Resolution loss from transparency to print

[january112013]

I use only a 90SW in wilderness landscapes. The transparency is far sharper than any scan and print I have paid for using Heidleberg, Cannon, etc. Will I do better going back to direct "chrome" prints and is that even possible?
Regards
Jim

[vinny]

Yes. No.
It's called SHARPENING. Use it wisely.

[january112013]

Yes. No.

Phooey.
Better to hear than to go on hoping.

[Drew Wiley]

"Sharpening" in Fauxtoshop terminology partially equates to correction, partially to faking something
when a degree of sharpness is in fact lost in the overall process. No digital print can really equal a precise direct enlargement, though one can get close if all your stars align and you are using a laser
printing device rather than inkjet. Cibachrome used to be the sharpness standard, and the only high-end option for direct chrome printing. Now it is almost all gone. So that leaves you either the option of shooting color negs and printing them directly onto RA4 paper, or printing chromes via internegs (which very few labs ever did correctly to begin with), or going the scanning and digital route and finding someone who really knows what they're doing. My own philosophy is, if you want something done right, do it yourself!

[january112013]

Thanks Drew. Funny, when I first tried 4x5 I shot a color neg with each chrome. Somehow got away from it. Think I will go back and see if I am happier. Any recommendations on neg film?
Jim

[paulr]

I will take an opposing view and say that I have never seen a darkroom enlargement that can equal a print made from a good scan, if we are talking about detail and sharpness. Some of my experience comes from working at a custom lab; most of it comes from my own large format black and white work, which was all darkroom based for fifteen years. I then reprinted most of it digitally years later, first for a book project, and then to continue printing after my papers had been discontinued.

My enlarger was a Beseler 45 with a custom lens stage that allowed precise alignment, a glass carrier, and a Schneider Apo Componon HM 150 lens, which according to the MTF curves (and to the people at Salt Hill) was the sharpest lens you could get. I had a cold light head (no fan) and kept the thing laser aligned, and focussed with a critical focuser.

The prints I made at the lab were on a horizontal 8x10 HK enlarger with a glassless carier that pulled the neg flat like a drum skin. It autofocused with a laser onto a vacuum easel. It used Rodenstock's top line lenses.

None of the prints from these setups comes close to prints I can make from scans from a $500 epson 4880 scanner*. I mean, not remotely close. Anyone in NYC please feel free to come in and I can give you a look. I can also show why this is. The MTF response of enlarging lenses, while relatively impressive, still represents a significant loss in contrast at higher image frequencies. I have the curves on all the lenses in question. Light scattering at the paper surface, and defocus due to paper not being 100% flat are probably also minor culprits.

Sharpening algorithms are extremely powerful. This means they give you a lot of power to make things look great or to make things look terrible. Learning a good sharpening workflow takes a fair amount of practice and possibly also some studying ... the kind of dedication I would not expect from someone who deliberately spells the name of the software wrong. I have confidence in the abilities of the technology, if only because I can make 18" wide digital prints that equal the sharpness and sense of tactility that I see in my 4x5 contact prints. Not long ago I would have doubted that this was possible.

Horses for courses when it comes to print materials, but I personally never cared for any color darkroom papers. I find Ciba quite garish and the RA4 papers just looked to me like RC prints with mediocre color. Some of the modern Fuji papers look nice, and actually have some color longevity, but I don't see anything that approaches the look and quality of the best inkjet papers available today. I just think ink has left everything else in the dust. And it's the only technology that is still under active r&d ... it's only going to get better.


*I wet mount 4x5 negs onto float glass and use shims to place the emulsion at the exact focal plane. There is some debate over how much difference, if any, this makes. I haven't compared enough to comment. I jumped through these hoops because it seemed like a good idea.

[Drew Wiley]

Well, sorry to see that you never learned proper enlargment technique, Paul, but it does make a difference! And "sharpening" is not the same thing as reproducing actual sharpness in the original image. It might be essential to making a convincing digital print if used judiciously, but is still not the same thing. Maybe if you ever actually got onto first base with a color darkroom you would understand
what second and third base look like too, instead of going around telling people it can't be done. I'm
happy you've found a suitable niche for your own style, but in terms of objective advice, you're not even on the map when in comes to analog printing technique.

[Corran]

I'm with Paul, assuming we are talking about a direct enlargement with no masks for sharpening compared to a properly scanned and processed (sharpened) negative printed digitally. It's obvious.

Now tonality is a different thing, but if we restrict things to simply detail/resolution I would say digital > enlarging. But I still wet print b&w because of the look/feel of the images over digital printing.

