lines of) a 400 nm grid, the whole thing would immediately act like a Faraday cage, and be completely opaque.</i></P>

<P></P>

<P>I most definetly never said or implied that. (Must you resort to strawmen?)</P>

<P></P>

<P>First, don't confuse the mechanism which makes thin metal in a microwave opaque to microwaves with the inherently opaque to visible light nature of silver. Second, 100 nm particles in a 400 nm grid was <i>your</i> hypothetical, <i>not mine.</i> So don't attribute it to me. Third, I don't think I ever rendered an opinion on whether or not this hypothetical grid would be opaque or not in part because you kept altering the particle size (10 nm, 1 nm), and in part because I don't have a firm reference as to what the minimum particle size is of silver which would be opaque.</P>

<P></P>

<P>Let's leave strawmen out of the discussion, OK?</P>

[markci]

<i>The idea of having to spend so much on an expensive DSLR and spend all that time on the computer is really daunting.</i>

<p>

How do you feel about having to spend far more money on film and processing, and far more time scanning?

[James G. Dainis]

<I>The idea of having to spend so much on an expensive DSLR and spend all that time on the computer is really daunting.</I><P>

 

Just drop the media card off at the lab to have prints made the same as you do with film. People who use film don't have to set up a wet darkroom to use it and people who use digital don't have to set up a dry darkroom to use it. <P>

 

If you don't have your own darkroom, wet or dry, it just means that you are willing to take whatever the lab gives you.

[vijay_nebhrajani]

<i>I'm not sure here if you're saying something is too tiny to be seen yet is seen (which is logically absurd, as

I've had to point out 12 dozen times now). Or if you're saying that some tiny things become invisible under a

microscope due to diffraction but still appear in a print. If the latter, find these things in a 60" enlargement

from 35mm. Should be easy if they contribute to tone at all.</i>

<p>

The latter. You can't find these things at 400x, you're not going to find them at 60x. They would change the

density of the clear part on the enlargement - you'd have black specks on gray, not on white. The base density of

the clear area got increased.

<p>

<i>I'm not implying, I'm stating outright. A 150 nm particle sitting by itself in clear gelatin is for all

practical intents and purposes invisible optically and will exert 0 influence on tone, detail, anything. It might

as well not be there at all.

</i>

<p>

You have heard of retouching dyes for negatives, haven't you? See a retouched portion of the negative at 400x

through that optical microscope, you'll still see black specks on clear. Why you ask? Remember my experiments

about how vision works? Of course, the tonality of retouched parts of negatives changes on the final enlargement.

The paper you print on doesn't care how the light reaching it is attenuated. The light could be attenuated by

those 150nm specks by absorption, by diffraction or by a retouching dye. The final tone will be affected.

<p>

<i>I have no idea how you came to that conclusion. Nothing from the theory suggests that film should be unable to

resolve 80 lpmm. Though I should point out that most B&W films don't do this well at 1.6:1. Acros hits 60 lpmm,

for example. Many only hit 40-50 lpmm. Most color films also cannot do 80 lpmm, and fall in the 40-60 lpmm range.

Velvia is the well known color exception. Old Tech Pan 25 was a B&W film that could hit 85 lpmm. I'm sure there

are some current B&W films and developer combos which can hit or surpass 80, but to be honest I don't know which

ones off hand.

</i><p>

Information theory. A halftone process is a sampled process - you sample a continuous signal. If your sampling

frequency is too low, or your sample too coarse (too large changes in the amplitude of the sample), you can't

reproduce the original signal. Film obviously reproduces the original signal at 80 cpmm (you quoted 50-80 cpmm,

it's your number) for a signal amplitude of 1.6:1. Silver specks are (per your theory) either black or clear. Its

like they can have a value of 1 or 0. That is like single bit sampling - each sample records the difference from

the previous sample, so you have to do it at a much higher frequency than if a single sample could have multiple

values. This is like having 192 kbps or 384 kbps bit rates for 48.1 kHz sampling.

