Tyler, you been working too hard. I was referring to my own thinking being incomplete. I'm going for a certain look that only 8x10 has delivered - so far. I'm just wondering where things get lost. I think I was looking in the wrong place, in fact, I'm sure of it. I should be cured now.Originally Posted by Tyler Boley
Lenny
EigerStudios
Museum Quality Drum Scanning and Printing
Lenny, I'm picking on you. I know what you are after and how difficult it is. I'm merely trying to correct misperceptions indicated in some posts about the curves tool potentially hammering files or compressing levels, not being incremental enough, or in general being part of the problem.
In this pursuit of B&W excellence, it's important to not divert into areas that are NOT the problem and stay on point since the goal is so elusive, hence my earlier remarks about world views vs facts. We all love to hate Adobe, in this case I don't think they are the problem, given careful and proper use.
Tyler
You're right, of course. I find it hard out here to do all this on my own. Like you, I have had to research things one way and the other (by trial and error), to figure out how StudioPrint works, where it does and where it doesn't, along the rest of the software, the paper, the inks. I am sure I have a whole pile of additional suppositions that aren't correct based upon incorrect conclusions I've made during testing.
And yes, I love to hate Adobe as well. Using version 5 at the moment, on my brand new Mac tower wondering where the "themes" are - it looks way too much like a PC app. (Sorry, PC guys, it just isn't my thing.) 5 is a little better, but still a pain in the ars.
Lenny
EigerStudios
Museum Quality Drum Scanning and Printing
My experience is that all things being image quality will always be better with the larger format when comparing film of the same type in 8X10, 4X5 or MF. So if you are comparing the same file in 8X10 and 4X5 it is kind of a no brainer that the 8X10 image is going to look better because of the smooth tones, certainly in any print over 16X20 and perhaps even at that size depending on how close you put your nose to the print. And that would be true even if the resolution of the 4X5 negative it 2X that of the 8X10 negative because even if you have the same amount of detail the structure of the film will be smoother with 8X10 because of less enlargment.
The only way 4X5 can match 8X10 in image quality (or Mamiya 7 can match 4X5) is by the user of a higher resolution film with finer grain. I know for a fact, at least to my own satisfaction, that Mamiya 7 negatives on Fuji Acros, if well exposed and developed, equal or beat print quality from 4X5 Tri-X or TMY-2 negatives. Naturally we are talking about an apples to apples comparison where both cameras are used on a tripod, at a shutter speed that does not cause vibration, and at an optimum aperture.
The characteristics of B&W film are fairly straight forward. There is grain, resolution, dynamic range, curve type and spectral sensitivity. Did I miss something? Image quality itself does not result from any one of these characteristics but from all of them, and how the negatives matches the printing process. I think often people lose their way because they place too much emphasis on just one or two aspects of image quality and lose sight of the whole.
Sandy King
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I'd like to describe something in analogue terms that I think we may miss in these discussions, and as a test of my own thinking.
At various points in the discussion, the notion of a chain has been mentioned, with resolution being determined by the weakest link in the chain. But I don't think a chain is a good analogy. The chain concept suggests that if any link is strong enough, it has the same effect as if it is infinitely strong. If the resolution of, say, the lens is greater than the film, then the lens no longer has any effect on what we see. I don't think that is correct.
The point behind thinking in terms of modulation transfer is to think of waveforms. The scene presents a pattern of waveforms, some of which have, from the perspective of the camera location, infinitely sharp edges, and some of which have gradations.
A lens always renders the scene with gradations--if we look at a small enough piece of the scene that it projects. A lens imparts its own look in the way that it converts the scene's edges and gradations into gradations that do or don't appear to be sharp (even for scenery elements that are in exact focus, which, of course, most aren't). Lines per millimeter is a gross way of measuring this effect, in that it only considers sharp scenery elements. MTF is much better, because it looks at the way the lens modulates the edges and gradations of the scene at different spatial frequencies. But at high enough spatial frequencies, the MTF is always less than 100%--there is a point at which the lens will turn any sharp detail into a smooth gradation.
