Film vs. Scanning resolution

Helge said:

and let me just unequivocally state that 2600 dpi does not even begin to out-resolve the potential resolution of those films.

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Not scanning at 2600dpi, but scanning to obtain 2600dpi effective, the V700 delivers around 2000 if scanning 2400.

The potential resolution of the film (400H) is total contrast extintion at 125 lines/mm (let's assume they say line pairs when saying lines) with 1000:1 contrast, but you won't get that detail projected with that contrast. To begin with, an exceptional lens like the Nikon 58mm f/1.4G has a contrast loss of 50% at only 30cycles/mm (https://imaging.nikon.com/lineup/lens/f-mount/singlefocal/normal/af-s_nikkor58mmf_14g/), you may imagine what contrast remains by 80cy/mm.

In pictorial photography you never are able to reach the situation in what the film delivers the maximum capability, simply because projecting on film 1000:1 contrast at 125 cycles/mm is out of reach by far.

Then film has an additional contrast loss at high cy/mm, see datasheet, the contrast the lens is able to conserve is destroyed by the film itself in that situation, and beyond the contrast loss, at high cy/mm pictorial image quality is destroyed by film granularity, an enlargement will show the flaw.

The side by side I pointed shows a well shot real scene, in those conditions a top notch scanner resolving elements from Group 7 of the USAF 1951 glass slide cannot show a benefit over the V700 that cannot even reach Group 6. This is the reality.

Yes, a contrasty silhouette will deliver more defined edges, but a good sharpening job will regenerate prefectly that contour to the point the higher effective resolving power won't be noticed much.

Lachlan Young said:

There's no need for speculation: he was publicly asked to desist in posting those claims by the person whose scans he is distorting the results of.

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No distortion, just a direct reference. This is a totally honest and proficiently made side by side and results are totally clear.

Not only there is no need for speculation, also there is no need for interpretations:

Just under the image: "What is most interesting is that in real life, DPI resolving power may not be adding a whole lot if the image itself doesn't have the resolution to begin with. It will be nice to see how slides look side by side and I expect to see bigger differences there."
https://www.largeformatphotography....rum-Scanners&p=1479176&viewfull=1#post1479176

Yes... this is painful for those having had commercial interests in the scanning and they were forging tests to misslead about the Epson. One day I'll show you my collection of detected forged tests. Good Pros never did that, because their value is in the image crafting, they never had the need to forge tests.

Only second rate operators need to attack the competition with lies.

I should say, that based on the data Fuji provided, I presumed that 125 lp/mm was absolutely perfect conditions for lighting, subject, exposure, etc., and that it would be an unlikely occurrence in the real world.

While doing Yet More Research, I ran across some articles on testing of various LF and MF lenses, it would appear, that with a few exceptions, the best you can expect from LF or MF lenses, is in the range of 60-80 lp/mm.

I would also rather this didn't devolve into the name-calling and ranting that affected a discussion on the LF forum, which is why I specifically avoided any references to any particular scanning technology or manufacturer.

138S said:

Just under the image: "What is most interesting is that in real life, DPI resolving power may not be adding a whole lot if the image itself doesn't have the resolution to begin with. It will be nice to see how slides look side by side and I expect to see bigger differences there."
https://www.largeformatphotography....rum-Scanners&p=1479176&viewfull=1#post1479176

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Goes without saying that "real world" tests are not intended for resolution testing as there are many factors not accounted for. However, given the jump to conclusions perhaps it needs to be said . . .
Portra 160 is not intended for resolution - great latitude but not resolution.
If you want/need resolution then there are far better films for this.
From my own limited testing of Kodak Ektar 100, it is just about a match to my Coolscan's 4000dpi which is clearly far and above the Epsons.
Kodak TMAX100 and any other slide film far outresolves my Coolscan's 4000dpi.

BTW, it is great to reference external sources but unfortunately the originators are not here to represent. OTOH, I have done many repeatable tests so it would be beneficial if participants can represent their own and have it available for peer review.

grat said:

I should say, that based on the data Fuji provided, I presumed that 125 lp/mm was absolutely perfect conditions for lighting, subject, exposure, etc., and that it would be an unlikely occurrence in the real world.

While doing Yet More Research, I ran across some articles on testing of various LF and MF lenses, it would appear, that with a few exceptions, the best you can expect from LF or MF lenses, is in the range of 60-80 lp/mm.

I would also rather this didn't devolve into the name-calling and ranting that affected a discussion on the LF forum, which is why I specifically avoided any references to any particular scanning technology or manufacturer.