[Drew Wiley]

Time for some of you to get out and start looking at some quality work. I really don't care who is with
who. Masks aren't necessarily for sharpening. It's about hue and tone control. An unsharp mask might
lends an artificial impression to something with less than ideal acutance (I've done that with 120 TMX
negs, for instance, because they have poor edge effect - and that's essentially what you're doing in
the namesake technique in PS) - but really ... it is a different subject. If I want to see serious digital prints, I have friends who have multi-million dollar digital labs. They take me seriously for some strange reason.

[Corran]

I've seen plenty of quality work from both sides of the coin. A large digital print from a 12mp camera certainly falls apart if you are trying to print bigger than it can handle, but if we are talking about say a 16x20 print of a 4x5 negative in the darkroom compared to the same negative scanned well and digitally printed (not ink), the digital is going to be objectively sharper. A contact print seems to be able to be as sharp from what I've seen.

[Drew Wiley]

Corran - with digital, regardless of the quality of the scan itself, you're bottlenecked at the printing step. You either have to shoot it with a battery of tiny Krylon cans (inkjet) or with Chromira, or with
lasers like Lightjet or Lambda. All this kind of technology might be remarkable and still evolving to
some extent, but at this point in time just can't resolve things to the degree a large piece of original
film and apo enlarging lens can. I really don't care what one chooses esthetically. Each of us aspires to
master our own tools. But if you can surpass digital output with respect to the simple variable of
sharpness per se, something is seriously wrong.

[Drew Wiley]

"Can't" (stiff fingers as usual - one more reason to avoid PS in the off hours).

[Corran]

I'm certainly not going to argue that I have a completely fool-proof enlarging setup. But I find it interesting to read Paul's description of clearly a well aligned enlarger with excellent lens - an optimum system if there ever was one - and he sees exactly the same thing I do. I kept trying to chase down "issues" with my technique until I asked a veteran what he thought of my prints in terms of sharpness/detail and he said they look fine - as good as they're going to get. He's exhibited all over the country so I respect his opinion. I have pressed the point of not having a USM for the wet prints - because that very well may get things closer to equal - but with digital USM and a Lightjet print from a good printer, I've gotten sharper results, period.

I'll say it again though - I still prefer the look of a silver print.

[january112013]

It is good to see there really is room for "art" in photography beyond picture composition. The varying (and contrasting) comments show as much. Thank you all.
At the risk of saying something really dumb (or maybe really smart): A transparency (or neg) of the chart that shows line pair separation scale. Then scan the film and print versus a direct (?) RA4 print from film should show if there is a notable difference. Disregarding color. No?

[Drew Wiley]

No., There are a lot of variables, most of which the usual geek-speak suspects seem oblivious to. As
far as I'm concerned, alogorithms refer to woodpeckers attempting to mimic hip-hop. Paul's old optical
setup and workflow sounds pretty primitive to me. That's certainly no criticism of his current output or personal taste. He just prefers different tools than I do. I really don't want to get into too much of a food fight about this, since "sharpness" certainly isn't everything in this game, and I'm clearly butting
heads with people who just don't have enough background to relate. But the notion that extremely high-quality prints cannot currently be made in a traditional darkroom is utter BS.

[Corran]

Paul's old optical setup and workflow sounds pretty primitive to me.

Explain how his setup was primitive and how you could get better detail/sharpness with it please.


I'm clearly butting heads with people who just don't have enough background to relate.

I'll take Paul's experience and reputation over yours right now frankly.


But the notion that extremely high-quality prints cannot currently be made in a traditional darkroom is utter BS.

Now where did anyone say that??

[Drew Wiley]

I'm ducking out of this conversation. If you want to actually learn something fine. Otherwise, don't waste my time. The proof is in the pudding.

[Corran]

The proof is in the pudding.

Now that's something we can agree upon.

I'm listening to what you are saying, I just don't agree, and you've shown no compelling evidence except "I've done this and that so I know better than you."
I'm sorry but that's just not good enough.

The holier-than-thou attitude exhibited by some members of this "community" is just sad.

[Jac@stafford.net]

A strictly academic question.

Presuming a film that can resolve better than 80 lp/mm, then a taking lens of 60 lp/mm and an enlarging lens of 60 lp/mm, what is the resolution at the print surface?

If I can see sharp grain through the focus scope, I'm happy. Just being curious here.

[Drew Wiley]

Yes, that would appear to be a direct question. But it depends on the specific medium. A very smooth
polyester-based medium like film itself or Fuji Supergloss print material (or formerly, Ciba) will accept more detail than conventional fiber-based or RC papers. This is true evern laser-printing. Quite a bit
still has to transact beween that aerial view under the focus magnifier and the medium itself.

[Nathan Potter]

Jac, by a strictly academic answer and with no enlargement at the paper, the chain of lp/mm you cite would result in about 22 lp/mm at the enlarging paper at 1:1. Each doubling of the enlargement halves the lp/mm at the paper.

Of course per the above arguments, all of which I think have a degree of validity, there is a lot more to the comparison than just academics.

