Wow - read this re: Film versus Digital debate!

bernardwest · November 16, 2008

But practically does it make any tones when viewed from a distance? I doubt it. I think that, macroscopically, it's

the halftone process that makes tones.

Undoubtedly so. If only Vijay would let go of his obsession with binary or non-binary grains, he would undoubtedly

agree as well. Infact, he already has (see my last post). This has been the problem with this discussion. You, DLT

and I have been discussing film resolution vs. digital resolution. Vijay has been wanting to (and somewhat

successfully dragging us down to his level with him) discuss freakin' binary or non-binary grains. We've all tried to

repeatedly state it almost certainly doesn't matter that much (if at all, I maintain), but he insists on carrying on about

it. If only we could get him to actually state that he agrees that tonal resolution is dependant on groupings of grains

(which he has implicitly already anyway), then we could all have a congenial discussion about whether grains are

binary or not, INDEPENDANT of resolution.

benny_spinoza · November 16, 2008

I was up to around post 300, but then I had to go on a business trip. Now that I'm back home, I've got more than 200 posts to get caught up on. Could everyone please not submit any more posts for the next couple of days or so until I get caught up? When I get caught up, I'll let everyone know by sending up a big smoke signal from somewhere in southern California.

thanks...

vijay_nebhrajani · November 16, 2008

I don't think there's any argument left at this point Bernie, except perhaps a (redundant) post mortem.

Of course you need many particles to form tone that humans can see with our naked eyes.

Daniel categorically stated that particles below a certain size, no matter how many of them you take

together, could never contribute to the formation of tone that we could perceive. If you disagree, you

disagree with Daniel, not with me.

I was merely disproving that with the pigment particle explanation. In a pigment, particles are below that

certain size that Daniel postulated, yet they form tone.

My point was that even if an individual particle is invisible to the naked eye, it contributes to tone. Its

contribution maybe say 0.0000001% so if you take a billion of them you get tone.

Daniel's point was that its contribution was 0% - which means you could take quadrillions of them

and still couldn't form tone. After all 0 multiplied by any number is also 0.

Similarly Daniel's point was that a silver speck, no matter how small would always be opaque, i.e., absorb

100% of the light that fell on it (and passed 0%). The whole diamond/thin film/sputter coat thing was to disprove

this - my point being that for a small enough silver speck, light would pass through

the silver itself. Of course when light passes through something, that thing is not opaque.

Daniel said that light couldn't pass through a gap that was smaller than the wavelength of that light - and by

invoking diamonds, I pointed out that interatomic gap between the carbon atoms that make up diamond is many

orders of magnitude smaller than the gap Daniel suggested, yet diamond passes all light that enters - i.e., it is

transparent; i.e., in contradiction to Daniel's statement. I don't remember who you disagreed with about this.

Bernie: "It doesn't matter if an individual particle is opaque, clear or some stage in between."

It absolutely does from the viewpoint of resolution. This was the entire thrust of Reichmann's argument -

that silver specks are either clear or opaque (binary) but digital pixels are analog. Based on that he made some

comments about resolution, how many "grains" it would take to get the same number of tones as digital etc.

Again, if the particle is either clear or opaque, a different set of resolution numbers result (artificially

low); whereas if the particle could be in between, a different set of resolution numbers result. This may not

bother you at all, but to those of us who want to do some resolution calculations, it is crucial. Hence such a

long winded debate. Perhaps you missed this subtle but important point.

Bernie: "Welcome to the real world Vijay!"

Where do you think I have been all this time?

You seem to imply that I changed my point of view (hence the welcome), yet the reality is that I did not change

my standpoint an iota. Everyone else did. Go read all my previous posts if you don't believe me. Everytime I said

something that you guys said was impossible, or absurd, or irrational was because it followed as a consequence

of statements that either you, or Rishi, or Daniel, or Reichmann made. (I kept saying reductio ad absurdum

for this very reason - to prove that the opposite of the absurdity has to be true.) This whole huge thread

is in front of you - go see if I made one absurd statement that did not

follow as a consequence of the "binary camp's" hypotheses.

At this point it I who should welcome you to my world - the actual real one.

rishij · November 16, 2008

Vijay:"My point was that even if an individual particle is invisible to the naked eye, it contributes to tone.

Its contribution maybe say 0.0000001% so if you take a billion of them you get tone."

Duh, that's how reduced silver metallic atoms form a B&W photographic image... :)

Rishi

bernardwest · November 16, 2008

Daniel categorically stated that particles below a certain size, no matter how many of them you take together, could never contribute to the formation of tone that we could perceive.

Um, I don't remember that. Point me to the post where he says that please.

My point was that even if an individual particle is invisible to the naked eye, it contributes to tone. Its contribution maybe say 0.0000001% so if you take a billion of them you get tone.

So how big is a billion of them? See where we are coming from Vijay? You can't claim that tonal resolution is down at the granular level if it takes billions (or even millions, or even thousands, or even more than 1) before tone is percetible. Argument over? Good.

Similarly Daniel's point was that a silver speck, no matter how small would always be opaque, i.e., absorb 100% of the light that fell on it (and passed 0%). The whole diamond/thin film/sputter coat thing was to disprove this - my point being that for a small enough silver speck, light would pass through the silver itself. Of course when light passes through something, that thing is not opaque.

I agree with you. Once again, though, this is largely irrelevant to the debate about film vs. digital resolution.

You seem to imply that I changed my point of view (hence the welcome), yet the reality is that I did not change my standpoint an iota. Everyone else did. Go read all my previous posts if you don't believe me.