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amen to that. I’d rather get on with my life than quibble over minutiae that in many cases isn’t realistically attainable. Suffice it to say that most film is still higher resolution than most total system resolution setups, so the best practice is to determine your required output resolution and scan high enough to meet that. What that number ends up being is what it is, and there’s nothing wrong with that if it works for you.

grat said:

I should say, that based on the data Fuji provided, I presumed that 125 lp/mm was absolutely perfect conditions for lighting, subject, exposure, etc., and that it would be an unlikely occurrence in the real world.

While doing Yet More Research, I ran across some articles on testing of various LF and MF lenses, it would appear, that with a few exceptions, the best you can expect from LF or MF lenses, is in the range of 60-80 lp/mm.

I would also rather this didn't devolve into the name-calling and ranting that affected a discussion on the LF forum, which is why I specifically avoided any references to any particular scanning technology or manufacturer.

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I'd generally agree with Adrian, but would add a small addendum, you will find that it's not necessarily the resolution of the taking lens, nor the notional resolution of the film that matters in the scanning stage - but rather the ability of the scanner or digitisation device to adequately resolve the character of the film (a very different thing from a high contrast resolution test) in a convincing manner - some cheap scanners have real problems with Rodinal because of this - in a way that neither darkroom printing nor high end scanners have. I think this lack of qualitative contextual knowledge is what leads people to accept the often rather poor results from certain scan systems as being an absolute 'truth' too readily.

Lachlan Young said:

I'd generally agree with Adrian, but would add a small addendum, you will find that it's not necessarily the resolution of the taking lens, nor the notional resolution of the film that matters in the scanning stage - but rather the ability of the scanner or digitisation device to adequately resolve the character of the film (a very different thing from a high contrast resolution test) in a convincing manner - some cheap scanners have real problems with Rodinal because of this - in a way that neither darkroom printing nor high end scanners have. I think this lack of qualitative contextual knowledge is what leads people to accept the often rather poor results from certain scan systems as being an absolute 'truth' too readily.

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true. I don’t mean to trivialize the whole resolution thing. It is important, and I go to great lengths in my own setup to get as much as I realistically can, but at some point you need to be able to actually productively scan in volume, and often times, our output needs are low enough that the scanning resolution just isn’t as big of a factor, hence the desire to just get on with it.

My testing led me to a minimum of 11.000 dpi for camera scans if you truly want to resolve the film. But do you need to? Probably not. I don't have any info on drum scans.

You are not resolving grain at 4000 dpi. It looks sort of like grain, but it isn't. And that is for high speed films that are grainy like Tri-X.

For color film and camera scans the Bayer pattern makes mud out of color unless you have a pixel shift camera (I'd assume). That is something to consider.

If you know what you are doing, a darkroom print is still the best resolution you are going to get with current methods, unless you want to do stitching of camera scans. Perhaps the newest Sony with pixel shift can do better but I don't have one to try it.

I'd post examples but I don't want to be a lightning rod for every yahoo out there.....

Les Sarile said:

my Coolscan's 4000dpi which is clearly far and above the Epsons.

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No doubt, another thing is if this makes a practical difference or not, and in what situations...

Also it depends on if you are able to make an optimal Epson scan, V700 and V750 holders did not ensure flatness and height was not adjustable. A 2.5mm fall of the film height provocates a 50% performance loss in the Epson. But with then new ANR glass holders or with the old BetterScanning holders you ensure flatness and adjust height, shortening the difference to the coolscan and many times outresolving what is in the film.

IMO a well made V700 scan always get all what Portra and Ektar records in pictorial situations. Not everybody is able to make a good scan with the Epson... In that side by side the author adjusted well focus, this was an important factor.

Les Sarile said:

Portra 160 is not intended for resolution - great latitude but not resolution. From my own limited testing of Kodak Ektar 100...

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Kodak datasheets, Portra is at left, at high contrast we have the same:



At low contrast we should see if Ektar is superior, I doubt it, anyway at low contrast Ektar performance won't be much to challenge the Epson capability.

Both Ektar and Portra were re-engineered to deliver optimal scans in industrial processors and in digital minilabs, it is debatable if color clouds were made larger or not to overlap avoiding increased color noise from discretization (this happened decades ago) but IMO both are pretty equal because both were equally tunned to perform excellent in the same ultra fast scanning systems.

Les Sarile said:

Kodak TMAX100 and any other slide film far outresolves my Coolscan's 4000dpi.

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TMax 100 has total contrast extintion by 63 lp/mm if projected micro-contrast is low, in that situation even the Epson is able to record most of the IQ.