For me, how the textural and fine detail of the original scene is preserved through the entire workflow is important in some cases. If the film original contains the desired level of detail then from my experience the best replication is obtained from a high quality optical system. I tend to agree with Drew on this.

OTOH I find a scanning digital workflow utilizing a 2000 nominal spi scan, for example, with judicial sharpening in PS can actually appear to be a sharper print. For some images I prefer this. My problem is that the digitally enhanced sharpness is to some degree artificial in that it does not replicate the fine detail or microcontrast in the original scene (or on film) like a high quality enlarging lens can. This is particularly true using a fairly high contrast enlarger.

I would certainly cite the Ilfochrome work of Chris Burkett for state of the art in optical reproduction but I also work with Ilfochrome and 2000 spi scanning and would generally confirm what I said above.

I'm not sure the difference is at all significant when we consider very high quality drum scanning in comparison to an all optical workflow.

Nate Potter, Austin TX.

[Jac@stafford.net]

Thank you all for the good discussion.

Visual intelligence, or how humans perceive is an academic interest of mine. I had the privilege of working with some excellent psychologists (the perceptual kind, not shrinks) and others in the sciences. One of the things that came up in conversation makes me wonder if having been a photographer and darkroom printer for forty years has changed the way I perceive some things, in particular I do not perceive the Cornsweet illusion. Nor is my vision confused by certain black-and-white tonal differences caused by surrounding and adjacencies. Has anyone else here a similar experience?

Note that I am still entirely susceptible to confusions of colors caused by surrounds and adjacencies. I have normal to excellent color perception, but not as good as the 1% who have the best. (I do very little color photography.)

Aside: A friend of mine is an accomplished, published documentary photographer. He does all 'straight photography' in MF and 6x17cm. At a show I mentioned to him that his prints were soft on the left edge and he responded, "That's the kind of thing only a photographer would notice." I think our discussions are very much along the same line. It is a good thing.

[Drew Wiley]

You can simply bypass a lot of the MTF calculations with a simple analogy. You have a lens on a view
camera (some better than others), then a piece of polyester or acetate film on the back. You expose it.
IF the film was flat, properly focussed etc. you view that on a lightbox under a high-power magnifier
and can often see a LOT of detail. Same principle at the enlarging station. Now look thru a loupe at
an inkjet print or lightjet print or a typical substrate. Not much there. This isn't about how good it looks
to an ordinary viewer (which might be fine) but about the academic ability to hold resolution. All the
number crunching in the world won't change that. You are only as good as your weakest link. A proper
optical system, given a highly detailed oringal neg or transparency, will transfer virtually all that information onto an equivalent polyester photosensitive surface. Paper and ink cannot. Again, none of
this is about esthetics, but simply why splitting hairs over published MTF data is a very minor issue
compared to the other problems in reproduction.

[january112013]

Hey Drew,
That last analysis cleared up my question. Thanks
Now, is there anywhere on the planet where darkroom printing is still done?
Jim

[paulr]

The proof may be in the pudding, Drew, but you haven't offered any. Just personal attlacks. I've invited anyone in the NYC area to come to my studio to look for themselves.

You say my enlarging settup was primitive; I'd love to hear about a more advanced one. But for the sake of argument, I'll agree, and just let people compare my inkjet prints to contact prints from the same negatives. I'll even put 3X enlarged ink prints against contact prints from the same negative.

Ascertaining sharpness by looking through a loupe is just blowing smoke; sharpness is highly size dependent. This wasn't obvious with analog tools, although people sensitive to the process who used staining developers and other techniques that produce edge effects figured this out. Digital tools make it obvious to anyone.

You're incorrect in saying you can't add sharpness. I believe you mean that you can't add detail, which is not at all the same thing. Sharpness is a subjective quality, and it's influenced primarily by MTF at a particular range of spatial frequencies. This can increased or reduced with great control.

I'm offering pudding for proof to anyone curious.

[Drew Wiley]

Paul - edge enhancement can be done all kinds of ways and is not the same thing as preserving detail. This is a bit academic
obviously, because if no one really sees micro-detail in the final print, is a mum subject. I do like it when one can work at the
visible limits however. Place a microfilm target in the glass neg carrier and then a piece of high resolution film on a vac easel
and print that and look at it through a high-power loupe or low power microscope. That starts telling you what optics can really do. Way back in the 1930 they were having contests seeing who could put the most number of complete texts of the
Bible on a microdot, and even back then there were film and lenses that could do about thirty! Of course, full scale tonality
photography is a somewhat different subject. I really don't care how someone chooses to print their own work, and there are
many viable specific media. The only issue I have is folks who go around waving their arms and screaming that newer technology trumps everything simply via its novelty. Then they jump thru a lot of software hoops attempting to imitate what
was done better a century ago using primitive techniques. In your case, you've been implying that digital printing actually
has some kind of edge relative to sharpness - and that would have bordered on nonsense a hundred years ago. Maybe it's
easier for things like squirrely 120 films, but there are all kinds of means of analog printing, which don't have the same
output bottenecks that color digital printing does (per resolution that is). Black and white work can be done a little more
precisely, esp by folks with serious prepress and press gear, but millions of bucks put even into that game won't match a
basic 8x10 contact print done correctly. It's technologically impossible. And don't go thinking we Calif folks who are a bunch
of hicks who don't understand what that means. If I want to see world class inkjet or laser printed work I can do so almost
in walking distance. Some of it gets installed in your city for huge sums. I work with some of these folks supplying them specialty gear and chatting esthetic strategy, and you'd be pretty amazed what they can come up with, as well as with their equipment and facilities.