You spent the first half or so of this thread trying to repeatedly argue that the concept of a binary switch was absurd in the production of silver deposits. I proved you wrong on this, and thankfully, you ceased that line of reasoning. You also spent a large amount of time trying to argue that grains would need to be sentient(!?!) to form the kinds of formations seen in Daniel's 400x images. Regardless, this is all part of a good discussion, we (even you Vijay) learn new things along the way. Just please stop acting like you have had a coherent argument all along. Virtually none of us have.

rishij · November 16, 2008

"Daniel's point was that its contribution was 0% - which means you could take quadrillions of them and still couldn't form tone. After all 0 multiplied by any number is also 0.

Similarly Daniel's point was that a silver speck, no matter how small would always be opaque, i.e., absorb 100% of the light that fell on it (and passed 0%). The whole diamond/thin film/sputter coat thing was to disprove this - my point being that for a small enough silver speck, light would pass through the silver itself. Of course when light passes through something, that thing is not opaque.

Daniel said that light couldn't pass through a gap that was smaller than the wavelength of that light - and by invoking diamonds, I pointed out that interatomic gap between..."

Vijay, I don't think Daniel argued any of these things. I think that your rigorous & absolute interpretation of Daniel's words led you to believe he was saying these things. And so that's why I've been saying all along I think you're arguing to yourself.

I myself said that yes filamentous growths can perhaps represent a small number of tones from a distance, but the overwhelming contributing factor is its size, 'opaqueness' (at least compared to the film base around it), and the density of such clusters. I think this is exactly what Daniel is arguing when he says that, at reasonable magnifications, they really only look black, so their 'blackness' and their size is the largest contributing factor... not the 10 or so tones that might be generated at some given magnification for some particular sized filamentous growth.

"This was the entire thrust of Reichmann's argument - that silver specks are either clear or opaque (binary) but digital pixels are analog."

For all practical purposes, he's right. Take any given size of silver speck that you're looking at... Let's say a silver speck that is 400nm in diameter (arbitrary). How many tones do you actually think that can represent? A larger area, using the halftone process, on the other hand, can represent many more tones. Digital pixels are 6 micron photon counters... so for a 6 micron are, are far more 'analog' than film in that it can represent more tones for that given area. Hence its higher 35mm equivalent resolution. Is film still analog? Of course... different sized silver specks and different densities within a given area.

"Again, if the particle is either clear or opaque, a different set of resolution numbers result (artificially low); whereas if the particle could be in between, a different set of resolution numbers result."

Artificially low? Maybe a bit off, yes, because he's not rigorously considering the variety in sizes of silver filamentous growths, and that a region the size of 1 grain can have many filamentous growths, of many sizes. Which can up the resolution BUT STILL KEEP IN MIND it's a halftone process. Because each tiny filamentous growth itself mostly likely cannot possibly represent that many tones (because of the chemistry of reduction from a single sensitivity center). In high numbers, of course it can represent many tones.

You say 'if the particle could be in between, a different set of resolution numbers result'... where? Where's your calculation? I gave you a believable and reasonable calculation based on a halftone process. Where's yours? And why are you still talking about 'the particle'? Which particle? The grain that's no longer there after development? Or the filamentous growth from a sensitivity center?

Branch out Vijay, and stop repeating lines you've said many times before. Why have you not given me a resolution calculation? Why have you not addressed my line of reasoning that filamentous growths, each one by itself, is most likely to be dense without large gaps because of the process of electron transport and reduction of successive (adjacent) AgBr ions? Stop sticking to your guns, and putting all your eggs in one basket, and try on a new theory for size. I did, and it's brought me here, to some middle ground that *explains the observations*. Your theory doesn't explain:

<ul>

<li>The megapixel, not gigapixel, resolution of 35mm film</li>

<li>Why we see mostly black specks on the microscope</li>

</ul>

You just ignore these, and keep repeating yourself, and at this point it's unacceptable. With all due respect, do something about it or quit posting posts where all you do is repeat yourself ad nauseam.

Rishi

rishij · November 16, 2008

Bernie:"Just please stop acting like you have had a coherent argument all along. Virtually none of us have."

Thank you!! I couldn't have said it better. I'd also like to add 'some of us are man enough to admit when we're wrong'... something Vijay is not intent on doing. Shows a lack of humility, I must say.

Remember, Vijay, when you went around touting that tone and resolution are absolutely independent in this discussion??

For the good of this thread, you should probably admit you were wrong there, so other readers don't get mislead. Though I already showed exactly why they *are* interdependent... someone may miss it.

danielleetaylor · November 16, 2008

Vijay,

Responding to multiple comments from multiple posts...so this is long.

Statement x: they're too small to be observed under an optical microscope

Does not necessarily imply

Statement y: they're too small to make any difference in the perception of detail or tone in a final print at

much lower magnifications

It absolutely does. If you can't see it at 400x, you certainly are not going to see it at 10x.

But tone can be created even if the particles are too small to observe - for instance with pigments. The

individual "particles" of the pigment are far too small to be observable under an optical microscope, but they

form tone just fine.

No tone is created by placing one pigment on a material. Billions upon billions upon billions of

pigment particles are placed on a material before enough light is affected to create any tone to our eyes.

(Actually it's probably some order of magnitude well beyond billions, but you get the point.) You do not perceive

any individual pigment, you perceive a thick coating of them.

Beyond that, if you observe pigments at 400x they are still colored. It's obvious that their inherent tone, as

a solid material, forms the basis of tone observed at lower magnifications when in sufficient concentration to

be observed by the human eye.

We haven't observed one "gray grain", at any magnification, much less do we see them in sufficient number to

be the basis of tone in B&W film. Even if your, at this point entirely theoretical, gray grain exists, it

certainly does not appear with enough frequency to affect tone. Put another way, if I have a frame with mid gray,

and I place that frame under a microscope, and I don't see any mid gray grains but instead clumps of opaque

grains, then I have to conclude from the evidence that the mid gray tone at normal print sizes is rendered by the

dithering of opaque clumps of grains. For the mid gray to be formed by "gray grains" I would have to see them,

many of them, almost all of them would have to be mid gray. I've never seen one.