<p>

For reproducing a light intensity wave of such tiny amplitude (1.6:1) and such high frequency (80 cpmm) you need,

per Nyquist's theorem, a sampling frequency of at least 160 cpmm if each sample could have continuous values, or

much higher, say 10x higher (if each sample can only be one bit (clear/opaque) and for a total of 1024 tones = 10

bits per tone. 16 bit tones would need 16x higher sampling rate etc.) or 1600 cpmm . This would translate to

silver specks that would be 300 nm in size. (1000/(2x1600) = 1000/3200 roughly = 300 nm). I don't know about the

accuracy of this calculation, but it is conservative, since we assumed only that the film was capable of 1024

tones. If you increase the number of tones, the speck size has to decrease even more in order to resolve those

finer changes of tone. This last statement should be intuitive to understand. Sort of like if you want to detect

finer changes in tone, either each pixel is capable of more bit depth, or you increase the number of pixels per

unit area.

<p>

As per your statement, this is quite impossible, because silver specks below 400 nm or so will have no effect

whatsoever; so what will happen is aliasing - a process whereby the cpmm information is lost, and the whole thing

turns a single tone. Intuitively, you can't represent subtle changes in tone over a small area with large chunks

of silver. Either the tone changes will be large (like for the case of 1000:1 contrast) or the area will be large

(you'll resolve at 1.6:1 contrast but at lower, like 5-10 cpmm).

<p>

<i>In a sense that's exactly what we see. Classic B&W film is only competitive with dye based B&W film because

the final silver deposits in classic B&W can be much smaller than dye clouds. Under your theory classic B&W film

should exhibit much higher resolution than dye based films, if silver deposits can act like dye clouds and be

gray.</i>

<p>

That is saying that classic B&W would have poorer resolution than dye based B&W film were it not for the fact

that it has higher resolution. Circular. Under my theory the information content is compressed and stored by

silver halide crystals prior to development. These are roughly the same for both dye based and silver based film.

After processing dye clouds are at a slight disadvantage because of somewhat larger size, so chromogenic films

would have somewhat lesser resolution. Evidently you haven't even understood my theory but are sure it is wrong.

<p>

That is dogma.

<p>

<i>We're still in the 5 micron range on DSLR pixels. On a B&W line chart they're not going to out resolve the

highest resolution films which have a much lower average grain size. But on a test chart based on tone...like,

say, a 1.6:1 chart...pixels are much more competitive. Again, something predicted by Reichmann.</i>

<p>

Really? 80 cpmm at 1.6:1 is not competitive? Or 1.6:1 is not based on tone? Or do pixels resolve more than 80

cpmm for that 1.6:1 chart? The fact is pixels don't outperform film even at 1.6:1.

<p>

<i>It's a halftone process. What more do you want me to add? Adams and Reichmann got it right, they don't need me

to add to their works ;-)</i>

<p>

More dogma and circular reasoning. Explain why the halftone process, in clear violation of information theory,

resolves 80 cpmm at 1.6:1. Explain why classic B&W outresolves chromogenic film.

<p>

<i>Please find me some gray grains in a ND filter. Go look at an ND filter under a microscope - where are the

gray particles?</i>

<p>

Once again, you assume that there have to be large gray particles. I clarified that I didn't say that. You

couldn't find those. However, any particle that is small enough will cause diffraction, and will also absorb

light that falls on it, creating a local area where the light intensity will be reduced. If the light intensity

is reduced, it will appear lighter on the print, thereby making tone.

<p>

<i>What do ND filters have to do with the price of tea in China?</i>

<p>

What is the relevance of your question? I invoked ND filters to show you that tone can be changed without the

halftone process. Either you get that, or you don't. And the best teas come from India, not China. Specifically

from Assam and Darjeeling.

<p>

<i>What you are saying is this: "A halftone process creates tone so if there is tone it must have been created by

a halftone process."

<p>

No, what I am saying is that at sufficient magnification we only see opaque grains/grain clumps and clear film.

Therefore tone at smaller scales is a product of the mix of these opaque and clear areas. You are the one who

keeps trying to argue from a purely logical, mental space with no consideration of physical evidence that is

clearly observed, and observed by multiple people.</i>

<p>

You are treating an optical microscope and the visual process of the eye/brain as if it were a precise

densitometer that could record absolute density values. My argument has enough merit. See Rich Evans' post.