[Drew Wiley]

Oh but Paul - please keep this in perspective. It's a tech debate, and I in no manner whatsoever am implying I don't like your
work in an esthetic sense, or wouldn't admire your own prints in person. And yes, it is kind to invite me to view it in person,
which I would do if I ever had opportunity.

[Bernice Loui]

Edge enhancement, up sampling or etc in post process does not increase the actual amount of information. If this held true then perpetual motion would be real and current information theory has been proven false. These processes can never equal real amounts of information acquired.

It seems the current norm for computer based printing is something like 300 dpi which translated to a dot size of 0.0033". In order to meet the Nyquist criteria for conveying stored information two points are required which means the actual smallest area possible to convey information would be 2x 0.0033" or 0.0066".

The average thickness of a human hair is 0.004".. which is quite visible to most individuals when places on a sheet of white paper at a distance of 12".

Point being, there is far more to image quality than simple lines per mm, dots per inch or any other highly simplified metric of visual acuity. How and the way we see is far more complex than that.

High resolution or information content alone does not make an expressive image.. it takes far more than just these metrics.


Bernice



Paul - edge enhancement can be done all kinds of ways and is not the same thing as preserving detail. This is a bit academic
obviously, because if no one really sees micro-detail in the final print, is a mum subject. I do like it when one can work at the
visible limits however. Place a microfilm target in the glass neg carrier and then a piece of high resolution film on a vac easel
and print that and look at it through a high-power loupe or low power microscope. That starts telling you what optics can really do. Way back in the 1930 they were having contests seeing who could put the most number of complete texts of the
Bible on a microdot, and even back then there were film and lenses that could do about thirty! Of course, full scale tonality
photography is a somewhat different subject. I really don't care how someone chooses to print their own work, and there are
many viable specific media. The only issue I have is folks who go around waving their arms and screaming that newer technology trumps everything simply via its novelty. Then they jump thru a lot of software hoops attempting to imitate what
was done better a century ago using primitive techniques. In your case, you've been implying that digital printing actually
has some kind of edge relative to sharpness - and that would have bordered on nonsense a hundred years ago. Maybe it's
easier for things like squirrely 120 films, but there are all kinds of means of analog printing, which don't have the same
output bottenecks that color digital printing does (per resolution that is). Black and white work can be done a little more
precisely, esp by folks with serious prepress and press gear, but millions of bucks put even into that game won't match a
basic 8x10 contact print done correctly. It's technologically impossible. And don't go thinking we Calif folks who are a bunch
of hicks who don't understand what that means. If I want to see world class inkjet or laser printed work I can do so almost
in walking distance. Some of it gets installed in your city for huge sums. I work with some of these folks supplying them specialty gear and chatting esthetic strategy, and you'd be pretty amazed what they can come up with, as well as with their equipment and facilities.

[Brian C. Miller]

Any recommendations on neg film?
Jim

I just realized that nobody answered this. Ektar 100 is currently "king" for finest grain. However, you should really use this film with a color meter, and balance the film with appropriate filters when you are exposing it. However, do try Portra. It's an artistic call, and a certain subject or scene might be suited to it better.

As for current darkroom work, there are a large number of B&W commercial printers producing up to 20x24. (I know there was a lab in NYC that printed larger, but they don't appear to be doing that any longer.) For larger work, Bob Carnie on the forum prints larger B&W. I don't know about color, so perhaps someone can chime in about a commercial lab which still prints color with an optical-chemical path.

[paulr]

We all agree that there's more to a print than detail, sharpness, and resolution ... which I am not listing as synonyms, because they are not.

This thread brought up issues of what the eye can see, which is what I'm addressing. I have divided this into two separate questions, because "what the eye can see" and "what makes a print look sharp, detailed and clear" are only distantly related, even though we often conflate them.

When I'm talking about sharpness, which is a major component of perceived image quality, I'm talking about a perceptual quality. Imaging scientists and perceptual psychologists start with perception. Like, if 19 out of 20 test subjects said that print A looked sharper than print B. The technicians then find which measureable qualities correlate with that impression.