When making these arguments you tacitly assume that silver particles are opaque.

Again I ask if you've ever observed a translucent grain. If observations show nothing but opaque grains, then

grains are opaque. We see light, therefore we can tell if something is opaque or not simply by observing it. If

we observe it is opaque, then it is opaque. No amount of hypothetical double talk can change

this. To suggest to me that the grains I observe to be opaque to my eyes are in fact not opaque to my eyes is to

question the very foundation of the scientific method. You might as well paraphrase the Matrix and tell me "There

is no grain" because that's how far away from the scientific method you are. You are literally questioning the

assumptions of reality upon which the scientific method is based.

But the answer is key to proving your argument.

Observation has proven the argument beyond doubt to anyone who will observe. Adams/Reichmann's description

conforms to evidence and predicts what we observe, that digital cameras do not need gigapixels to match film,

only megapixels. If sub-micron silver grains behaved like pixels, 35mm film would contain the equivalent of

gigapixels of usable image data (and Petrana's 4x5 camera would be worthless).

You gloss over this point as if it is too insignificant to care about, yet this could be giving you "gray"

specks of silver and you not knowing it.

If I do not "know" it, i.e. I do not observe it, then it might as well not exist. The whole point of taking a

photograph is to observe it. If I cannot observe and "know" a gray grain exists, then it cannot possibly form the

basis of gray tones.

I know that the inherent tone of a pigment is the basis of tone at a macro scale because microscope

observations reveal that tone. No such tone is found in silver grains.

This is like saying that you can't see pigment "particles" under a microscope so pigments can't possibly

form tone on paper.

Your problem is one of quantity. If gray grains formed the basis of gray tones, they would be observed in

great quantity. They would have to exist in great quantity to form tone at a macro scale. At this point we

haven't seen even one.

"Under an optical microscope we see opaque specks of silver. We don't know whether these are all that

affect tone or there are other phenomena that may affect tone that are not observable with an optical

microscope."

If I can't see a gray grain at 400x, then there's no chance said gray grain could be affecting my perception

at 10x. Even a pigment, which does have inherent tone that can be observed under a microscope, if deposited in

such a small amount that it can only be observed at 400x, will have effectively no impact on observation at 10x.

Let me ask you this Vijay: do you have to clone out dust spots on your images due to nanometer scale particles

of matter too small to be seen under a microscope? No. Is your enjoyment of prints ruined because of said

particles which no doubt both collect on the surface and sit between you and the print, hanging in the air? Nope.

Why?

They're too small to impact your perception of the image. Let's go to a larger scale. We know the air is filled

with bacteria and viruses. That's why we get sick. Do you have to clone out bacteria spots? Do they obscure your

view of a print? Does the color or tone of a print change if someone is sick and sneezes bacteria into the air

between you and the print? In theory if a colony of bacteria formed with sufficient height, width, and depth such

that the entire colony could be seen by the human eye, then you could say that colony impacted your view. Do

we see any colonies of gray grains under microscopes? Nope.

As of this point there is no evidence and no reason what

so ever to believe that gray or translucent grains ever occur or exist. Silver is inherently opaque. That's the

fundamental nature of its interaction with light. It is on you to prove translucent silver grains exist

through observation. If they occur at sufficient frequency to form tone in prints, then they are by definition

observable. So where are they?

Also you can make light gray + light gray = dark gray, but not black + black = any shade of gray. If the

silver specks are opaque, a clear section of film has no silver specks, and an opaque area of film could have any

number, stacked on top of each other even, but always resulting in full opacity.

At low magnifications your eye cannot perceive the individual opaque specks and clear areas. They are blurred

to gray. So yes, you can make black + black = any shade of gray by varying black with clear (or white in the case

of printing on paper) over a region if the alternating areas of black/clear are below the resolving power of

the observer, but the total region of alternating black/clear is within the resolving power of the observer.

I experimentally prove this every single time I print a B&W photo using my R800 and QuadToneRip, which uses

only the matte black ink yet can generate an amazing array of gray tones.

Oh and Rishi, don't forget to do a similar analysis for chromogenic (C41) B&W. This is presumably made of

dye clouds a bit larger than grains in conventional silver halide film. Say 5 microns x 5 microns at most for a

dye cloud.

Silver halide grains are typically below 1 micron, with the largest

size being around 2. Dye clouds start at 3 and range to 10.

But there is an important difference - a single dye cloud can represent all 64K tones or maybe even more,

so is effectively a complete pixel.

Doubtful. It might be able to represent 3 or 4 tones. There's not a precise way to calculate a number, but

under a microscope individual dye clouds certainly do not appear in 64,000 different shades. BUT since they are

translucent and occur in 3D space, they can stack to generate more tones within an area approximately the size of

one dye cloud. Whether or not they can hit 64K within 5 microns I could not tell you. It would require

experimentation involving precise deposits of dye clouds, which I am not able to perform.

Oh and if only particulate matter that is visible at "human perceivable magnifications" could contribute to

tone, then pigments wouldn't work at all.

A single pigment particle on a material would not work at all. For pigments to work the material must be

coated with them so that, as a group, they interfere with light at a size which can be observed by the human eye.

This one from Rishi: No, proving film grain is binary (which we haven't really done and none of us even

intends to do at this point) would make film vastly inferior to equivalent sized digital sensors. Luckily, it's

more complicated than

that.

Silver is only opaque, only one tone. The combination of silver and clear base is binary in tone (not

dimension). That doesn't make film vastly inferior because film works with sub-micron grains while digital has

much larger pixels.

