Wow - read this re: Film versus Digital debate!

[rishij]

Well, Vijay, before I put forth any further answer, can you or somebody tell me how many sensitivity sites usually

exist per grain?

 

I'm trodding carefully right now :)

 

Furthermore I have to finish reading the rest of your posts before I concur that we're in agreement :)

 

Rishi

[danielleetaylor]

<P>Sigh...</P>

<P></P>

<P><i>That those silver specks you see under a microscope must be subgranular structures - that a single crystal

site isolated by gelatin could have several of these - thereby creating a "halftone grain as in halftone in the

same AgBr crystal site"</i></P>

<P></P>

<P>Most of those silver specks you see under a microscope are super granular structures, silver deposited from

more than one silver halide crystal. Even where you observe just one, it is black. The structures within an

individual grain, seen under an electron microscope, are too small to render tone. They don't pass light. Single

silver halide crystals isolated by gelatin may develop out to different sized silver deposits, but all the

deposits, if they can be seen at all, will be seen as black. <i>That's why a grain is not like a pixel, and why

we do not observe gray grains.</i></P>

 

<P><i>At this point, Rishi, you and I are in agreement about everything except that you haven't said that

Reichmann is wrong. So do you agree then that Reichmann's film resolution estimate results in too low a

number?</i></P>

<P></P>

<P>Reichmann didn't provide any estimate of film resolution in his article. It's pointless to theorize about film

resolution. Shoot a chart and measure it directly. At 1.6:1 contrast most films are done by 60 lpmm. Expect a

lower number for detail that covers a range of tones rather than pure black on pure white.</P>

[vijay_nebhrajani]

Can we argue Canon vs. Nikon now? ;-)

 

You're on man: Nikon makes better glass - in fact so good that can resolve the two stars in a binary star system (on a clear night of course). Canon can't do that. In fact, Canon glass can't even resolve two oranges hanging five inches apart on a tree ten feet away as two separate objects. All I get is a single orange colored blob.

[vijay_nebhrajani]

Daniel: "Most of those silver specks you see under a microscope are super granular structures, silver deposited from more than one silver halide crystal."

 

Aren't those crystals isolated in space from one another? How did they become a super granular structure? Wouldn't those specs then be huge - something in the order of 50 microns linearly (only 10 5 micron grains need join together to become a super granular structure, easy enough)? Isn't 50 microns visible to the naked eye? After all a human hair is about 50 microns thick.

 

These super granular structures are also all black (no tone) - so tone must then be made of clusters of super granular structures?

[bernardwest]

<i>OK, so if I somehow take identical crystals and make film out of it, it will behave differently than regular film then?</i><p>

 

I suspect so. And what does this prove?<p>

 

<i>We must have crystal variance to make photographic film?</i><p>

 

No idea. And this is relevant how?

[vijay_nebhrajani]

Daniel: Reichmann didn't provide any estimate of film resolution in his article.

 

You're right and I'm sorry. I should have said "Reichmann's assumption that grain is binary results in too low a theoretical upper bound for the resolution of film."

 

Oh, I repeated that ad nauseum already?

[vijay_nebhrajani]

@ Bernie West, Nov 14, 2008; 03:25 a.m.

 

"I suspect so. And what does this prove?"

 

"No idea. And this is relevant how?"

 

Just a yes or no answer will do. The binary grain theory implies these, so I was just trying to confirm.

[nhut-nguyen]

Geeze...Give it up folks, and go shoot some photos.

[rishij]

"We must have crystal variance to make photographic film?"

 

Well, the variance gives a larger dynamic range to the film.

 

Think about it: let's say, for argument's sake, we're using an area of about 500 grains to represent thousands of tones. If every crystal got just as easily exposed, the dynamic range recordable would be very small. For example, it'd take a little bit of light to expose 10 grains, and a moderate amount of light to expose all 500. But now make 100 of those grains very hard to expose. Then, the little bit of light would still presumably expose 10 higher sensitivity grains, but it'd take more than a moderate amount of light to expose all 500 grains, since 100 of them now are lower sensitivity.

