peripatetic
Well-known
For the scanning gurus.
I mostly use the C41 BW films, Ilford XP2 and Kodak BW400CN.
Because:
I am (still) considering purchasing a MF outfit, and because I can't afford a Coolscan 9000 am wondering what resolution scans I should pay for. The labs seem to base their prices on the final output size (I guess they have to base it on something), but clearly there is no point in paying for a 100Mb scan when a 20Mb scan will do the same job with the film I happen to be using.
So here is my question: At what point does one reach severely diminishing returns with a given film type?
Is there any point in scanning XP2 at 4000dpi? Will everything beyond 2000dpi be just extra grain/noise? My intuition says that for ISO400 films there is probably little extra detail in the 4000dpi scan compared to a 2000dpi scan. With Velvia50 I would expect there is extra detail beyond even 4000dpi.
Does anyone have a handy matrix for optimum scan resolutions for different film types? [Or have I just got hold of the wrong end of the stick with this notion?]
It also has longer term purchasing implications, for example if I do 90% of my shooting with BW ISO 400 films (C41 or silver), it may be that there is no real point in getting a Coolscan9000 over a V750 for example. The V750 is reported as having a 2500dpi optical resolution, if the film only needs 2000dpi then I can spend the money I might have spent on some extra lenses, or a holiday, gift for the wife, etc.
Thanks in advance.
Craig
I mostly use the C41 BW films, Ilford XP2 and Kodak BW400CN.
Because:
- 400 ISO
- Easy to get processed in a high-street lab.
- Allegedly good for scanning.
I am (still) considering purchasing a MF outfit, and because I can't afford a Coolscan 9000 am wondering what resolution scans I should pay for. The labs seem to base their prices on the final output size (I guess they have to base it on something), but clearly there is no point in paying for a 100Mb scan when a 20Mb scan will do the same job with the film I happen to be using.
So here is my question: At what point does one reach severely diminishing returns with a given film type?
Is there any point in scanning XP2 at 4000dpi? Will everything beyond 2000dpi be just extra grain/noise? My intuition says that for ISO400 films there is probably little extra detail in the 4000dpi scan compared to a 2000dpi scan. With Velvia50 I would expect there is extra detail beyond even 4000dpi.
Does anyone have a handy matrix for optimum scan resolutions for different film types? [Or have I just got hold of the wrong end of the stick with this notion?]
It also has longer term purchasing implications, for example if I do 90% of my shooting with BW ISO 400 films (C41 or silver), it may be that there is no real point in getting a Coolscan9000 over a V750 for example. The V750 is reported as having a 2500dpi optical resolution, if the film only needs 2000dpi then I can spend the money I might have spent on some extra lenses, or a holiday, gift for the wife, etc.
Thanks in advance.
Craig
rogue_designer
Reciprocity Failure
with 35mm, I would maintain that a 4000dpi scan is still the benchmark, even with higher speed films. Your resolving the grain in more detail, true, but that only shows as "more grain" if you over enlarge.
But they use output size as the guide for a reason. The resolution you need is entirely dependent on the size you intend to print.
In my opinion.. If you won't print larger than 11x14/13x19, you don't need the Coolscan 9000 - the 750 will perform admirably. But it will start to suffer in comparison on larger prints.
But they use output size as the guide for a reason. The resolution you need is entirely dependent on the size you intend to print.
In my opinion.. If you won't print larger than 11x14/13x19, you don't need the Coolscan 9000 - the 750 will perform admirably. But it will start to suffer in comparison on larger prints.
bmattock
Veteran
In practical terms, there are too many variables to make specific statements about which DPI will be good and which will be overkill for any particular emulsion. The lens, the scene, and the capabilities of the scanner in question all enter into it.
Generalized statements might be:
1) More DPI is better than less.
2) There is a point of diminishing returns, but one seldom knows until one explores it personally what that might be.
3) Medium format and larger film requires less intensive scanning.
4) Dedicated film scanners do a better job than flatbed scanners, everything else being equal, due to DMax and DMin, as well as speed.