If silver could assume any tone as Vijay proposes than it would be digital which was at a serious disadvantage

because it would be up against a medium with sub-micron "pixels."

Damn, man, it sounds like you don't understand the meaning of the word opaque. You can't stack opaque

grains on top of each other and expect density to increase. A coin is opaque. Stacking ten coins on top of each

other results in a structure that is also opaque.

You can if they're not perfectly aligned. 10 coins at random overlapping positions will present a larger

opaque area than one coin. 10 coins arranged in 2D space with clear spaces between them and a light shining

behind them will appear as a gray spot to an observer too far away to be able to visually resolve the individual

coins and spaces, but within a distance where the entire group can be resolved as a group.

a. Assuming what Daniel says is true.

b. Deriving conclusions based on this.

c. Showing that the conclusions are absurd. Proof - your annoyance at me.

Vijay, with all due respect, you're not refuting anything. Your conclusions always involve assumptions on your

part that either were never stated, or that are demonstrably false. You build complex hypotheticals that contain

fatal flaws and bear little analogy to the real world process going on.

Those black specks when looked at closely (50,000 times mag) are filamentary like a wire wool pad, the

density of that pad is dependent on how many photons strike the grain, and the grains are stacked so density

varies normally between 0.10 - 3 density. Mark

This statement is false. The "wire pads" have to be imaged using electrons precisely because the gaps are too

small to pass light waves. Even Kodak states that the wire pads appears as single particles under optical

conditions.

One other comment: you are not safe from microwaves exiting the screen holes because the microwave is a

Faraday cage. It is a Faraday cage, and that is why such a thin metal screen is opaque to the microwaves. But the

reason the microwaves do not escape the holes in that opaque material is because they are smaller than the

microwave wavelength. You could experimentally verify this by ripping a hole in the screen larger than the

wavelength, but I do not recommend that. Standing in front of a microwave with a large enough rip in the screen

will cause you to suffer burns. And your eyes would be one of the first areas to burn. So don't try that

experiment at home kids.

rishij · November 16, 2008

"This one from Rishi: No, proving film grain is binary (which we haven't really done and none of us even intends to do at this point) would make film vastly inferior to equivalent sized digital sensors. Luckily, it's more complicated than that.

Silver is only opaque, only one tone. The combination of silver and clear base is binary in tone (not dimension). That doesn't make film vastly inferior because film works with sub-micron grains while digital has much larger pixels.

If silver could assume any tone as Vijay proposes than it would be digital which was at a serious disadvantage because it would be up against a medium with sub-micron "pixels."This one from Rishi: No, proving film grain is binary (which we haven't really done and none of us even intends to do at this point) would make film vastly inferior to equivalent sized digital sensors. Luckily, it's more complicated than that.

Silver is only opaque, only one tone. The combination of silver and clear base is binary in tone (not dimension). That doesn't make film vastly inferior because film works with sub-micron grains while digital has much larger pixels.

If silver could assume any tone as Vijay proposes than it would be digital which was at a serious disadvantage because it would be up against a medium with sub-micron "pixels."

Agree with everything you say there, Daniel. What I was trying to say was: if each silver halide crystal could only go to black or nothing, then we'd have a problem. I think you and I both agree that, since the actual crystal is dissolved away during development, it's the filamentous growths from sensitivity points arranged around the surface of the crystal that matter, and these *can* be subgranular in size. So, yeah, binary down to the silver atoms, but analog in the sense that the filamentous growth sizes can vary, and can be subgranular in size. Thereby making film not as pathetic as it would be if a whole silver crystal could only be clear or black. Which is not the case.

"Vijay, with all due respect, you're not refuting anything. Your conclusions always involve assumptions on your part that either were never stated, or that are demonstrably false. You build complex hypotheticals that contain fatal flaws and bear little analogy to the real world process going on.Vijay, with all due respect, you're not refuting anything. Your conclusions always involve assumptions on your part that either were never stated, or that are demonstrably false. You build complex hypotheticals that contain fatal flaws and bear little analogy to the real world process going on."

Couldn't have said it better. I really feel like Vijay's not doing any thinking here, not trying to build or add to the model, but only playing Devil's advocate. What really ticks me off is that he doesn't answer to some of my burning flaws I point out in his argument. That you & Bernie also point out.

As for the microwave analogy... some light does make it thru gaps smaller than the wavelength of the light, correct? Otherwise the double slit experiment would never have worked? Correct me if I'm wrong.

Rishi

danielleetaylor · November 16, 2008

Vijay,

Daniel categorically stated that particles below a certain size, no matter how many of them you take

together, could never contribute to the formation of tone that we could perceive.

I never said that.

I was merely disproving that with the pigment particle explanation. In a pigment, particles are below that

certain size that Daniel postulated, yet they form tone.

They form tone only when they occur in groups large enough to be perceived by the human eye.

Daniel's point was that its contribution was 0%

Nope. My point is that your hypothetical gray grain does not exist. If it did exist at sufficient frequency

to contribute to the perception of gray tone in B&W film we would, by definition, be able to observe it. You

cannot have something that is both observable and not observable. And that is the reductio ad absurdum

which disproves your claim of grains influencing perception of tone at 10x yet not being observable as gray

(anything other than opaque) at 400x.

Similarly Daniel's point was that a silver speck, no matter how small would always be opaque, i.e., absorb

100% of the light that fell on it (and passed 0%).

Also never said. At very small nanometer scales solid matter is not opaque. But silver halide crystals do not

occur at those scales.

my point being that for a small enough silver speck, light would pass through the silver itself. Of course

when light passes through something, that thing is not opaque.