Evidently he understands the tone formation process is more complex than a halftone "arrangement of dots"

process. You either don't or can't accept that Adams could have been wrong.

<p>

<i>I ask you this: "Is there any mechanism other than the halftone mechanism that could create tone on

photographic film?"

<p>

You say "No."

<p>

I say, "What's the proof of that?

<p>

You want me to prove a negative? No other mechanism is observed to be at play. That is sufficient.</i>

<p>

Is proving the opposite of a statement any different than proving a statement? What do you mean prove a negative?

No other mechanism is observed? What if the observation methodology is flawed?

<p>

You still haven't given me one explanation about why you think the methodology is not flawed when I pointed out

my doubts. Remove the doubts in my mind - address them.

<p>

<i>"Why not? What happens to all the light that is absorbed by tiny silver specks?"

<p>

The answer to that question lies within the question ;-)</i>

<p>

Cute.

<p>

<i>You've said that when silver specks are really tiny, they are gray. (Without proof I might add.) I've pointed

out that if they're the basis for gray tones in prints, they must occur with a frequency and in group sizes that

would make them readily observable, yet we do not observe them.

<p>

You've claimed there are silver specks too tiny to be seen that contribute tone to a print. I've pointed out that

if they're too tiny to be seen, they can't contribute tone because if they contribute to tone, they are seen, and

should be even more evident at high magnification.

</i>

<p>

They are too tiny to be seen as individual specks (at any magnification), but their effect is readily observed on

a print - attenuation of light, change of tone on print. Their effect is not easily observed through a 400x

bright field microscope, and I've explained why. You do see gray areas through the microscope and on the Kodak

images too. Try figuring out what they are and how that works.

<p>

<i>Who told you that description is right? Have you photographed a 1.6:1 contrast test chart and studied the film

under a microscope?</i><p>

Your/Adams'/Reichmanns theory requires that. Don't you understand your own theory? And no to the second question.

I haven't photographed a 1.6:1 chart.

<p>

<i>At the scale that you see silver specks (400x), do you see tone?

<p>

No. And that's the whole point!

</i><p>

OK, you won't see tone.

<p>

<i>Because that's not a photo of a 1.6:1 test chart. Photograph one and you will likely find that the clumps

aren't that large and are more finely distributed with gaps. 6.25 microns wide can pack a pretty wide range of

halftone patterns considering many grains are smaller than 1 micron.</i>

<p>

OK, so you will see tone.

<p>

Make up your mind, will you?

<p>

<i>Regarding the sun and a light bulb filament: even fully developed out, film is not a continuous piece of

36x24mm solid silver. There are still spaces, and because there are still spaces, there is still a measurable

optical density.</i>

<p>

But how can there be spaces? Silver is opaque, and I can expose the film to 10 minutes in the sun to get max

density, and there'd be overlapping opaque specks of silver in the entire thickness of the emulsion - besides, I

don't see any spaces under a 400x microscope. Heck, I don't see spaces in the darkest areas of the 400x images

you posted. The gray is just out of focus grains. And OK then, let me take two pieces of film back to back. Drat.

I still see the sun.

[michael_kuhne]

But James, I do not know about your area. But in my area, especially if I drop off a roll of film for 2-day processing service, I get a better price for the sets of 5x7 prints using film than I do with digital prints. Especially if I order multiple sets, like 3 or 4 sets, which I often do. And I can get a digital cd made of the roll as well, at very low extra cost.

 

I am sticking with my position that digital and film are tools, each having advantages for certain uses.

 

For instance, in September I went to a big outdoor auto show with friends. I had three sets made to supply prints to my friends to put into a photo album. The cost per print for those 75 5x7 prints per roll is lower than I can find for prints from digital. If I get a cd made, I can just pop that into my pc to look on screen or e-mail, etc. Very low-cost, high quality, satisfactory and effective with my nearby stores.

 

I also often shoot competitive high school and college wrestling. Likewise, I get 3 sets made for the coaches, the athletes, and their families. Film is more cost effective as long as my success rate for keepers is very high, which it is.