At 1000:1 TMX resolves 200lp/mm, but 400 lines in a mm (200 white and 200 black) with 10 stops differences can only be obtained with a Lab contact copy, never you'll find that in pictorial situations. Some lab practical TMX tests shooting flat targets show 90 lp/mm with the microscope at extintion... to get that we would require a 8000dpi drum scan.

But not many real shots get that performace, you have to shot on tripod, at sweet aperture, with all in focus. A distant mountain can be all in perfect focus, but atmospheric conditions have to be ideal, and common scenes having near subjects are in the DOF and not in perfect focus...

Even TMAX can record 100lp/mm in pictorial situations not many shots will have that IQ, to begin with many of us usually shot handheld most of the times.

Les Sarile said:

BTW, it is great to reference external sources but unfortunately the originators are not here to represent. OTOH, I have done many repeatable tests so it would be beneficial if participants can represent their own and have it available for peer review.

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Look, that thread has 162 posts, all was said, if you have any doubt you may read those 162 post, (some of them are of high conceptual quality). IMO all is clarified, no interpretation needed. The author clearly belives that drums are superior, and of course they are. Still a surprise was there when inspecting practical results.

Patrick Robert James said:

My testing led me to a minimum of 11.000 dpi for camera scans if you truly want to resolve the film. But do you need to? Probably not.

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exactly. It’s fun get into the numbers, but, at the end of the day, unless you’re making really huge prints that are going to be inspected from a few inches away with a magnifying glass, we don’t actually need to go there. Have you seen a reasonable scan displayed on a 60 inch 4K TV? It tends to look pretty good, even at lower scan resolutions. It’s pretty easy to get caught up in the whole resolution thing and lose sight of the fact that ~8MP displayed at 60 inches on the diagonal at a reasonable viewing distance looks quite good.

138S said:

Look, that thread has 162 posts, all was said, if you have any doubt you may read those 162 post, (some of them are of high conceptual quality). IMO all is clarified, no interpretation needed. The author clearly belives that drums are superior, and of course they are. Still a surprise was there when inspecting practical results.

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There's no denying a lot was stated and posted. I can agree with the USAF target test but even then the OP discovered that depending on filters used, cleaning the target or replacing a stepper motor, results can change. I didn't really pay that much more attention as I didn't participate in it. The "real world" test example is completely arbitrary and only applies to that specific example. Could very well be the lowest bar set but really who knows for sure.

So basically, we all already know where the Epson flatbeds - and others, achieve in terms of real details achieved but now we just want to see what an individual can "settle" for. In that case it is clearly an individual decision based on some personal needs.

Like I said, personal representation and let's subject it to peer review and see if it holds water.

Adrian Bacon said:

the bit rate of music is a totally different thing as it’s usually compressed. Uncompressed CD sound is ~1.5Mbps. If it’s a compressed mp3, if you want reasonably good sound, 160Kbps is pretty much the minimum for most things though 128 is passable, if it’s AAC compressed, 128 is the minimum, with 96 as passable. Both are lossy, so it will depend on the content.

for recording video, here in the US, broadcast TV mastering minimum is MPEG 2 video at 30 frames per second with 4:2:2 color sampling and 50Mbps. ATSC digital TV over the air is ~19Mbps MPEG 2. Most cable TV is that at best.

MP4 (with h.264 compression) is approximately twice as efficient as MPEG 2 compression, so ~24Mbps for a minimum is fine, though many cameras encode at much higher bit rates than that. This is all for full HD 1080 video. If shooting 4K, multiply by 4 for that minimum, and by 4 again for 8K.

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I just checked what my Sony RX100M4 camera records. In 4K movie mode, sound is 48kHz. stereo (2). Bitrate is 1537kbps. Video is 29.97 frames,3820x2160 resolution, data rate 94303kpbs, Total bit rate 95829kbps. Sony uses their own XAVC-S format. I think it's wrapped in H.264 or MP4, whatever that means.

I guess my question is about the 48kHz sound at a bitrate of 1537kbps. What does that mean and is it good?

Adrian Bacon said:

exactly. It’s fun get into the numbers, but, at the end of the day, unless you’re making really huge prints that are going to be inspected from a few inches away with a magnifying glass, we don’t actually need to go there. Have you seen a reasonable scan displayed on a 60 inch 4K TV? It tends to look pretty good, even at lower scan resolutions. It’s pretty easy to get caught up in the whole resolution thing and lose sight of the fact that ~8MP displayed at 60 inches on the diagonal at a reasonable viewing distance looks quite good.