Old fashioned metrics like total detail and maximum extinction resolution do not correlate. A print that only resolves 6 lp/mm can appear radically sharper and more detailed than one which resolves 30 lp/mm. The eye can't see all that detail, and the detail that it uses to form its impression of image quality is much lower frequencies: 1 to 5 lp/mm. This is why MTF curves have replaced resolution numbers when discussing optical quality.

The higher resolutions matter if you're looking through a loupe or a microfiche machine. This can be significant for some uses, but not for normal viewing of photographs.

My contact prints contain much, much more recoverable detail than my similar sized ink prints from the same negative. But the ink prints appear more sharp and detailed at normal viewing distances. The fact that they are storing less detail is irrelevant, because that added detail is not visible.

Drew keeps saying that my claims are "impossible," but the results are easily visible to anyone who wants to look. The optical science explaining this is also unequivocal, and is easy to lay your hands on today.

[paulr]

The average thickness of a human hair is 0.004".. which is quite visible to most individuals when places on a sheet of white paper at a distance of 12".

Well, .004" is about 1/10mm ... well within what anyone with good eyes can see at that distance.

But much more importantly, the simple visibility of an object doesn't tell us much. This has nothing to do with the appearance of detail. For example, if we drilled a hole with a diameter of a one thousandth of a milimeter in a thin opaque membrane, and shined a bright light through it in a dark room, you'd be able to see that hole. This doesn't mean you can see detail down to .001mm. To test this we would drill two such holes next to each other ... how far apart do they have to be before you preceive them as two holes rather than one? Here we start getting into the actual limits of the eye's optical system.

And we would find numbers more commensurate with what we've been talking about earlier.


Point being, there is far more to image quality than simple lines per mm, dots per inch or any other highly simplified metric of visual acuity. How and the way we see is far more complex than that.

Yes, this has been my point as well. Although I've been demonstrating that you don't need finer resolution to create that sense of sharpness and detail. You need higher contrast of that detail within specific, modestly high ranges of spatial frequency.

[Bernice Loui]

Most viewers do not perceived the increased resolution initially which is why the majority of print viewers may not perceive or value the increased information/resolution in a print. This can change as the viewer is educated and exposed to high definition / high information content images.

I"m not convinced that the current standards of 6-10 LPM at 10"-12" viewing distance is a broad enough metric to measure perceived print quality for some.

I'm not going to take sides on this, I'm willing to put forth some current scientific understanding of how this stuff works.

What I do know and has yet to be convinced is the current digital print output is equal to traditional photographic film/chemical processes as they are inherently different which will produce inherently different results. I need to view more digital process images before I'll form a opinion on what they really are.


Bernice

[Drew Wiley]

And when I'm saying something "can't" be done, I'm obviously referring to this point in time technologically, within some means affordable to serious photographers. On an industrial scale laser-etching can be done truly micro, but you need
an appropriate flawless synthetic receiver medium, and that ain't paper! And you need some way to work a monochrome ink
in. Regarding inkjet, you're restricted by how small you can make the pigments. Two weeks ago I had a conversation with
someone linked to the nano-pigment industry, and process colors still don't exist. Maybe you could do something fun, but it
wouldn't look very real. But if suitable nano pigments ever do arrive on the scene, inkjet as we know it will go extinct.

[Drew Wiley]

Per contact prints, Paul ... it's just as easy to register the same unsharp masking media to a contact print as to an enlargement if one wants edge enhancement in this manner. All kinds of things can be done using traditional graphics skills
or modernized tweaks. I don't contact print very often myself (sometimes), but I do frequently make very high quality 8x10 contact dupes and internegs where a degree of edge enhancement, along with hue and tonality correction, is incorporated into the printing master. Some of this I have a long track record with, like chromes to Ciba, and some, like new Ektar applications, I'm still experimenting with.

[paulr]

I"m not convinced that the current standards of 6-10 LPM at 10"-12" viewing distance is a broad enough metric to measure perceived print quality for some.

Well, it's admirable to not be convinced of such a thing based on some internet discussion. The important thing is have a sense of the relevant questions.

The good news is that if you're really curious about this, it's not terribly difficult to conduct your own tests. Or at least, the tools and expertise needed aren't so hard to find these days.

I think the simplest thing is to find a negative that you have made a very sharp, detailed looking darkroom print from. Then get a good scan of it, and experiment with printing it. I'd suggest limiting the resolution to 300ppi, which would give you a maximum extinction resolution of 6 lp/mm. Set your sharpening radius to 0.1mm (1.2 pixels) and make a few prints with different degrees of sharpening applied.

This will be fairly primitive ... it won't give you state of the art results ... but you'll get an idea of how subjectively sharp and detailed a "low resolution" print can look side by side with its darkroom counterpart. And you'll know that this is on the lower end of what's possible.