That said, there are plenty of flatbed scanners which do a perfectly acceptable job. If you are going to be scanning a combination of 35mm and MF, it might be the best way to go in general, especially if you're on a budget. If you intend to scan LF, you may not have any real choice.
My personal choice has been a ScanDual IV (no longer made) and an Epson 4490. No complaints so far. I'd love to have 'better' quality scanning kit, but at the price point I paid, I believe I've done well.
Generalized statements might be:
1) More DPI is better than less.
2) There is a point of diminishing returns, but one seldom knows until one explores it personally what that might be.
3) Medium format and larger film requires less intensive scanning.
4) Dedicated film scanners do a better job than flatbed scanners, everything else being equal, due to DMax and DMin, as well as speed.
That said, there are plenty of flatbed scanners which do a perfectly acceptable job. If you are going to be scanning a combination of 35mm and MF, it might be the best way to go in general, especially if you're on a budget. If you intend to scan LF, you may not have any real choice.
My personal choice has been a ScanDual IV (no longer made) and an Epson 4490. No complaints so far. I'd love to have 'better' quality scanning kit, but at the price point I paid, I believe I've done well.
Pherdinand
the snow must go on
I've printed a 50x60 cm (i.e. 20x24") frame from acros 100 35mm, that i scanned on the epson v700 flatbed. Although sharpness might not be critical in that subject matter, there is absolutely no need for higher resolution in that image!
I scanned the same frame on the minolta dual IV and there was absolutely NO gain in sharpness.
With slides, it's a different story. Dark areas get noisy way too fast with the flatbed.
I scanned the same frame on the minolta dual IV and there was absolutely NO gain in sharpness.
With slides, it's a different story. Dark areas get noisy way too fast with the flatbed.
Pherdinand
the snow must go on
i forgot to add: i scanned at 3600 dpi and upscaled it to the needed printing pixel size. Scanning at nominal 4800 or higher resolutions made no sense at all.
Moreover, at the touted 6400 dpi film-scan resolution, the epson produces some weird pixelation so it is actually BETTER to scan lower rez and enlarge.
Moreover, at the touted 6400 dpi film-scan resolution, the epson produces some weird pixelation so it is actually BETTER to scan lower rez and enlarge.
mfogiel
Veteran
There are 2 considerations to make:
- at which ppi are we extracting all the information from film
- what is the "optimum" size of your files
If you sift through internet, you will find that most agree even moving from 4000ppi to 6000ppi still shows more information, and others say only 8000ppi really covers it all.
Having said this, let's see it from the other end: how big quality prints do you need?
Some reckon printing at 720 dpi is better than printing at 400dpi. etc, but as far as I am concerned I have decided to stop at 360 dpi, and even 300dpi is perfect most of the time. The height of a 24x36mm neg is roughly equal to 1 inch , so if you need to print 11 inch high (without cropping), you need a magnification of 11 times, that gives you 360*11=3960, at 16 times (for a 16x20) you need 360*16=5760, so depending on the size of the print, if you need the maximum quality ( same sort of thing you expect from Leica gear, BTW) you have to decide.
From my experience, if you are shooting frequently, the cost of a CS 9000 pays itself back in a few months against using a lab capable of a properly done 4000ppi resolution scans.
- at which ppi are we extracting all the information from film
- what is the "optimum" size of your files
If you sift through internet, you will find that most agree even moving from 4000ppi to 6000ppi still shows more information, and others say only 8000ppi really covers it all.
Having said this, let's see it from the other end: how big quality prints do you need?
Some reckon printing at 720 dpi is better than printing at 400dpi. etc, but as far as I am concerned I have decided to stop at 360 dpi, and even 300dpi is perfect most of the time. The height of a 24x36mm neg is roughly equal to 1 inch , so if you need to print 11 inch high (without cropping), you need a magnification of 11 times, that gives you 360*11=3960, at 16 times (for a 16x20) you need 360*16=5760, so depending on the size of the print, if you need the maximum quality ( same sort of thing you expect from Leica gear, BTW) you have to decide.