 

We should probably re-hash some of this stuff at a later date. Not now. In answering the question 'what's the real resolution of film across both high contrast & low contrast scenes', the real interesting question is not how many tones are representable by a single grain, but how many tones are representable by an 'area on the film' on the order of the size of a grain. Probably not that many. Many more tones would be discernible in and around the area of 500 grains. And tone is created supra-granularly... but, yes, I don't think the filaments can clump across grains b/c there's gelatin in between. But viewed from a distance, a dense area could appear as clumps, sure. The proof? Fully exposed film looks black, yet has clear areas in between the grains where the gelatin is! Right?

[danielleetaylor]

<P><i>Geeze...Give it up folks, and go shoot some photos.</i></P>

<P></P>

<P>Believe it or not, this is actually an interesting conversation for those of us in the middle of it, and it

has forced me to look up and read some old articles and texts which refreshed my memory about the technical

aspects of B&W film. </P>

<P></P>

<P>Besides, I'm too sick to go outside and shoot right now. In 2-3 more days I hope to be pretty much over this

demon spawn of a cold...</P>

[danielleetaylor]

<P><i>Aren't those crystals isolated in space from one another?</i></P>

<P></P>

<P>Not necessarily. I don't see why you couldn't end up with lots of crystals in the same plane touching or

nearly touching. At any rate, remember that film is a 3D structure with grains overlapping each other but on

different planes. That's why under a microscope many grains are out of focus.</P>

<P></P>

<P><i>How did they become a super granular structure? Wouldn't those specs then be huge - something in the order

of 50 microns linearly (only 10 5 micron grains need join together to become a super granular structure, easy

enough)?</i></P>

<P></P>

<P>Attached is the 400x microscope image with a square block next to it. That block represents 10x10 microns.

Silver halide crystal size in B&W film is 2 microns or less. (I don't think there's a substantial change in size

after it's converted to silver, but I could be wrong. I'll try to find out.) Most of the individual specks you

see in that view are larger than 2 microns. And the large black area appears solid black. Whether they're

touching (same plane) or overlapping in 3D space, most of those black blobs are super granular.</P>

<P></P>

<P><i>These super granular structures are also all black (no tone) - so tone must then be made of clusters of

super granular structures?</i></P>

<P></P>

<P>I think it's fruitless to try and pin it down too accurately. You have grains and grain blobs mixed in with

clear space. At a distance we see this variable density of silver as tone.</P><div></div>

[bernardwest]

<i>Vijay Nebhrajani , Nov 14, 2008; 03:34 a.m.<p>

 

@ Bernie West, Nov 14, 2008; 03:25 a.m. <p>

 

"I suspect so. And what does this prove?" <p>

 

"No idea. And this is relevant how?" <p>

 

Just a yes or no answer will do. The binary grain theory implies these, so I was just trying to confirm.</i><p>

 

I"m still not sure of what your argument is. How does it imply this? If you want to explain your whole reductio ad absurdum (raa from now on) to me again, I'm happy to debate you on this just for the sake of keeping the debate going.<p>

 

I will say though I find it amusing that you keep insisting you have proved Reichmann wrong. How exactly? Reichmann's premise was that film resolution isn't as good as digital. Like I said a thousand posts ago, disregard the use of the term "binary". It's a side issue. The real issue is RESOLUTION. By insisting that film has a greater resolution that digital you are by implication saying that film has tonal resolution of less than 5 or so microns. Why is it at 100 odd microns we only see black and white? Where are the tones? Tones don't become apparant (going by the Kodak images) until somewhere between 60 and 400x magnification. If I could be bothered to work it out, it would be at scales far greater than 5 microns. Digital has full tonal resolution down to it's pixel size (although clearly the anti-aliasing and bayer interpolation must effect this result). If you think that tones are visible at magnifications greater than this, then the impetus is on YOU to provide EVIDENCE. So far you and your cronies have provided none.<p>

 

By the way Rishi, that was an excellent summary. It was exactly what I was looking for to piece this all together.