[Bernice Loui]

From the previous post, 300 dpi = 0.0033" dot.

From a theoretical point of view, this is the standard for inkjet prints and there are limits to what dot size an inkjet can produce.. it is limited by the ink pigment and print head. This puts a pretty hard wall limit on this printing technology.

In comparison, traditional film and chemical process has random silver or dye particles that are smaller than 0.0033" which allows higher amounts of information/resolution in the results. If the debate is over what is visible or not visible, that is not the debate, it is about what is possible or not possible due to the limitations of each technology..

At this moment in digital print technology, I'm not yet convinced it is mature in the same way film technology is. There is a long ways for digital technology to go.
When digital print technology can produce random sized dots on the order of 0.000001" to 0.000005" then we are nearing what is film is capable of. The orderly nature of digital image sensors and print technology adds to the problem of information reproduction. It is why Moiré patterns happen in digital and not with film.


Bernice



Bernice



And when I'm saying something "can't" be done, I'm obviously referring to this point in time technologically, within some means affordable to serious photographers. On an industrial scale laser-etching can be done truly micro, but you need
an appropriate flawless synthetic receiver medium, and that ain't paper! And you need some way to work a monochrome ink
in. Regarding inkjet, you're restricted by how small you can make the pigments. Two weeks ago I had a conversation with
someone linked to the nano-pigment industry, and process colors still don't exist. Maybe you could do something fun, but it
wouldn't look very real. But if suitable nano pigments ever do arrive on the scene, inkjet as we know it will go extinct.

[paulr]

Drew, pigment size is 100% irrelevant to the print quality. It's probably relevant to printer reliability and resistance to clogging (the biggest thorn in the sides of this medium) but you cannot see pigment particles without a microscope. Even the size of the ink dots is barely relevant anymore. Dots were invisible to the naked eye long before they got down to their current 3.5 picoliters, or whatever they are. The only reason anyone's messing with dot size anymore is that it effects the screening algorithms, which are constantly being tweaked. Althought the differences from one printer generation to the next these days is so subtle as to be visible only in some instances.

I'm aware that you can make sharpening masks for contact prints and enlargements. The OP offered conventional contact prints as "the holy grail," so this is what I was responding to.

I would be very interested in doing some comparisons with prints made this way. My interest would be entirely academic—I don't see a reason to jump through so many techical hoops using last centuries graphic arts technology. If I wanted to print on traditional hand-coated materials today, I would contact print from digitally made negatives using Jon Cone's process, because I've seen those results and know how good they are and how precise the control is.

[Drew Wiley]

Paul - imagine truly transparent, virtually UV-permanent tricolor pigments as small as organic dyes, just CMY (maybe K too).
No uneveness in the blacks, no need for glycol to keep goop from drying out. Will it ever happen. I don't know. But they're
trying. But for non-inkjet applications like tricolor carbon, there already is a class of pigments which will do that. But I just
don't have the time or energy to fiddle with yet another process. And yes, this is the golden age of hybrid techniques. Pigment size is quite important because the priority is to develop something which will get through smaller and smaller jets,
and hence achieve "true photographic quality" (marketing terms). But if you pull up some of the ink patents involved, you'll
see that at the moment, a lot of these inks are not equal in permancence, and many are simply lakes which might or might
not be superior to the primary dyes in terms of permanence. The bigger problem is, as I just mentioned, the uneveness of
the surface. Ctein was complaining about this to me the other day, as he is now permanently shifting from dye transfer to
inkjet (for both a change of scenery and due to supplies running out). With monochrome the options are a little better. And
things keep improving. And this is all academic - what really counts is how well one masters their chosen media.

[paulr]

From the previous post, 300 dpi = 0.0033" dot.

Notice I said "ppi" not "dpi" a pixel is an image pixel. Each one is made from many, many ink dots. Current printers can lay down 56 to 113 ink dots per linear millimeter. The dots themselves are microscopic. They use less than 5 picoliters of ink (BILIONTHs of a mililiter).


From a theoretical point of view, this is the standard for inkjet prints and there are limits to what dot size an inkjet can produce.. it is limited by the ink pigment and print head. This puts a pretty hard wall limit on this printing technology.

Well, not really. The limitation on image resolution is made by the print driver. Epson drivers can operate at 360ppi or 720ppi. 360 is effectively so high that people can rarely tell the difference if they're not printing on the smoothest paper, and even then the differences usually don't show up unless you're printing type or high contrast graphics.

If you are doing monochrome printing, like with Jon Cone's piezography inks, you use a rip that takes full control over the print heads. That system linearizes seven shades of monochrome inks and can give you the full benefit of 720ppi on smooth papers. The dots are invisible even with a loupe.