I do not claim that it's impossible for some hypothetical, ultra thin coating/arrangement of silver atoms to

appear as translucent. With nano technology or the coating techniques we use to coat lenses we may be able to

create arrangements which do not occur naturally

and have transparent or translucent properties. I do claim that such a hypothetical arrangement is never observed

in B&W film

because naturally arranged solid silver is not translucent. B&W film is

simply not structured in some hypothetical translucent way. The silver growths created by developer are not

structured that way.

Daniel said that light couldn't pass through a gap that was smaller than the wavelength of that light - and

by invoking diamonds, I pointed out that interatomic gap between the carbon atoms that make up diamond is many

orders of magnitude smaller than the gap

You are confusing the atomic/molecular properties of a material which determine whether or not it is

transparent to light with what happens when you try to pass light through a hole in an opaque material

which is smaller than the wavelength of light. Silver is by nature opaque. So if you have a gap in a deposit of

silver atoms smaller than the wavelength of light, light will not pass.

You can prove this again with your microwave. Microwaves penetrate the coffee, meat, lasagna, etc that you

place in your microwave, and their interatomic gaps are no where near the scale of the holes in the door screen.

Yet the holes in the door screen protect you while letting you observe your food. The reason is because the foods

you cook are transparent to microwaves (er...translucent) while the metal screen is opaque to the same radiation.

Again, if the particle is either clear or opaque, a different set of resolution numbers result

(artificially low); whereas if the particle could be in between, a different set of resolution numbers

result.

I hate to tell you this, but if you assume grains can be gray in tone then resolution calculations for film

end up much, much higher than we observe them to be in real life. Reichmann set out to explain this apparent

contradiction by pointing out that grains are not pixels and cannot assume any tone. It is his theory

which yields correct and verified predictions.

go see if I made one absurd statement that did not follow as a consequence of the "binary camp's"

hypotheses.

All of them. You added twists and turns and unstated assumptions in every single case.

bernardwest · November 16, 2008

As for the microwave analogy... some light does make it thru gaps smaller than the wavelength of the light, correct? Otherwise the double slit experiment would never have worked? Correct me if I'm wrong.

I agree with this Rishi. Nevertheless, I believe it is fairly irrelevant to the crux of our discussion (which, for the sake of Vijay, is tonal resolution). You temp fate my friend in agreeing in any small part with Vijay, as then he will claim that he has been right all along ;)

By the way, when do you people sleep? It is 7pm here in eastern Australia, so it's not quite my bedtime yet.

rishij · November 16, 2008

Daniel:"Microwaves penetrate the coffee, meat, lasagna, etc that you place in your microwave, and their interatomic gaps are no where near the scale of the holes in the door screen."

Whoa whoa whoa. You're not tryina say that the interatomic spacing in the food is larger than the inter-hole spacing in the holes on the door screen, are you?

rishij · November 16, 2008

Bernie, I try to sleep as little as possible as I find it a huge waste of life. Unfortunately, though, it's necessary. And I wonder every day why Evolution hasn't taken care of that yet. Oh wait, probably because Evolution only cares for survival & procreation, not productivity. Damn you, Evolution!

Rishi

vijay_nebhrajani · November 16, 2008

Rishi: "But, I have to argue & ask you this: In Reichmann's article, he says that a grain has to be binary?

What's a 'grain' in developed film anyway? What's your definition of a 'grain' in developed film, where there are

no more 'silver halide crystals' because the non-reduced silver halide salts are dissolved away... "

There is a standard definition of film grain. It is the silver halide crystal itself. Hence you notice

that I've been using the word "silver speck" to mean what is left behind on processed film i.e., to disambiguate

the word "grain". A silver speck is a self contained entity - i.e., a quantity of metallic silver surrounded by

gelatin or empty space on all sides, regardless of its size.

There were some initial arguments about this - that a grain (i.e., a crystal) was binary, to which I pointed out

that if it were so, a billion molecules of silver halide would have to suddenly change state to silver, because

that kind of binary implied switching - like mousetraps. Hope you remember those discussions. (Binary = only two

states, no intermediate ones. So either all silver halide, or all silver - the whole billion atom thing at once).

Evidently this is absurd, so that argument (both you and Daniel made it, don't make me quote you) was

dropped. You guys then went to the "silver speck" is binary argument - meaning that silver, if present is either

clear or opaque.

I then pointed out that the silver halide converts to silver over time, as development proceeds, so the silver

speck "grows". After development is

stopped, if the resultant silver speck is thin enough, it would pass light through, like the sputter coated gold

film. Hence, even the silver speck (the thing seen with a microscope) couldn't be binary (clear, meaning absent,

or present, meaning opaque). It could be present, but say 50% transmissive.

Rishi: "I still would argue that once a reduction reaction is initiated at a 'latent' or 'exposed' sensitivity

center, the resultant clump is most probably not gonna have many huge gaps in it"

My argument is not about gaps - it is that if the silver speck left behind after processing is thin

enough the

silver itself will pass light. Nothing to do with the gaps. The photons will sail through the metallic silver

atoms, as they do through thin films of gold etc. Those gold films don't have holes at all, the light goes

through the metal.

Now as the silver grows from a few atoms thick - it is transparent in the beginning - and as its size increases

with development, it becomes less and less transmissive. Depending on its size when development stops, it could

have any transmissivity value from 100% to 0% - all possible tones.

Rishi: "I think that, macroscopically, it's the halftone process that makes tones."

We are trying to figure out whether it is a halftone process or not. You are jumping to the conclusion, or

putting the cart before the horse - or engaging in a recursive argument - it is a halftone process so silver

specks must be opaque; and then saying that because those silver specks are opaque it is a halftone process.

Rishi: "Again, if thousands of tones could be represented by an area of film the size of one initial silver

halide crystal (what I'm calling a 'grain'), then the realistic resolution of 35mm film would be in the gigapixel

range."