[danielleetaylor]

<P><i>Attached is the 400x microscope image with a square block next to it. That block represents 10x10 microns.</i></P>

<P></P>

<P>I should say "...That block represents 10x10 microns at the same scale as the microscope view."</P>

[rishij]

DLT, you are just so damn cool. That picture with the scale 'square' next to it just made things so crystal clear for me. Oh, and hope you feel better soon.

 

Vijay, Bernie, Ron, Mark, everyone else -- great debate... everyone put a lot of thought into this & this is just amazing to see in an online community. Imagine, 20 years ago, how would I have had this debate? We're privileged to be able to come together in such fora, no matter what part of the world we're from, and learn from one another & push knowledge forward.

 

One analogy I like to apply here is the whole idea that the chemical process of film, kind of like biology & evolution, only cares for the end result. Evolution selects for 'whatever works'... in the case of film, same thing. Digital, designed from the ground up, is an entirely different approach. Each pixel, just 6.4 microns in size, can represent 16,384 tones. Because that's how we 'designed' it. Now look at the biology of things -- a mess, but whatever works. So much for the argument of 'intelligent design'. Doh, here we go again... my crusade against 'faith' and pro-rationality :) OK, I'll stop there.

 

The other thing that is apparent from this debate is the following:

 

We as scientists, or, shall I say, 'rationalists', are not afraid to let go of old tenets in favor of different ones, or new ones (in this case). We will argue, debate, back and forth, and then we will be convinced by the overwhelming evidence, though the evidence may contradict what we hold near & dear. But that's ok. That's part & parcel of being a scientist. Questioning. Questioning your very belief. Isn't that beautiful? Because when something more reasonable comes along, we welcome it (well, after 300 pages of debate). That way, we stay at the forefront. Isn't there something to be said about that?

 

Stated more clearly: Isn't there something to be said about our *lack* of faith, or our ability to replace faithfully held beliefs when presented with evidence for the contrary? This way, we can stay at the forefront of knowledge. Something you can't do if you just accept things on faith.

 

"Doh, here we go again... my crusade against 'faith' and pro-rationality :) OK, I'll stop there."

 

Oops, I didn't stop there :)

 

Cheers folks,

Rishi

[thirtyfive]

My favourite photographer, Perou, still shoots primarily on film, unless requested otherwise. There has to be a reason why so many pro's stick to the medium...

[vijay_nebhrajani]

Sorry (advance apologies to all whom I annoy) but I want to respond to some of what Daniel said:

<p>

Daniel: <i>Grains range from 0.2-2 microns. As I pointed out earlier most of the specks we might call a "grain",

even at 400x, are actually clumps of grains. Many individual grains are not large enough to even be observable if

they were standing alone, much less convey a tone based on filament gaps (most of which can't even pass light).

But multiple crystals in a region develop out and you see the black clump. The largest crystals developed out

would be just observable at 400x.</i><p>

 

The first statement puts a lower size bound on grains - 0.2 microns - a size easily detected by an optical

microscope (even if it were a bit fuzzy - <a

href="http://en.wikipedia.org/wiki/Optical_microscope#Limitations_of_light_microscopes">here's</a> the reference).

<p>

The next statements imply that the smallest developed grain is not even detectable by an optical microscope -

much smaller than 0.2 microns then.

<p>

You changed the definition of grain on me there didn't you?

<p>

Besides, if this is the case, then it can't be detectable by the naked eye, and thus can't contribute to the

formation of tone at all.

<p>

<i>You keep trying to argue from logic and theory. Theory must bend to observation.</i>

<p>

Ha. You imply that observation is the ultimate truth. Yeah right; we observe daily that the it is the sun that

rises and sets, yet this is a heliocentric planetary system. <p>

Your observations could be flawed simply because you are seeing bright light through a microscope which might be

exceeding the dynamic range possible for your eye, meaning that gray could appear black. After all it is for this

very reason that we see the moon as white; even though it is actually grey. The same holds for those pictures you

posted.