From my experience, if you are shooting frequently, the cost of a CS 9000 pays itself back in a few months against using a lab capable of a properly done 4000ppi resolution scans.
Svitantti
Well-known
Fast films have bigger grain, yes... But they also have small grain there. This is what actually gives film the dynamic range (at least one reason to it). Bigger grains will be activated first (least light), because moro photons hit them. Smaller grain (slower film) will take more light and this is why the highlights wont blow out so easily.
So I would say there is not much sense dropping the resolution if you want to capture what really is in the film, as well as possible.
So I would say there is not much sense dropping the resolution if you want to capture what really is in the film, as well as possible.
Pherdinand
the snow must go on
I'm sorry but let's avoid confusion here, shall we.
GRAIN in traditional black and white photography results from the small gaps that appear in the emulsion between the silver crystals.
Bigger grains mean bigger gaps. Although their size can be associated somewhat with the real size of the silver crystals, it is NOT the same. The silver crystals are MUCH smaller.
Grains don't get exposed by the light, therefore. Grains are holes that let the light through and are only present after development.
If you don't believe it, ask yourself why grain is black on a negative that was already inverted to positive.
Regards!
GRAIN in traditional black and white photography results from the small gaps that appear in the emulsion between the silver crystals.
Bigger grains mean bigger gaps. Although their size can be associated somewhat with the real size of the silver crystals, it is NOT the same. The silver crystals are MUCH smaller.
Grains don't get exposed by the light, therefore. Grains are holes that let the light through and are only present after development.
If you don't believe it, ask yourself why grain is black on a negative that was already inverted to positive.
Regards!
Svitantti
Well-known
Hmm. What is a negative that is already inverted to positive? And is grain black or white or both?
The developer acts with exposed grains and makes them "black" on the negative. The fixer removes unoxposed part of the silverbromide. So the grain on the negative is black and on a print it is white.
Does this have something to do with this topic? I dont know... Still there are small and big grain mixed in any fast film and the biggest grains are missing in slow films emulsion.
peripatetic
Well-known
Okay, so I think I have gone some way to discovering the answers to my questions.
Norman Koren's pages about MTF are very useful...
http://www.normankoren.com/Tutorials/MTF1A.html
And looking at the comparative MTF graphs from the Kodak website it seems clear that BW films, have superior sharpness to Velvia 100 slide film. This may not be a surprise to most of you, but it was to me.
BW400CN has a very similar sharpness to Velvia 100. T-Max 100 and 400 are much sharper than Velvia, and even T-Max 3200 is as sharp!
BW400CN tech specs...
http://www.kodak.com/global/en/professional/support/techPubs/f4036/f4036.pdf
TMax films...
http://www.kodak.com/global/en/professional/support/techPubs/f4016/f4016.pdf
This helps for comparative purposes because there are lots of resources about how much detail there is available in scans of Velvia.
In the Norman Koren page he makes it clear that there is extra detail to be gained from 8000dpi scans over 4000 and 2400.
http://www.normankoren.com/Tutorials/Scan8000.html (Scroll to the bottom of the page.)
So the basic answer to my question is that there is extra detail to be had from a negative all the way down to 8000dpi, so get the best scanner you can afford. Clearly from the Norman Koren article appropriate sharpening must be applied, as a well sharpened 2400 image is almost as sharp as an unsharpened 4000 image.
Addressing the practical issues however, there is a point where you have to say that you have enough resolution for your purposes. (And this has been the thrust of the excellent comments above!)
Consider 3 price points:
1. Epson V750 -> £400 (2400dpi optical)
2. Coolscan 9000 -> £2200 (4000dpi optical)
3. Hasselblad Flextight X1 -> £8000 (6400dpi 35mm, 3200dpi 60mm)
4. esoteric... and £stratospheric
So on 60mm film @ 2400dpi we get 5640 pixels.
5640/300 -> 19 inches
5640/240 -> 24 inches
In practical terms I think that is going to be big enough from a 6x6 or 6x7 negative for 99% of my prints. For the other 1% I can fork out for a drum scan.