No, now you are confusing tone and resolution again. Our previous resolution calculations (that resulted in 10

cpmm or 1 cpmm etc) were obviously wrong - they were part of the reductio ad absurdum proof. Here is the

correct calculation.

There is an upper limit to resolution in film - it is the size of the largest silver halide crystal in the

film, even if smaller crystals are also present. Nothing to do with silver specks at all, nothing to do whether those

silver specks have tone or not.

This is because the process of formation of metallic silver when photons enter a silver halide crystal is not

immediate. It is contingent upon the development, which happens at a later time - like a day later or a month

later, or ten minutes later.

What happens is that the information about the light pattern falling on that single crystal is lost (so if

10 line pairs fell on a single silver halide crystal, we still couldn't guarantee that as the metallic silver

forms, it will form in that pattern of light and dark lines). That information is long gone, being replaced

instead with a number of silver ions, free to roam inside the crystal and migrate to sensitivity centers (it is

actually electrons which move around). These moving electrons trace out random paths, eventually creating a

random filamentary structure of silver that terminates on a sensitivity center (as you trace back from the tip of

a filament).

Thus, a crystal (not a speck) is the limiting factor for resolution. But when a crystal is eventually

dissolved

away, it leaves behind silver in proportion to the sum total of light that fell on the crystal (an integral

function actually), so it works as a photon counter - the amount of silver is proportional to exposure -

that is what a "photon counter" really is. You're not really counting the photons going "1 million three hundred

twenty three thousand seven hundred and sixty nine" ...

Again, larger crystals degrade resolution more than smaller crystals (more information is lost by a larger

crystal than a smaller one), so when there are larger crystals present, it doesn't matter if there are smaller

crystals present - the larger crystals spoil it for everybody. Hence resolution bounded by the size of the

largest silver crystal.

Having this insight, that the final silver speck size has nothing to do with resolution, you'll ask: what's the

max silver halide crystal size for film? Daniel said 0.2 - 2 microns. But since those are probably mean or median

numbers,

I'll take 5 microns as the worst case largest crystal size for the best, sharpest, slowest film.

Then my max resolution (theoretical upper bound) calculation is simple - 5 microns x 2 for a line pair - i.e, a

line pair = 10 microns, i.e, 100 cpmm, i.e., a max of 35 MP for 24mm x 36mm (full frame) 35mm film. Thats it. No

more possible. We already said best, sharpest, slowest film, so other films would fare worse.

This calculation is so in line with Mauro Franic's experiments, its scary. His experiments suggest an average of

35.1 MP for 35mm film.

Now, regardless of just how many or how few tones can be formed by a single crystal of silver halide you'll find

that the upper limit for resolution has nothing to do with these tones. It is limited by the size of the largest

crystals. Smaller crystals would contribute in the formation of silver specks as would the larger ones. They may

even improve the tonality by "filling in" the clear areas, as could partially transmissive silver specks. But it

is the largest crystals that impose a resolution bound, independent of tonality.

Now do you get the independence of tones from resolution limit thing I was saying like 80 posts ago? That you

shouldn't confuse tonality and resolution?

OK, I'll admit that this is the first time I've actually explained the my resolution calculation (the correct

one) in detail, so you are forgiven for confusing tonality with the upper resolution bound.

danielleetaylor · November 16, 2008

Rishi,

I think we're on the same page regarding what happens at the subgranular level.

As for the microwave analogy... some light does make it thru gaps smaller than the wavelength of the light, correct? Otherwise the double slit experiment would never have worked? Correct me if I'm wrong.

Am I missing something? That experiment does not require slits more narrow than the wavelength of light. You can find instructions for doing it online. They don't say anything about slits in the nm range (which would presumably be impossible for the average person to create), they just say "narrow slits". It was first done in 1801, and I would guess nm sized slits would have been impossible to form using 1801 technology.

Practically, you cannot image something smaller than the wavelength of the radiation you're using to try and image it. If you want to get into the nitty gritty details, there can be evanescent waves and "leakage" related to just how small the holes are relative to the wavelength. And some specific materials under specific conditions permit the transmission of radiation through holes smaller than the radiation wavelength.

But for all practical intents and purposes, if there is a gap in silver on film that is smaller than the visible wavelengths, it's going to effectively block light and prevent observation of the gap.

danielleetaylor · November 16, 2008

Rishi,

I think we're on the same page regarding what happens at the subgranular level.

As for the microwave analogy... some light does make it thru gaps smaller than the wavelength of the light,

correct? Otherwise the double slit experiment would never have worked? Correct me if I'm wrong.

Am I missing something? That experiment does not require slits more narrow than the wavelength of light. You

can find instructions for doing it online. They don't say anything about slits in the nm range (which would

presumably be impossible for the average person to create), they just say "narrow slits". It was first done in

1801, and I would guess nm sized slits would have been impossible to form using 1801 technology. I have to admit

I have not done it personally, but I'm not aware of any requirement for nm slits.

Practically, you cannot image something smaller than the wavelength of the radiation you're using to try and

image it. If you want to get into the nitty gritty details, there can be evanescent waves and "leakage" related

to just how small the holes are relative to the wavelength. And some specific materials under specific conditions

permit the transmission of radiation through holes smaller than the radiation wavelength.

But for all practical intents and purposes, if there is a gap in silver on film that is smaller than the

visible wavelengths, it's going to effectively block light and prevent observation of the gap. If you can't

observe the gap, then it certainly is not affecting your perception of tone in a final print.

Whoa whoa whoa. You're not tryina say that the interatomic spacing in the food is larger than the

inter-hole spacing in the holes on the door screen, are you?