The film has a completely different way of integrating the information. It imposes its own patterns on the scene, with its own modulation effects. How it does so is what makes each film different, and, from an artistic perspective, this leads to photographers having preferences. Some tonal gradations imposed by the lens may be rendered as a sharp edge again by the film, if it lacks the ability to render a gradation at that spatial resolution. A film may render a straight detail projected by the lens as a ragged edge, where the raggedness of the edge (if it is fine enough) creates the impression of a gradation, and in so doing might add to or obscure the gradation projected by the lens.
If we enlarge, then the enlarger lens and the enlarging paper will each put their characteristic stamp on the result.
It's not a chain. Rather, it's a series of transparent overlays, with each imposing a different way of representing fine detail.
Scanning film also imposes a different pattern on the image. The film's ragged pattern imposed on the gradations projected by the lens will get sliced in a regular grid pattern of samples, and each sample will integrate whatever it sees in that sample. And with many scanners, the samples will overlap, so that each sample will integrate the content of that sample, plus some information from the film in neighboring samples. And scanners that use CCD arrays will scan different colors spatially offset from one another. In that way, the scanner also imposes a modulation by superposing it's sensor frequency and color array on top of the modulation frequencies that are on the film.
So, we have a superposition of wave patterns--the scene, the lens, the film, and the scanner. Each works at a different frequency, and each does different things at different frequencies. Only when one step in the process is grossly less able to handle important frequencies than the others does it become dominant. If one step has much greater resolution than the others, then it has less effect on the integrated total.
In practical terms, if our goal is to render the integrated image as recorded on the film with no further effect, the scanner must be able to see finely enough to describe the grain shapes. So, a film that can resolve x lines/mm might need to be scanned at 10x or 100x to render those grains accurately. Any less will cause the result to see the modulation effects of the scanner, and any less will cause a change in the way gradations are rendered in fine detail.
If our goal is to produce pleasing prints, then we can make use of or work around the modulation effects of the scanner. If that is our goal, then we can determine scanning resolution on the basis of what produces pleasing results for the prints we will make. The rendering of fine detail in a print will be the integrated or superposed modulation of the scene, the lens, the film, and the scanner, with none imposing such an effect as to undermine our aesthetic intent. This is the situation that leads to the chain analogy, but for one of those steps to dominate the result negatively, its modulation has to be a gross effect compared to the fine effects of the other steps. So, again, a scanner might have to have ten times the effect on a given detail than the lens for it to dominate the final result.
A step cannot dominate the result by being too finely resolved. If we modulate accurately at finer levels, the gradations at grosser levels will be accurate. The finer the spatial resolution, the fewer shades of gray are needed to still be accurate at much lower spatial resolutions. There is a spatial resolution where we can provide only binary black or white and still end up with a completely smooth gray scale at lower resolutions. If we get banding at lower levels, it is because our data has been represented at lower resolution, not lower bit depth. But I'm not talking about pixel counts, but rather clusters of pixels all the same color--this is what we call banding or posterization--, which is another way of lowering spatial resolution. Given that we can't practically scan at 100 or 1000 times what we intend on a print in terms of spatial resolution, we end up worrying about accurately integrating larger samples. Our samples are so large that we are forced to represent them as accurate integrations of what they are sampling.
So, for low-res scanners, we want lots of color depth and accurate sampling. The higher the resolution of the scanner, the less accurate each sample needs to be.
I suspect a PMT drum scanner outperforms flatbeds more because of its very high resolution than because of its accuracy for each sample. It may have resolution some large multiple of other steps in the process, but by so doing, improves accuracy without needing each sample to be more accurate.