For 35mm work I have my Coolscan V ED, which is working out fine up to 8x12, and starts to break up a bit at 12x18 depending on the image.
So moving up to 6x7 + V750 with current workflow should provide pretty good 24x28 images; probably rather better than my current 12x18 from 35mm. If I can find a way to afford it however, the Coolscan 9000 would seem to hit a pretty good price/performance point for 6x7.
Norman Koren's pages about MTF are very useful...
http://www.normankoren.com/Tutorials/MTF1A.html
And looking at the comparative MTF graphs from the Kodak website it seems clear that BW films, have superior sharpness to Velvia 100 slide film. This may not be a surprise to most of you, but it was to me.
BW400CN has a very similar sharpness to Velvia 100. T-Max 100 and 400 are much sharper than Velvia, and even T-Max 3200 is as sharp!
BW400CN tech specs...
http://www.kodak.com/global/en/professional/support/techPubs/f4036/f4036.pdf
TMax films...
http://www.kodak.com/global/en/professional/support/techPubs/f4016/f4016.pdf
This helps for comparative purposes because there are lots of resources about how much detail there is available in scans of Velvia.
In the Norman Koren page he makes it clear that there is extra detail to be gained from 8000dpi scans over 4000 and 2400.
http://www.normankoren.com/Tutorials/Scan8000.html (Scroll to the bottom of the page.)
So the basic answer to my question is that there is extra detail to be had from a negative all the way down to 8000dpi, so get the best scanner you can afford. Clearly from the Norman Koren article appropriate sharpening must be applied, as a well sharpened 2400 image is almost as sharp as an unsharpened 4000 image.
Addressing the practical issues however, there is a point where you have to say that you have enough resolution for your purposes. (And this has been the thrust of the excellent comments above!)
Consider 3 price points:
1. Epson V750 -> £400 (2400dpi optical)
2. Coolscan 9000 -> £2200 (4000dpi optical)
3. Hasselblad Flextight X1 -> £8000 (6400dpi 35mm, 3200dpi 60mm)
4. esoteric... and £stratospheric
So on 60mm film @ 2400dpi we get 5640 pixels.
5640/300 -> 19 inches
5640/240 -> 24 inches
In practical terms I think that is going to be big enough from a 6x6 or 6x7 negative for 99% of my prints. For the other 1% I can fork out for a drum scan.
For 35mm work I have my Coolscan V ED, which is working out fine up to 8x12, and starts to break up a bit at 12x18 depending on the image.
So moving up to 6x7 + V750 with current workflow should provide pretty good 24x28 images; probably rather better than my current 12x18 from 35mm. If I can find a way to afford it however, the Coolscan 9000 would seem to hit a pretty good price/performance point for 6x7.
Pherdinand
the snow must go on
Sorry, you are simply wrong.
Grain is formed by the gaps appeaing between the silver crystals and, therefore, in the negative grains are holes i.e. white. Whne you invert it (or make a print), they are black.
This is not a is-the-zebra-black-stripes-on-white-or-white-strips-on-black thing. This is better defined.
What it had to do with the topic? Maybe nothing, but as somebody brought up the subject and gave a wrong idea about grain, i thought to correct it, eventually.
Here it is, strongly magnified negative, and inverted. What is black and what is white?
Svitantti
Well-known
So are you saying there are no grains in the film emulsion before it is exposed and developed? What determines the size of the grain if there are no grains in the film at first? How do films have different ASA speed?
Even if this is as you say, why would grain be the "holes" between the grains and not the silver grains?
Pherdinand
the snow must go on
Dear Svitantti,
"why would" is not a question i can answer
The "grain" we see and that gets bigger and more visible with increased film speed and agitation and and and, is = gaps between the much much smaller silver crystals.
Third time i write this.
There are plenty of stuff i don't know; this one i happen to have read, learned and seen with my own eyes on my own material.