Quite the opposite. I was trying to point out to Vijay that he was confusing interatomic gaps in transparent

materials with sub-wavelength gaps in opaque materials. Therefore his diamond example does not mean that

radiation can just pass through an opaque material with holes smaller than said radiation's wavelength.

Thank God...if Vijay was right we would all have burns from our microwave ovens ;-)

rishij · November 16, 2008

Vijay:"You are jumping to the conclusion, or putting the cart before the horse - or engaging in a recursive argument - it is a halftone process so silver specks must be opaque; and then saying that because those silver specks are opaque it is a halftone process."

Are you crazy? The silver specks are opaque, for all practical purposes, TO BEGIN WITH, because that's how they look under a microscope...

WTF?!?!

Rishi

danielleetaylor · November 16, 2008

There were some initial arguments about this - that a grain (i.e., a crystal) was binary, to which I

pointed out that if it were so, a billion molecules of silver halide would have to suddenly change state to

silver, because that kind of binary implied switching - like mousetraps. Hope you remember those discussions.

(Binary = only two states, no intermediate ones. So either all silver halide, or all silver - the whole billion

atom thing at once).

Evidently this is absurd, so that argument (both you and Daniel made it, don't make me quote you) was

dropped.

No, the argument was clarified. Big difference. Grains are binary in tone, not size. (More precisely, a

region of film which can have silver or be free of silver is binary in tone. Silver is not binary in tone, it is

one tone.)

After development is stopped, if the resultant silver speck is thin enough, it would pass light through,

like the sputter coated gold film.

But we don't ever observe 50% gray silver specks, do we? :-)

My argument is not about gaps - it is that if the silver speck left behind after processing is thin enough

the silver itself will pass light. Nothing to do with the gaps. The photons will sail through the metallic silver

atoms, as they do through thin films of gold etc. Those gold films don't have holes at all, the light goes

through the metal.

Your argument assumes that something will occur naturally which in practice requires very precise, technical,

and directed efforts on the part of humans to achieve. Hypothetically your "gray grain" may be possible. I

wouldn't know how to place the odds on its formation. I can guess the odds would be excessively high, which is

confirmed by the fact that they are not observed.

We are trying to figure out whether it is a halftone process or not.

You keep missing the point that it is observed to be a halftone process. You keep trying to build

reductio ad absurdum arguments to disprove this. I don't know why I didn't think of it this way before, but your

theory that grains could be observed as gray at a lower magnification yet appear opaque at higher magnification

is reductio ad absurdum. You cannot have something that is both observable and not observable (weirdness at the

quantum level not withstanding...we are dealing at the level of classical physics). A grain cannot be gray at 10x

then disappear, or change to black, at 400x.

Re: resolution calculations

Adams'/Reichmann's description correctly predicts that film should have higher resolution with monochromatic

targets than grayscale targets. It does. Your theory suggests the resolution should be the same. It's not.

Adams'/Reichmann's description correctly predicts that film will be observed to have higher resolution than a

digital sensor with pixels larger than grains with a monochromatic target, yet in practice will show equal or

less resolution with

grayscale targets. This is what we observe. Your theory predicts that film would always maintain a very

significant resolution advantage over digital sensors. It does not.

But when a crystal is eventually dissolved away, it leaves behind silver in proportion to the sum total of

light that fell on the crystal (an integral function actually), so it works as a photon counter - the amount of

silver is proportional to exposure - that is what a "photon counter" really is.

Exposure/development result in more complete conversion to silver, not a change in tone. Silver is silver. It

is opaque.

Having this insight, that the final silver speck size has nothing to do with resolution, you'll ask: what's

the max silver halide crystal size for film? Daniel said 0.2 - 2 microns. But since those are probably mean or

median numbers, I'll take 5 microns as the worst case largest crystal size for the best, sharpest, slowest

film.

The source I got that from labeled it as a range, not a median. I don't think fine grained B&W film has 5

micron cystals. (Or it they occur, they are exceedingly rare.)

Then my max resolution (theoretical upper bound) calculation is simple - 5 microns x 2 for a line pair -

i.e, a line pair = 10 microns, i.e, 100 cpmm, i.e., a max of 35 MP for 24mm x 36mm (full frame) 35mm film. Thats

it. No more possible. We already said best, sharpest, slowest film, so other films would fare worse.

This calculation is so in line with Mauro Franic's experiments, its scary. His experiments suggest an average

of 35.1 MP for 35mm film.

Where was it determined that 35mm film was = 35 MP? Films are observed to yield 50-80 lpmm at 1.6:1 contrast on a

monochromatic target. That works out to 10-26 MP on a monochromatic target. The reason people say their full

frame 12-24 MP cameras "out perform" 35mm film is because the film's resolution drops substantially when dealing

with tone. That should not occur under your theory.

danielleetaylor · November 16, 2008

Rishi,

Are you crazy? The silver specks are opaque, for all practical purposes, TO BEGIN WITH, because that's how they look under a microscope...

WTF?!?!

You just put into words my thoughts regarding this entire discussion with Vijay ;-)

danielleetaylor · November 16, 2008

Petrana, I'm still baffled by the whole concept of this argument. What are you people trying to prove? that digital is better? that film is better?

Nothing so general. I'm trying to prove that grains are opaque and Vijay is trying to prove they are translucent.

Do you realize that throughout the lifetime of this thread alone, you could've either filled half a terabyte of digital captures, or shot an entire portfolio on 4x5 (and have it processed and scanned?).

I don't think I could have shot THAT much.

Normally I might agree with you Petrana, but as I've said I'm in no condition to go shooting due to a sinus infection. This long winded conversation is just a mental exercise. It's entertaining in the same way chess can be entertaining. This makes us think a little bit and do some research, so it's an interesting diversion.