 

If there is an occasional shot I want to apply alterations through digital darkroom, and I did not get a cd made, I have my film scanner.

 

For really wide, wide-angle shooting I often turn to film, especially for low-light and/or needing very low distortion. I have a fine Sigma 24mm f/1.8 EX DG lens I like. Fast. Low distortion. It is still wide angle like 35mm when put on a DSLR, but not nearly as wide. Getting into a FF DSLR is looking at a lot of $$$ compared to a film SLR, which I already have anyway. You cannot get a f/1.8 prime lens with this FOV, for an aps size DSLR. If you could, it would probably have higher distortion, be much larger, and cost a lot more $$$. I also have a 20-35mm wide angle zoom lens with far less distortion at the wide end than any 12-24mm DSLR lens, yet it cost less.

 

For loooong exposure shooting, many photographers turn to film, because grain/noise does not increase with long exposure time.

 

For faster-moving sports like roller blade or ice hockey, I have found the keeper rate is MUCH lower. With digital, I find I can just delete the non-keepers, printing only the better shots, and this comes out better. So with fast action shooting, or other kinds of shooting, where there will be relatively fewer keepers, digital is far more practical. Same when only a few shots will be taken at an event. Instead of using say 1/4 of a roll, digital is a far better way to go.

 

Upon my September vacation, I took both film and digital bodies. Both were useful on this particular trip.

[bernardwest]

Shees... I go have a sleep and what do I come back to... more essays to wade through. I'll see if I can (quickly)

touch on a few points:<p>

 

<i>Bernie - please don't try to gang up with Daniel against me - he isn't even agreeing with you or quoting your posts

or using any of your points. Scientific debates could do without the politics, please.</i><p>

 

Is this all you've got left? The 'wounded bear' line. Poor Vijay... we are ganging up on him. Vijay, it's got nothing to

do with ganging up. It's got to do with what I believe. And what I believe happens to mesh pretty well with what

Daniel and Rishi believe (and where the hell is Rishi? Maybe his brain exploded from thinking too much...). Shees

man, you're the only one arguing your point of view (which isn't really a point of view, it's actually just an anti-thetical

position). That's why it might <i>seem</i> like we are ganging up on you. It's not actually us ganging up, it's you

being deserted by your former supporters. And by the way, I don't need Daniel's or anyone elses confirmation of my

reasoning. The fact I mention him is that due to my downgraded role in this thread I am more than happy for him to

take my arguments further, if he likes. <p>

 

<i>What would happen if you had a silver speck that was really tiny, too tiny to see through your optical microscope,

because the light from the bright field diffracted around it? It would still be there, attenuating the intensity of the light

falling on it by a tiny amount, right, both by diffraction and by absorption? Helping form the "gray" between the black,

correct? <p>

 

If that is not the formation of tone, what is? </i><p>

 

This, to me, is a non-sensical. You are saying that tone is now formed by "diffraction". I can't see how diffraction

patterns can represent the image that is projected onto the film. Diffraction patterns are hardly linearly related to

light intensity and developing time. For example, let's assume either of the two competing hypotheses (binary & non-

binary grains): In both cases it will be possible for tiny specks to recieve enough exposure to go fully opaque.

Right? That is, they will impart a fully black tone onto the negative and print. But you are saying that diffraction will

happen around these tiny specks, and that the result will be a grey tone. See the contradiction? You've got a speck

(s) that should be black, but which is actually represented by a grey tone (under your line of reasoning). Clearly, in

your diffraction hypothesis, exposure isn't related to tone.<p>

 

<i>In other words, if I go through all your posts, I don't come away with an iota more of understanding how film

works, how tones are formed or how film resolution works than if I read a hundred lines of a pithy Reichmann article.

<p></i>

 

Rubbish. Reflect this little gem back onto youself and tell us what you see.<p><i>

 

I have done my bit of this by providing a theory</i><p>

 

WHAT THEORY? All you've done is poo-poo ours.<p>

 

<i>Educate me, instead of saying that they are irrelevant.</i><p>

 

They're not mutually exclusive, you know. We ARE educating you by telling you that the dynamic range of the

eye/brain is not relevant and by explaining that a microscope doesn't exceed the dynamic range of the eye/brain,

otherwise it would be not possible to see grey 'stuff' of any type under a microscope (which you yourself have stated

CAN be seen under a microscope).<p>

[rich_evans]

Bernie - did you not read my last post?