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Well it matters for a number of reasons (other than giant prints).
INPO:
Projections: Slide allows you to “print” almost as large as you want.

Cropping: Sometimes you just want to do it.

And sometimes you just have to counter the idiot who tells you films general maximum equivalent resolution is about 6 - 10 megapixels.
As much as you try to hold yourself too good for it.
Reputation and specmanship matters for the future of film. Sorry, but it does.
Once we have them over on our side we can teach them all the nuances.
But if a person hears they have to pay up to several dollars, for something they are used to be getting for absolutely free and don’t think much of, and even “in worse resolution”, many will just stop being interested instantly, or can be FUD induced to not take the leap.

Helge said:

And sometimes you just have to counter the idiot who tells you films general maximum equivalent resolution is about 6 - 10 megapixels.
As much as you try to hold yourself too good for it.
Reputation and specmanship matters for the future of film. Sorry, but it does.

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Wow, are we up to 6 - 10 MP now . . .

Imagine my surprise when in early 2000 with the release of the 3MP Canon D30 that a pro photog said it outresolves 35mm Fuji Provia scanned with an Imacon scanner . . . https://luminous-landscape.com/d30-vs-film/

See, this is the problem with "real world" testing even by seemingly competent people with supposedly good equipment.

138S said:

Kodak datasheets, Portra is at left, at high contrast we have the same:

View attachment 253140

At low contrast we should see if Ektar is superior, I doubt it, anyway at low contrast Ektar performance won't be much to challenge the Epson capability.

Both Ektar and Portra were re-engineered to deliver optimal scans in industrial processors and in digital minilabs, it is debatable if color clouds were made larger or not to overlap avoiding increased color noise from discretization (this happened decades ago) but IMO both are pretty equal because both were equally tunned to perform excellent in the same ultra fast scanning systems.

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Again these are cycles. Not lines. And negative film was always meant as an intermediary, with contrast meant to be raised in print.
PE wrote that the only things done to optimize for scanning was having less “tooth” on the non emulsion side of the film. The rest is the same. Scanning and wet printing (and projection) has the same basic optical requirements.
There is no magic you can do to the emulsion to make it easier to scan, that wouldn’t also benefit darkroom print and slide projection.

Adrian Bacon said:

true. I don’t mean to trivialize the whole resolution thing. It is important, and I go to great lengths in my own setup to get as much as I realistically can, but at some point you need to be able to actually productively scan in volume, and often times, our output needs are low enough that the scanning resolution just isn’t as big of a factor, hence the desire to just get on with it.

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Oh, absolutely - and that's where you'd think that some company or other would have been smart enough by now to understand that MTF matters more than outright pixels & offer a decently fast & sharp scanner at a fair price based off extant technology...

Helge said:

Again these are cycles. Not lines. And negative film was always meant as an intermediary, with contrast meant to be raised in print.
PE wrote that the only things done to optimize for scanning was having less “tooth” on the non emulsion side of the film. The rest is the same. Scanning and wet printing (and projection) has the same basic optical requirements.
There is no magic you can do to the emulsion to make it easier to scan, that wouldn’t also benefit darkroom print and slide projection.

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138S has been making the same factually inaccurate claims for years. You could literally play troll bingo with them. Finer, sharper, more tightly packed dye clouds = better scans and better darkroom prints.

Alan Edward Klein said:

I just checked what my Sony RX100M4 camera records. In 4K movie mode, sound is 48kHz. stereo (2). Bitrate is 1537kbps. Video is 29.97 frames,3820x2160 resolution, data rate 94303kpbs, Total bit rate 95829kbps. Sony uses their own XAVC-S format. I think it's wrapped in H.264 or MP4, whatever that means.

I guess my question is about the 48kHz sound at a bitrate of 1537kbps. What does that mean and is it good?

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the sound is good. ~1500Kbps is uncompressed 16 bit sound.

Les Sarile said:

So basically, we all already know where the Epson flatbeds - and others, achieve in terms of real details achieved

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Many people having an Epson V700 don't know what that machine is able, because not having adjusted media height or ensured flatness, or not knowing how to make the refined sharpening Epson scans require in post, to obtain the best result while totally avoiding overshot.

Les Sarile said:

In that case it is clearly an individual decision based on some personal needs.

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Les, see the table at the bottom, and you'll see that that test is not that arbitrary, but a good example of the reality.

Helge said:

There is no magic you can do to the emulsion to make it easier to scan, that wouldn’t also benefit darkroom print and slide projection.