I don't think I would have ever put this much time into it if I were well. But I certainly don't feel as guilty about it as, say, I would if I watched American Idol ;-)

rishij · November 16, 2008

Vijay: "Now, regardless of just how many or how few tones can be formed by a single crystal of silver halide

you'll find that the upper limit for resolution has nothing to do with these tones."

No, no, no, no, no, no, no. I disagree 100%. Resolving black & white is very different from resolving tones.

Precisely BECAUSE it's a half-tone process. Which explains exactly why a 35MP digital image has SO MUCH

MORE real-world resolution than any Imacon or drum scan of 35mm film!!! Vijay, have you ever even tried to

scan 35mm film? I'm guess no, otherwise you'd never find yourself making such ridiculous claims.

Vijay"What happens is that the information about the light pattern falling on that single crystal is lost...

That information is long gone, being replaced instead with a number of silver ions, free to roam inside the

crystal and migrate to sensitivity centers (it is actually electrons which move around)."

Nope, remember they say it's something like 3-50 silver ions have to be reduced per sensitivity center to render

the entire grain 'developable'. But, you know what, since we're doubting the entire literature anyway, scratch

that. Spectral sensitizers have to pass electrons onto silver ions (or sensitivity center electron traps). How

many of these can you have per crystal? Certainly many many orders of magnitude below the number of AgBr ion

pairs per crystal. So, 'that information about the light pattern falling on that single crystal' cannot convey

more tones than the number of spectral sensitizer molecules per crystal... so can somebody please figure out how

many such spectral sensitizer molecules can exist per crystal?

Also please figure out if spectral sensitizers can recycle electrons, in which case my entire argument falls apart...

Rishi

vijay_nebhrajani · November 16, 2008

Daniel: Adams'/Reichmann's description correctly predicts that film should have higher resolution with

monochromatic targets than grayscale targets. It does. Your theory suggests the resolution should be the same.

It's not.

What's so hard to understand about a "theoretical upper bound"? It means you can't get better - you certainly can

get worse.

Also, do you mean to say that with digital, resolution at grayscale targets is the same as for monochromatic

targets then? It isn't. Going

from a monochromatic target to a grayscale target is merely decreasing the amplitude of the signal; thereby

increasing the signal to noise ratio and making the signal harder to detect. Regardless of film or digital;

resolution will drop as contrast drops. This

is true even for lenses, let alone recording media like film or digital. You can't use this to prove anything,

sorry.

The source I got that from labeled it as a range, not a median. I don't think fine grained B&W film has 5

micron cystals. (Or it they occur, they are exceedingly rare.)

Rich Evans posted an SEM micrograph of a single crystal of TMax 400 that is at least 10 microns in the dimension

seen. Here's another: <a

href="http://www.kodak.com/US/en/corp/researchDevelopment/whatWeDo/technology/chemistry/silver.shtml">from

Kodak</a> - also 10 microns, although they don't say which film.

5 microns seems quite possible, even likely as the largest grain size.

Films are observed to yield 50-80 lpmm at 1.6:1 contrast on a monochromatic target. That works out to 10-26 MP

on a monochromatic target.

At contrast 1.6:1, you are already talking grayscale target - the usual contrast ratio is 1000:1 (black on white)

- but 1.6:1 means that the darker of the two lines (both gray) - is darker than the other by a factor of just 1.6.

This is a target that has "tone", something quite easily observable too. Hopefully you're not going to argue

"number of different tones" now. See attached image for what happens at 2% contrast (a ratio of 1000:1 x 2/100 =

20:1).

Credit to http://www.normankoren.com/Tutorials/MTF.html - fair use and all that. You have two grays (tones)

barely distinguishable from one another.

Per Reichmann/Adams' theory this should result in extremely low resolution, not the 50-80 cpmm commonly seen and

also quoted by you.

Also, based on the fact that dye clouds in color film can and do form continuous tones this is NOT a halftone

process - so color film should outresolve B&W silver halide film by a wide margin, right? It doesn't at all, for

the same given speed - the color film has worse resolution numbers than silver halide film of the same speed.

I said: "This calculation is so in line with Mauro Franic's experiments, its scary. His experiments suggest an

average of 35.1 MP for 35mm film."

That was a little tongue in cheek - look at my earlier post on this subject. It just happens that two numbers are

surprisingly

close, and I made an attempt at humor about that. Ignore it.

vijay_nebhrajani · November 16, 2008

Retrying image attachment

nigel meaby · November 16, 2008

"and also in attracting the best mate by setting ourselves apart from other males and therefore being 'selected' by the female"

I can imagine if you have a wife/girlfriend you had better check she hasn't left you a handwritten note on the kitchen table and gone out to find a man sensitive to a womans needs rather than interested in the minutiae of film sensitivity and digital resolution. It's clearly evident from the time you guys have spent in front of your computers trying to demonstrate who's theory is right that you need to get out more!

danielleetaylor · November 16, 2008

What's so hard to understand about a "theoretical upper bound"? It means you can't get better - you

certainly can get worse.

Under your theory it would not get much worse until contrast reached very low levels. If each grain rendered a

gray tone, then black/white or gray/gray would matter little until contrast reached very low levels. Film's

resolution would be like digital and drop off very slowly.

Also, do you mean to say that with digital, resolution at grayscale targets is the same as for

monochromatic targets then?

It drops off at a much slower rate than with film. Compare the shadow detail of a digital image with a film

image of the same scene at the same exposure.

Rich Evans posted an SEM micrograph of a single crystal of TMax 400 that is at least 10 microns in the

dimension seen. Here's another: from Kodak - also 10 microns, although they don't say which film.

Here are shots from a PDF I have that show cyrstals in the range mentioned. I guess it depends on the film.

Vijay, I have one question I wish you would answer: why do we never observe gray grains?

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