 

Vijay makes valid points re: refraction and grey perception (note: PERCEPTION).

 

Most - if not all - of the individual grains that are in some way contributing to overall smoothness of tone, ie. grey, are too small NOT to be an artifact of diffraction. Diffraction causes a grey 'halo' by definition - see Abbe's diffraction theory. "Developing time" has no bearing on this discussion.

 

Sheesh - its all there in the literature.

 

Rich

[bernardwest]

Rich, Vijay is trying to show how there can be grey toned specks in a negative. From what I can gather, he is trying to say that if we accept the binary grain hypothesis, there would still be grey toned specks in the negative via diffraction. But whether he is or isn't talking about the binary grain hypothesis, diffraction can't represent <b>accurate</b> tonal rendition, as it is totally unrelated to the development process, and is not linearly related (I would believe) to the amount of exposure (light) a grain recieved. So how can it meaningfully contribute to accurate tonal rendition if it isn't directly related to the photographic process from exposure through to print? It's kinda like saying dust on the negative during the printing process contribute grey tones to the print. Sure, it does, but it has nothing to do with the scene that was projected on to the negative at exposure time.

[vijay_nebhrajani]

OK, how about this?

<p>

Say there were a film whose silver halide crystals were 50 nm in size. We all agree that the silver specks that

these crystals would form could never exceed 50 nm, right. After all, they are isolated from each other by gelatin.

<p>

Let's say we expose this film to hours of bright sun - to make sure that all the silver halide has converted to

silver. And then develop it.

<p>

Now this film would either be

<p>

A) Completely clear, per Daniel/Adams/Reichmann; because those 50 nm specks of silver aren't visible through a

microscope; and they can't contribute in any significant measure to tone.

<p>

B) Completely opaque, per Daniel/Adams/Reichmann; because those 50 nm specks of silver would be so closely packed

together, that like a Faraday cage, they would block all light and be perfectly opaque. As in you couldn't see

the sun through it if you held it up to your eyes.

<p>

Daniel's arguments don't make it clear which of A) or B) above will happen, but we can be sure that a film like

this (with 50 nm crystals) would not be able to form any kind of tones, right? Much less fine, really subtly

differentiated tones, right?

<p>

OK then. Take a look at this: <a

href="http://www.konicaminolta.com/about/research/core_technology/material/silver.html">50 nm grain film</a>.

<p>

Not only does such a film exist, it is an X-Ray film that has to produce really fine visual tonal differences,

because heaven forbid, a small spot on the film be misdiagnosed as a tumor...

<p>

Now you have both - a reductio ad absurdum proof - because if A) happens, B) violates the theory, and if B)

happens, A) violates the theory - and <b>physical proof</b>.

<p>

At this point, Bernie and Daniel should accept that their theories are false and agree that Reichmann and Adams

are both

mistaken.

[bernardwest]

Good to see you are at least trying to back up some of your statements with proof. Though I'm not sure about this one. Isn't this film for x-ray imaging? I am assuming this means that it is exposed with x-rays. If this is the case, i'm not sure how this relates to the visible spectrum. X-rays are far shorter wavelengths than light, and can presumable image stuff a lot smaller than light. So you'll have to explain further how this affects the issues related with light photography.<p>

 

<i>Now this film would either be <p>

 

A) Completely clear, per Daniel/Adams/Reichmann; because those 50 nm specks of silver aren't visible through a microscope; and they can't contribute in any significant measure to tone. <p>

 

B) Completely opaque, per Daniel/Adams/Reichmann; because those 50 nm specks of silver would be so closely packed together, that like a Faraday cage, they would block all light and be perfectly opaque. As in you couldn't see the sun through it if you held it up to your eyes.</i><p>

 

I'm not following here. I would expect that either of these could be possible, depending on the density of crystals. If the crystals are sparse, and you couldn't see them under a microscope, how could they contribute to tone in the final print? If the crystals are packed enough, at some point the gaps between the crystals will be too small for light to pass through, and then you'd imagine it would block light out. What am I missing here?