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Since many years ago RA-4 darkroom printing has been declared near extinct, almost nobody prints RA-4 optically. Priority has been scanning since the digital minilab era in the 1990s. What % of the RA-4 prints are optic? one in one million?

If you observe color negatives of the pre digital minilab era with a microscope, at (say) x400 you may see that the image structure (color clouds) changed compared to color negative film made in the digital minilab era.

See this table:



Reference: http://www.tmax100.com/photo/pdf/film.pdf

These are results from contact copies. Amazingly the 40 years old VR100 (The kodak product that introduced T-Grain in around 1980) has the best rating of the color films, but it had some grain and more color noise in the scanning. If you make clouds larger then clouds from a color layer overlap better with clouds in the other layers, lowering color noise in the discretization.

There always had been a trade between size of color clouds vs granularity, a film that scans easy may require larger color clouds, at the end lost sharpness can be compensated with a wise digital sharpening. Of course a detailed analysis should consider what average cloud size we have for each density in each layer, measured in the reticle of a microscope... but to compare it's enough to inspect at x400 how gray subjects with same density (concrete buildings, for example) have the clouds overlaping less or more.


In the other hand that contact test suggests a resolution value in ppi, this is 3300 to 3700 for the old Portra variants, but those are tests from contact copies, those figures have to be lowered for practical shooting conditions, the same document calculates the actual ppi once the lens performance has degradated the image, note that Portra 160 was peaking 2450 with a very good 140 lp/mm lens:



This fully explains why an Epson V700 is able to get all IQ Portra 160 is able to record, as it is able to resolve 2900dpi effective in the Hor axis and 2300 in the vertical one.

I guess this table is a precise answer to what OP was asking.

138S said:

I guess this table is a precise answer to what OP was asking.

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Well, it's certainly informative. The article around it, however, is fascinating, and really does answer many questions, including questions raised by comments in this particular thread. It suffers from being 14 years old, but other than the newer emulsions not being listed, it even covers the technology in drum scanners and the Epson v750 and friends (Nuts.... wasn't going to mention hardware).

Most interesting to me is the distinction between B&W and color-- which I knew was an issue in digital, but hadn't occurred to me it was also an issue in film. I'm wondering what would happen if, for a color negative, you did one scan in B&W at very high resolution, and another in color at a more modest resolution and integrated the two images in a similar manner to how frequency separation works for sharpening-- use the black and white for detail, and the color scan for, well, color.

I won't say I have my answer-- but I have a much better grasp on which questions to ask.

138S said:

Les, see the table at the bottom, and you'll see that that test is not that arbitrary, but a good example of the reality.

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I said the "real world" test was in the outside thread you referenced was completely arbitrary, not independently verifiable and has no standards for testing to conform to or a target to achieve.

Seemingly you post some nice references so how about the some of your own test results to show your point indisputably? Make it available for peer review.

138S said:

Reference: http://www.tmax100.com/photo/pdf/film.pdf

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BTW, I just skimmed through this and will study it in more depth as it looks interesting to me.

grat said:

I'm wondering what would happen if, for a color negative, you did one scan in B&W at very high resolution, and another in color at a more modest resolution and integrated the two images in a similar manner to how frequency separation works for sharpening-- use the black and white for detail, and the color scan for, well, color.

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no real need. This is already done in many image formats. The luminance information is stored in full resolution and the chroma information is stored in less resolution. This is where you see the 4:4:4, 4:2:2, and 4:2:0 video encoding. Btw, JPEG is the same. It’s 4:2:2 encoding. Full luminance resolution, half color resolution. Tiff files can be the encoded the same way, just almost nobody does it that way if doing tiff files as bayer encoding gives greater color fidelity for similar file size, and full RGB is best for maximum quality.

So as a semi-tangent to this article, let's say you want to scan 120 film? Is an Epson V800/850 going to give better results than a V700/750? I'm not trolling, but I need to "prepare" my "Chief Financial Officer" for a "purchase approval" for a scanner in the near future.

PhilBurton said:

So as a semi-tangent to this article, let's say you want to scan 120 film? Is an Epson V800/850 going to give better results than a V700/750? I'm not trolling, but I need to "prepare" my "Chief Financial Officer" for a "purchase approval" for a scanner in the near future.

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You can review the comparison at https://www.filmscanner.info/en/EpsonPerfectionV800Photo.html
Effectively, the V800 is equal to the V850 and achieves slightly higher res then the V700. The V800 has better holders and faster scan times too.

Les Sarile said:

BTW, I just skimmed through this and will study it in more depth as it looks interesting to me.

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I’ve read through that several times over the years. Quite a lot of interesting stuff.