I see there is no way to convince you so i point your attention to any book (a good read is "Schroeders Negativ Praxis", you can even find it tri-lingual: english,german,italian) or proper description that treats the photochemical process(ing) on this level - or simply to a microscope and a piece of film.
Perhaps you are not even so interested in it. That's also fine.
But please do not claim untrue things, for people might believe it.
Regards
"why would" is not a question i can answer
The "grain" we see and that gets bigger and more visible with increased film speed and agitation and and and, is = gaps between the much much smaller silver crystals.
Third time i write this.
There are plenty of stuff i don't know; this one i happen to have read, learned and seen with my own eyes on my own material.
I see there is no way to convince you so i point your attention to any book (a good read is "Schroeders Negativ Praxis", you can even find it tri-lingual: english,german,italian) or proper description that treats the photochemical process(ing) on this level - or simply to a microscope and a piece of film.
Perhaps you are not even so interested in it. That's also fine.
But please do not claim untrue things, for people might believe it.
Regards
Svitantti
Well-known
This is exactly what it is...
In the first place I did not even claim anything that you started speaking of. And for second, that actual grain in the negative is black and is silver. The non-grain is clear filmbase which is not called grain. In a positive image formed from the negative, the white parts are the grains on the negative and vice versa, yes... And the black parts are the metallic silver grain of the paper, if the print is done by traditional wet printing.
The size of the metallic silver grains also grows when film speed is increased. It is true that the gaps in between them grow too, but this does not mean the gaps are the grain.
Fact is, that the size of the grain is determined when the emulsion is produced. The sensitivity of the film is determined by the size of the grains in the emulsion (or more accurately the distribution of course). Not by the size of the gaps, because the gaps are not sensitive to light. Sure you could make a film with very few grains and big gaps, but theres no sense in such film.
The image is formed by developing exposed grains. They are what appear in the negative as black (grains). Without those grains, there is no image (process the film without developer, you get no grains or as you would say, one very large grain
).If you want, you can say grain (in the final product, positive image) is the gap between the metallic silver grains. This is just like the zebra-case. But on the negative, the grain is the grain, not the gaps.
russianRF
Fed 5C User
Wikipedia says, "Film grain or granularity is the random optical texture of processed photographic film due to the presence of small grains of a metallic silver developed from silver halide that have received enough photons."
Wikipedia isn't necessarily always right, but if a fact has made it to Wikipedia, I think it's generally acceptable that many intelligent people believe it. The way the Wikipedia article is worded, I get the impression that the grain is indeed produced by the silver grains. I got that impression reading Ansel's "The Negative" as well...
I'm not saying you're wrong, Pherdinand. Is there somewhere online that backs up your claim about film grain being "holes" between the silver molecules?
Wikipedia isn't necessarily always right, but if a fact has made it to Wikipedia, I think it's generally acceptable that many intelligent people believe it. The way the Wikipedia article is worded, I get the impression that the grain is indeed produced by the silver grains. I got that impression reading Ansel's "The Negative" as well...
I'm not saying you're wrong, Pherdinand. Is there somewhere online that backs up your claim about film grain being "holes" between the silver molecules?
Svitantti
Well-known
It is just a matter of how you think about it. Like with zebras . And in case of the final positive image, because...
In the negative, the grain logically is the metallic silver, and not "the space between the things (grains)".
. And in case of the final positive image, because...In the negative, the grain logically is the metallic silver, and not "the space between the things (grains)".
Pherdinand
the snow must go on
Dear Svitantti again,
The stuff i was saying is not "to say what I want to say". I am sorry but it IS the correct and only definition of that visible grain in the film. What is CALLED grain on a film in photography, and what is pointed out, referred to, as big or small grain, visible grain, smooth grain, beautiful grain, ugly grain and popcorn grain, golfball size grain, is the gaps between the clumped-together tiny little silver crystals. These gaps can be big enough to be visible by a magnification of less than 10 times, depending (yes) on film type AND depending a lot on the development procedure which you seem to forget above.