[darrengold]

It terrifies me to get involved in this thread, but having read as much as I can of both sides of the argument can actually see how both sides of the coin are in fact correct.

 

Have a look out of your nearest window at two trees of the same species next to each other. They do however look pretty different. Different tones of green and shadow all made from leaves and light. Imagine the leaves are grain. They are either there or not there. Pretty much the same size and shape as each other. They are not absolutely opaque nor transparent - that depends on the light falling on them.

 

However, like film they are three dimensional. You can't see every leaf contributing to the final image due to their relative depth within the tree, their orientation as you view them, how many overlie each other and again the light that shines on them. Look at any two leaves side by side in two dimensions and they look pretty much the same. Difficult to imagine how they could create so many different tones, hues and shadows.

 

Its because they, and their arrangement within the tree is three dimensional. Just like the grain in the film.

 

There or not there, with infinitessimally small differences between them that in themselves are unlikely to contribute as much to the final image, but with an infinite possibility for three dimensional arrangement and with the ability to vary how it is lit and viewed, significantly contributing to the appearance of the final image.

 

So IMHO:

 

Grain as grain - binary

 

Grain as film, because its 3-dimensional - analogue

[vijay_nebhrajani]

Did you forget what your argument or theory was already? Because I just disproved it.

 

Read my post carefully. I already said you'd exposed that film to sunlight for hours. Would it be black or clear?

 

And X-rays have nothing to do with you viewing an image with your own two eyes once the film has been processed

and delivered to you in a manila envelope. It's a black and white negative image formed with silver specks that

are individually no larger than 50 nm. Get it?

[bernardwest]

<i>Read my post carefully. I already said you'd exposed that film to sunlight for hours. Would it be black or clear? </i><p>

 

I'll answer the same way I did before. It depends on how dense the grains are on the film. The more dense they become, the less 'holes' there are for light to get through. Hence it should become opaque eventually. If there were only a few million of the things on the film, equally distributed more or less, then the gaps between them are too big to block light. So what sort of density of these things are you talking about, and how does this relate to the discussion?<p>

 

<i>And X-rays have nothing to do with you viewing an image with your own two eyes once the film has been processed and delivered to you in a manila envelope. It's a black and white negative image formed with silver specks that are individually no larger than 50 nm</i><p>

 

Presumably they are close enough together (ie. they form clumps) which block light/x-rays. The same as larger crystals do in film. What's wrong with this idea?

[vijay_nebhrajani]

X ray film is sensitive to visible light as well, so if you exposed it to sunlight for hours and developed it,

all silver halide would get converted to silver. That is doubtless.

<p>

So, once again, would the film be clear or opaque?

<p>

<i>Bernie: "What's wrong with this idea?"</i>

<p>

Dude, did you not understand <i>what</i> you were trying to argue? If you took that processed X ray film to a

400x microscope, you would <b>not see any silver specks AT ALL.</b> They could not exceed 50 nm in size and your

400x optical microscope can't resolve them. Hence as per what <i>you</i> asserted throughout this argument, they

couldn't affect tone at all. What clumps formed by what silver? <b>They are all invisible according to you.</b>

Or were you just agreeing with Daniel (or Ansel Adams, or Michael Reichmann) without understanding <i>what</i>

they were saying?

[bernardwest]

Vijay... I've tried answering your A) or B) query, but there is insufficient information to form a proper response. I don't know how to put it any other way. Until I know the density of the crystals/specks on the film, I can't answer. What don't you get about this concept?<p>

 

<i>What clumps formed by what silver? They are all invisible according to you.</i><p>

 

I don't know how this debate can advance any further. You seem to have got yourself so bogged down in hypothetical scenarios that you can't seem to think clearly. They are only invisible while they are smaller than what can be imaged using light. When you clump enough of them together, they reach the size threshold of what becomes visible, and from that point on they are visible. It's like atoms. They are invisible to light imaging, right? But that doesn't stop them becoming visible when enough of them clump together. Why is this so hard to understand. If you can't get past this basic concept, then there isn't much point going on.