An Epson flatbed, on the other hand, has low spatial resolution similar to or lower than other steps in the process. Thus, it must represent each sample accurately. But it does not--there is still too much bleeding from one sample to the next, or from one color to the next within the CCD pattern. A Nikon film scanner probably does not have better CCD technology than the Epson, but performs better in terms of broad tonality because of the higher resolution. I know this is weird thinking, but I believe the science supports it.
So, before we can ask about limits, it seems to me we need to set standards for the result we want. If we want everything a given film offers with no influence from scanning, I think we will need extremely high scanning resolution, perhaps one or two orders of magnitude greater than what we expect from the film. The greater the spatial resolution, the less we have to worry about accuracy, it seems to me. The less the spatial resolution, the more we have to worry about accuracy and color depth.
Rick "whose Epson isn't quite accurate enough for enlargements greater than about 4x" Denney
"The chain concept suggests that if any link is strong enough, it has the same effect as if it is infinitely strong. If the resolution of, say, the lens is greater than the film, then the lens no longer has any effect on what we see. I don't think that is correct."
I may be mistaken, but I thought that the chain analogy suggest that a chain is only as strong as its weakest link. If the film can resolve a lot, but the lens is blurry, then what we get is as only as good as the lens. If the film introduces artifacts of its own, then as long as they are smaller than the lens can resolve, they won't be seen, because the lens can't see them.
Someone can whisper at a distance of 1000 meters, but if my ears can't hear it, then from my perspective it doesn't matter whether they whisper prose or poetry - no ?
Someone on the Moon can write a message on a sheet of paper, but if I can't see it with my naked eyes, does it matter what they write ?
- Ken "wondering if this is a case of things going undetected when falling below a critical threshold" Lee
That is what I am arguing against. There is no hard threshold. The effect of the weak link does not mask the effects of the other links unless it is grossly weaker than the others. With a chain, any link that is even marginally stronger than the weakest link might as well be infinitely strong--it won't be the link that breaks. But an image is not a matter of broken or not broken. It is the summation of layers of subtleties, with each layer applying a filter on the underlying layers. The scene represents the base layer, and the lens, film, scanner, sharpening, other processes, and printer are superimposed on top of that layer. One of those filters might be marginally lower in one measure without masking the effects of underlying layers, or it may interact with those effects in ways that produce a third and unexpected effect (moire aliasing is one example of this).
Thus, the assumption that a scanner does all the job it needs to because it is marginally more highly resolved than other elements in the process is too simplistic. It will still impose effects. It may have to have a resolution orders of magnitude greater to impose no effects.
Rick "who runs into this effect when looking at traffic simulation models" Denney
"The effect of the weak link does not mask the effects of the other links unless it is grossly weaker than the others."
Excellent - Thanks for spelling that out.
I believe what you write is true. I think this also explains why the others layers would minimize the impact of the scanner if it happened to be one of the especially strong layers. You see this kind of thing in practice all the time in that most people are not able to see much, if any, difference between two 16X20 prints from the same 4X5 B&W negative, one scanned with an Epson V700, another with a very high end drum scanner. And that is because when we evaluate prints it is a global response, not a response to one or two discreet values. We need to understand this and not obsess too much about one or two single links in the chain.
Sandy King
For discussion and information about carbon transfer please visit the carbon group at groups.io
[url]https://groups.io/g/carbon
I don't know - I mean I think printing in carbon is pretty obsessive. Certainly not so easy to get it just right. As an artist, I am looking for something. Maybe all the links have to function at a high level for it to work. I can tell you that I'm not interested in photographing with a Canon D-whatever. There are plenty that suggest that this is just fine, and why should I fuss over film and lug around this LF camera. Certainly most here would disagree.
Where is the line of its just fine? Of course, the line is where each person places it. I really like the quality that I get when everything works. (Of course, its a lot better when the image is worthwhile as well.)
For me, it can't matter whether everyone can see the difference visually. I think they do see it, they see an artist who's produced something he or she is willing to stand behind. Especially when there's a consistency to a portfolio. It comes across.
Lenny
EigerStudios
Museum Quality Drum Scanning and Printing
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