<p>

Or you could be seeing gray specks and dismissing them as being out of focus. Mind you, I'm not saying that

either of these is the case so don't attack me over it; I'm saying if such were the case you would be basing your

theory on a flawed observation.

<p>

You'll have to do better than that if this is your idea of "experimental evidence". When you show me some

incontrovertible experimental evidence, I'll think about bending the theory. No sooner.

<p>

<i>It is what I have been talking about as well. But A vs. B is not relevant.</i><p>

Sure it is. One is a physical impossibility. Not theoretical, not logical, but a physical impossibility. If you

assume a physical impossibility to be true, you get into the domain of the absurd.

<p>

<i>Once a cluster of them becomes large enough in both length and width to be optically observed it will be

observed to be a single black particle even though electron microscopes reveal a more complicated structure.</i>

<p>

That is quite absurd. You imply that as soon as the size of a grain becomes less than some threshold it won't be

optically observable, but clusters of these will block light just fine, i.e., work just fine as an optical

attenuator. Of course, the distance between such grains has to be larger than 0.4 microns (wavelength of light)

because if somehow another of those really tiny grains got inside a 0.4 micron gap between two other tiny grains,

this structure of 3 really tiny grains will become completely opaque (smaller gap than wavelength).

<p>

This means that if I ever make a film with really fine grain - smaller than 0.1 microns even - I must keep those

grains more than 0.4 microns apart, somehow, because otherwise the film simply wouldn't pass light as soon as

those grains developed - to any size. And yet, if I did manage to clump them close enough so that they formed a

super granular structure, they would start passing light again, tones would reappear, and everything would be

fine again.

<p>

Daniel, every time you come up with a theory of what may be happening, I come up with the absurdities it causes.

Won't you come around to accepting that a single grain must act as a light attenuator by itself, i.e., not be

binary - clear or opaque?

<p>

<i>Silver atoms (plural) on film are in a solid state, and solid silver is most definetly opaque.</i>

<p>

And yet Rich Evans provided an example of a 20 angstrom gold film sputter uniformly coated with gold - which is

optically transparent. His quote: "Any solid material at the atomic level is not 'opaque' to light - sputter-coat

a 20 angstrom film of gold onto glass and tell me what you see." Now you can do that (astronauts helmets for

instance - 500 angstrom gold film on the visor) experimentally, so this is not some pie in the sky theory. See <a

href="http://www.utilisegold.com/assets/file/utilisegold/pdf/Langley_4_4.pdf">this</a> document.

<p>

Its like this: a single atom thick film of silver is transparent - as you go on increasing its thickness, it

starts attenuating the amount of light passing through it, until at some thickness, it attenuates all the light,

effectively becoming opaque. Those silver filaments behave like that. It is immaterial that the interfilamentary

gap is smaller than the wavelength of visible light - light will behave as particles (photons) that won't be

completely obstructed by silver atoms if the silver atoms don't form a thick enough layer - thus, the silver

filaments will act like an attenuator (some photons get absorbed, some pass through), giving you grayscale at the

granular level.

<p>

In fact, if it didn't have grayscale, and were only fully opaque - there would be no point stacking grain in the

third dimension, would there? Because then as soon as a grain developed (to fully opaque), it would occlude all

grain behind it. And any grains that happened to lie too close to each other - not touching, mind you, just

closer than the wavelength of light would immediately turn the whole area opaque. Which means you couldn't really

make tones like zone 1 or 2 because like dark gray must have densely packed grain - perhaps even smaller than the

wavelength of light and become black. Drat.

<p>

Since you don't seem to like abstract proofs like reductio ad absurdum, I just explained the physical process of

how grain must have tone and what madness follows if it didn't.