I'm not sure I understand why you're talking about what's "theoretically possible." My prints are for looking at. For looking at by humans whose eyes and visual cortexes work reliably similarly. I don't print for microscope operators; I print for people who look at art and who will not get closer than 10cm, because that's as close as a little kid's eyes can focus. Grownups are lucky if they can focus at 20cm.

The reason I can make sharper prints digitally is because of the control the process gives me over sharpness at the relevant spatial frequencies. The presence of detail at irrelevant frequencies is ... irrelevant.


At this moment in digital print technology, I'm not yet convinced it is mature in the same way film technology is. There is a long ways for digital technology to go.

If I agreed I wouldn't have sold my darkroom!


.... then we are nearing what is film is capable of...

Well, now you're talking about the capture medium. That's a whole other conversation and can of worms. I've been talking about printing, and for the purposes of this discussion, we were all talking about printing from film.

[paulr]

Drew, those inks you mention would interest me because they'd probably be less prone to clogging. They're not going to make prints that look sharper or more detailed. Printers have been past the point where improvements make this kind of visible difference for nearly a decade.

[bob carnie]

I am lucky enough to see on a daily basis , prints made by inkjet, prints made by lambda laser, and yes optical prints. I scan and print each day , moving from one process to another , somedays printing all three.

After about 8 years of observing digital process images that has indeed gone into Museums, and Gallery's from our equipment I will say that all the forms of printmaking have their strong points and some weaknesses. I have yet to see a print made from either traditional enlarger or high end digital blow the other away.
In fact the differences are so subtle that even after 35 years of image making and being able to print sniff , I have a hard time saying one process is better than the other. I do look at the images supplied and make an educated guess as to what process will make the image work best. Then I do the tests to see if I was right.


Good negative exposure, good processing, good enlarging practices with good optics and flat film plane will give very sharp results.
Good image capture, good PS editing, good laser equipment with excellent sharpening skills will give very sharp results.

Paper surfaces have the most to do with percieved sharpness, a heavy rag paper will not seem as sharp as a high gloss cibachrome no matter if you print optically or digitally. I was lucky enough to bridge both methods of making cibas and can say that its the workflow that is important...

If you are lucky to live in a large market like Paul does and have the inclination to take advantage of the numerous shows on a weekly basis you will see that his argument is correct.
If you are making complicated contrast, colour masks for enlarger printing you will see Drews point.

I have been lucky enough to live in a large market (Toronto) and see a lot of work from various regions of the world , so I see Paul's point, and as well I do come from Drew's background of complicated mask-making to enhance colour images and can appreciate his viewpoint.

I think it boils down to good workflow , appreciating different print processes and understanding that some will have attributes others do not. I do not think we have ever seen a better time to be making photographs. This mixture of methods is mind boggling and to state one method is better than the other is IMO silly.

We just upgraded today our Cannon IPF 9000 to a Cannon IPF 9400 , a noticeable difference with improved ink sets is apparent .
This is a three year cycle that all users of inkjet will notice until the ink sets match Pro Photos gamut or beyond.
I see a different colour pallet with RA4 than that of our current ink sets, I appreciate both differences and based on the image and how I want to make the final print look, is more important to me than the type of optics or lasers produce the image. The image controls the process as I like both processes sometimes I have to try both to decide, just like I like a glossy print for some of my BW work and Matte surface for others.

[Drew Wiley]

They aren't inks, Paul - they're micro pigments originally designed for totally different applications, so would still need R&D for printing machine application, unless you were simply dispersing them into an assembly printing process analogous to
quad carbon or Fresson. The point is, it would be a vasty simplified system, and you would have true transparency comparable to organic dyes, yet with extreme permanence. Don't hold your breath. Maybe something could be done that resembles early color movie hues or an old Autochrome. But true process colors don't exist yet. In a second category they do, but would not be suitable to inkjet at this time, only layered assembly techniques.

[Drew Wiley]

Just one point, Bob, some of the very most expensive digital printing shown in NYC or even being put into permanent installations in NYC, Germany, or Seoul is being done right in this immediate neighborhood, basically by hired guns with
incredible equipment and backgrounds. Very little of that kind of thing is locally exhibited, though I might try to scheme up
something in the future, nor is it locally sold - we're talking about seven figure stuff. Rich guys around here tend to buy silly pop art and and ocassional AA or EW print. Rich geeks don't generally become good collectors. And the most expensive lenses in the world are made right here; and there are plenty of digital printing gurus around who I know one a first name basis. So cutting-ege techie exposure is no issue at all. Personally, I prefer the look of a platinum print made in a chicken
house by Julia Cameron. By I am currently in the school of hard knocks making the transition from Ciba to Fuji Supergloss both from internegs and current color neg originals - that is, in terms of optimizing this kind of thing to the level of quality
I previous expected with Ciba. A new challenge, but you know ... a step at a time.