Indeed it would make more sense to say that grain is black in the film and it is the silver crystals...except that, it is NOT what we see. Silver crystals are extremely small, they clump together to form the dark part of the image in the emulsion, and the small gaps between them are the grains. The gaps can be smaller and more uniformly distributed, giving smaller visible grain on magnification, or can be coarser, bigger holes. The black silver crystals however NEVER show up separated, never form individually visible crystals, they are just a lot of them small *******s clumped together, in three dimensions (thus not only one single layer).Many many of these crystals lying ABOVE each other form a thick layer of opaque clumps and make a negative region very dense. This will give the highlights when inverted. If they are forming a less thick layer because received less light and most of them stayed as silver halide and were washed out from the emulsion, the negative will be "thinner" i.e. more transparent. Where there was no light at all, most of them do not reduce to metallic silver, almost all is cleared out and film gets highly transparent.
In the ideal case, the silver crystals are very small and very uniformly distributed in size and position and the layer they form is very uniformly getting optically thicker or thinner, leaving a grain-free look when magnified. However this can only happen when the silver crystals are extremely small and tight packed enough not to leave small gaps between them. Normally there ARE gaps between them which lets light through where it should not let light through. This gives the grain that appears under relatively low magnification and is white i.e. transparent. Projected + magnified on paper, it is black, no matter what the papers' resolution or granular structure is.
Think about it like this: Throw in a jar a bunch of small semitransparent glass balls. If they are very very small, they will fit very tightly and you get a uniform transparency of the "layer" if you look through it from the top. The level of opaqueness will be determined by how thick is the layer and how transparent are the balls. Now, if you increase the ball size, you will get less tight packing of them and eventually, the transparency of the layer will not be uniform, you will see gaps when you look through it. In the case of big big balls, i.e. big silver crystals, which are indeed determined by film type AND development, no matter how opaque the balls are there will always be gaps between them unless you stack a real thick layer, or you cleverly change the balls into something that fit better and leave no gaps, like, the famous t-max or Acros or Delta films have flat silver crystals that fit tighter than traditional 3D-shaped ones.
However you will never be able to discern the individual balls i.e. the individual silver crystals, these will always be clumped together and way too small individually - unless you have only a few in the jar and a really strong magnification, of course.
There is a clear definition of grain, as i said it's not the zebra thing.
Did you actually take a look on the image i posted above? The image is a digitally recorded magnified piece of film (negative) through a microscope, inverted digitally to positive. Has nothing to do with paper image grains.
The grains are black. Obviously, since the image is inverted, the grains in the piece of films were W H I T E.
I mentioned a professional book above. I quote from it:
"It is the gaps that result in grain showing in the print." Page 15. There are even some nice illustrations.
Wikipedia does not contradict what i say. It says, the grains are due to the presence of small grains of a metallic silver ,which is true - EVERYTHING in the imaging process is due to the silver crystals. Wiki does not say, however, that the grain visible in magnifications is these silver crystals, which they are not.
So, that's it, i can't say more obviously; you either believe it or look it up or forget it all and keep thinking that you can see the silver crystals growing in the new years' afternoon light
edit:here it is,further magnified, the nose of the dude (and inverted).
The stuff i was saying is not "to say what I want to say". I am sorry but it IS the correct and only definition of that visible grain in the film. What is CALLED grain on a film in photography, and what is pointed out, referred to, as big or small grain, visible grain, smooth grain, beautiful grain, ugly grain and popcorn grain, golfball size grain, is the gaps between the clumped-together tiny little silver crystals. These gaps can be big enough to be visible by a magnification of less than 10 times, depending (yes) on film type AND depending a lot on the development procedure which you seem to forget above.