[a8459a2]

The only thing that really irks me in these debates is comparing standard DSLR's to hasselblads and the like (after saying 35mm is an amateur format so they will compare DSLRs to medium format for a more even comparison) when it is not at all equal. If you are going to compare a medium format film camera to a digital, try and find the digital equivalent of medium format. A 6megapixel nikon versus a medium format hasselblad isn't a real comparison. Now a 39megapixel hasselblad versus a medium format hasselblad...that is a comparison I would like to see. I want to see a D80 compared to an N80 for once.

[fotolopithecus]

You Guys can't be serious about comparing any of these images, one taken at night, one in the day, one of rocks& water, one of a building. All things must be the same, exactly, same camera lens, same scene, same time, same tripod, same iso, etc, etc, etc.

[vijay_nebhrajani]

On an unrelated note - this thread has over 417 posts - can we find out if it is the longest thread on photo.net ever? Or even better, can we figure out if it has the most words ever written on PN?

[a_petkov]

If everyone here spent the same and energy taking pictures instead of debating what's better (what a pointless debate) they would be better photographers and wouldn't care if they shot digital film or whatever.

[bike tourist]

One more aspect: As one who has bridged the gap between the old film stock agencies and their new digital cousins, be prepared for a shock. You will probably have to accept pennies instead of dollars for your work. The market is constantly heading downward, being diluted by ever-increasing millions of images.

 

Not all stock agency reviewers are knowledgable. Most will equate any film grain with "noise" and they will recoil in shock by any suggestion of such. They demand clean, front lit, boring images with no hint of enterprise or deviation from what they think their customers want. You can make a little money from stock these days if you agree with the parameters the agency sets and you are prepared to keep feeding the beast with a steady stream of images.

[bernardwest]

<i>(what a pointless debate)</i><p>

 

What a pointless post. Why did you even bother?<p>

 

From my point of view, I have learnt a lot from this thread.

[gallery]

"

Can't wait to read some opinions!

-- philip sutton

"

LOL are you still here?

[vijay_nebhrajani]

And if any of you binary grain folks need more convincing, you should figure out how many tones can be formed by

4 grains that can either be opaque or clear - 16? Wrong. Only 5 - all grains clear, one grain opaque, two opaque,

three opaque, all four opaque. It doesn't matter which three are opaque, the tone is the same - 75% gray.

 

So to form say the equivalent of a digital pixel, which has 2^16 tones for just one color, you'd need (2^16 - 1)

binary film grains; or 65,535 grains. The film pixel that this would form would occupy an area of 256x256 binary

pixels, or at a 2 micron grain size, an area in the neighborhood of 500 microns x 500 microns, or 0.5mm x 0.5mm.

 

By this reasoning, of course a color film pixel would be nearly 1mm x 1mm assuming dye clouds are roughly as

small as silver halide grain. Of course, if the dye clouds were bigger, the film pixel would be even larger.

 

And the crazy thing about this not even that: it is that as you go to larger area, you can resolve more tones, so

as you go smaller, the tone of your image would change. For color film, the color would change as you saw the

film with a 5x loupe and then went to a 10x loupe. Yeah, with 1mm x 1mm pixels, you don't need more than 5x or

10x magnification to see individual pixels. Heck, you don't need magnification at all. All you'd have to do is

bring the film closer to your eyes and observe the colors change.

 

Reductio ad absurdum anyone?

[vijay_nebhrajani]

And here's more - because I am enjoying myself thoroughly now:

 

Dye clouds are transparent, right? I mean, if they were opaque, there couldn't exist such a thing as color slide film.

 

So then, in B&W chromogenic film, the image is formed by transparent, or rather, grayscale dye clouds. So one dyecloud (maybe somewhat larger than a traditional silver grain) - must be capable of representing continuous tone. So the resolution of chromogenic (C41) B&W film must be orders of magnitude better than traditional silver halide film, right?

 

And color film, by the same logic would also so far outresolve silver halide film it wouldn't even be funny, yes? It wouldn't be as good as C-41 B&W, but it would leave silver halide in the dust.