Indeed it would make more sense to say that grain is black in the film and it is the silver crystals...except that, it is NOT what we see. Silver crystals are extremely small, they clump together to form the dark part of the image in the emulsion, and the small gaps between them are the grains. The gaps can be smaller and more uniformly distributed, giving smaller visible grain on magnification, or can be coarser, bigger holes. The black silver crystals however NEVER show up separated, never form individually visible crystals, they are just a lot of them small *******s clumped together, in three dimensions (thus not only one single layer).Many many of these crystals lying ABOVE each other form a thick layer of opaque clumps and make a negative region very dense. This will give the highlights when inverted. If they are forming a less thick layer because received less light and most of them stayed as silver halide and were washed out from the emulsion, the negative will be "thinner" i.e. more transparent. Where there was no light at all, most of them do not reduce to metallic silver, almost all is cleared out and film gets highly transparent.
In the ideal case, the silver crystals are very small and very uniformly distributed in size and position and the layer they form is very uniformly getting optically thicker or thinner, leaving a grain-free look when magnified. However this can only happen when the silver crystals are extremely small and tight packed enough not to leave small gaps between them. Normally there ARE gaps between them which lets light through where it should not let light through. This gives the grain that appears under relatively low magnification and is white i.e. transparent. Projected + magnified on paper, it is black, no matter what the papers' resolution or granular structure is.
Think about it like this: Throw in a jar a bunch of small semitransparent glass balls. If they are very very small, they will fit very tightly and you get a uniform transparency of the "layer" if you look through it from the top. The level of opaqueness will be determined by how thick is the layer and how transparent are the balls. Now, if you increase the ball size, you will get less tight packing of them and eventually, the transparency of the layer will not be uniform, you will see gaps when you look through it. In the case of big big balls, i.e. big silver crystals, which are indeed determined by film type AND development, no matter how opaque the balls are there will always be gaps between them unless you stack a real thick layer, or you cleverly change the balls into something that fit better and leave no gaps, like, the famous t-max or Acros or Delta films have flat silver crystals that fit tighter than traditional 3D-shaped ones.
However you will never be able to discern the individual balls i.e. the individual silver crystals, these will always be clumped together and way too small individually - unless you have only a few in the jar and a really strong magnification, of course.
There is a clear definition of grain, as i said it's not the zebra thing.
Did you actually take a look on the image i posted above? The image is a digitally recorded magnified piece of film (negative) through a microscope, inverted digitally to positive. Has nothing to do with paper image grains.
The grains are black. Obviously, since the image is inverted, the grains in the piece of films were W H I T E.
I mentioned a professional book above. I quote from it:
"It is the gaps that result in grain showing in the print." Page 15. There are even some nice illustrations.
Wikipedia does not contradict what i say. It says, the grains are due to the presence of small grains of a metallic silver ,which is true - EVERYTHING in the imaging process is due to the silver crystals. Wiki does not say, however, that the grain visible in magnifications is these silver crystals, which they are not.
So, that's it, i can't say more obviously; you either believe it or look it up or forget it all and keep thinking that you can see the silver crystals growing in the new years' afternoon light
edit:here it is,further magnified, the nose of the dude (and inverted).
Attachments
Last edited:
Pherdinand
the snow must go on
Oh and, intelligence doesn't have a lot to do with this, it's just relatively simple chemistry and optics. But if in doubt whether i'm just fooling around with you, i do happen to have a Ph.D. in physics (magneto-optics, nanoscience, materials science). Which does not make me a better photographer at all, alas.
Finally, it is not correct to call them "silver molecules". They are simple silver atoms with some inevitable junk around them, precipitated in a sub-micrometer crystalline form.
Svitantti
Well-known
Are you saying it is not metallic silver (grouped together) that I see as black when I am in the darkroom using grain focusing aid? Or scanning film with a film scanner (watching negative image, not inverted)? They are not the grain, but the gaps? Then what is the "white" or transparent area?
I would guess that silver is not transparent, as your magic balls in the example are...
Anyway I think now the thing is, what we mean by the word "grain".
Pherdinand
the snow must go on
When you see black material,it is the thick layer of silver crystals clumped together. When you see white dots, it is light going through the gaps. When you make a positive out of the negative, see my image above, you get GRAIN which is black. This is coming from the gaps between the silver clumps, which is consistent with its color.
This is all i said... don't know how to say it more clearly.
This is all i said... don't know how to say it more clearly.