[Nathan Potter]

From the previous post, 300 dpi = 0.0033" dot.

At this moment in digital print technology, I'm not yet convinced it is mature in the same way film technology is. There is a long ways for digital technology to go.
When digital print technology can produce random sized dots on the order of 0.000001" to 0.000005" then we are nearing what is film is capable of. The orderly nature of digital image sensors and print technology adds to the problem of information reproduction. It is why Moiré patterns happen in digital and not with film.


Bernice



Bernice

Bernice, your dimensions of 0.000001 to 0.000005 inch for equivalent film resolving power is much too small if you speak of equivalent grain size to dot size. Modern films after development have a typical grain size from 0.5 µm to maybe 10 µm for large clumps. Your figure implies size 0.025 µm to 0.125 µm. (20,000 lp/mm to say 5000 lp/mm). Even the finest emulsions made by Eastman Kodak (Kodak High Resolution Glass Plates) could resolve about 2000 lp/mm. under extraordinarily precise exposure and processing conditions.

By the way I just saw an advertisement by Epson of a new printer with a dot size capability of 25 µm on paper (very smooth paper I assume). Thats 20 lp/mm, 1016 dots/inch. Seems almost overkill for what the human unaided eye can perceive at close viewing distance.
If the print is an enlargement from an original diminutive source then the source film needs to have greater than 20 lp/mm or the information conveyed is emply of the detail that would be possible.

Nate Potter, Austin TX.

[paulr]

By the way I just saw an advertisement by Epson of a new printer with a dot size capability of 25 µm on paper (very smooth paper I assume). Thats 20 lp/mm, 1016 dots/inch. Seems almost overkill for what the human unaided eye can perceive at close viewing distance.

The reason for the tiny dots in a screened printing process is to have as many dots per pixel as possible. The greater the number of dots you can fit in, multiplied by the number of shades of ink, corresponds with the number of discreet dynamic levels you can display. With a high ratio of dots to pixels and a high number of ink shades, it becomes very easy to linearize an inkset and produce tones that are perfectly smooth from paper white to full black. The lower these numbers, the trickier it becomes to get smooth results.

I asked Jon Cone why he upgraded the Piezography inks to six and seven shades of gray ... I thought the older 4 ink process looked amazing. He said it was mostly to make linearization easier. With four inks, it was extremely hard to get the curves and ICC profiles to work. Any deviation and the whole thing would fall apart. This fit my experience—I had had Cone make me a custom ICC profile for the old quadtone inks, and it took him three tries to get it right. The first two weren't even close. Now with the 6 and 7 ink systems, a generic profile works for most people. It's become easy for him to linearize the tones.

[Drew Wiley]

I'd be extremely skeptical that any kind of paper per se could hold micro-detail. Sound like advertising hype to me. You'd need polyester film at a minimum. Just because you might be able to spit it out that fine doesn't mean that's how it will
actually land. And I don't think any of us know what film actually can do. My brother was always of the persuasion that the
"military" was always twenty or thirty years ahead of the curve compared films available to the public. Having seen a number
of classified prints over the years, I'd say that was completely true. Whether it's still true during this era of increasing digital
survelliance, I cannot say either. Ultimately, for me at least, it's not about hypothetical resolution once you're below the
threshold of visual recognition, but about the smoothness of the tones, distribution of the hues (gamut), surface quality of
the print, etc. And in color work at least, inkjet and chemical photography just look different. With monochrome, it's more about toning versus whatever ... personal choices.

[Brian C. Miller]

By the way I just saw an advertisement by Epson of a new printer with a dot size capability of 25 µm on paper (very smooth paper I assume). Thats 20 lp/mm, 1016 dots/inch. Seems almost overkill for what the human unaided eye can perceive at close viewing distance.
If the print is an enlargement from an original diminutive source then the source film needs to have greater than 20 lp/mm or the information conveyed is emply of the detail that would be possible.

Nate Potter, Austin TX.

I took a look at the Epson site, and came across the 7900CTP, which is used for printing aluminum printing press plates. The printer specs claim 150lpi (plate, not paper). That could be the next new frontier, but I'd hate to try and send plates through the mail.

[paulr]

Yup, personal choices. I haven't said my digital prints are better than my darkroom prints. In some cases I think they are and in others not. Someone else looking over my shoulder might have completely contrary opinions. But I think everyone would agree that they appear sharper and more detailed. These are qualities that may or may not be important to any given work.

Film resolution is easy to know. The manufacturers have been publishing MTF curves for a long time. Of course it's a curve, not a hard limit, so it has to be interpreted on situational basis. Papers certainly hold as much detail as film. I've never seen anyone publish MTF data for papers, because they're all probably at 100% all the way up to the point where the detail is too fine to see. The exception would be highly textured art papers. No one reaches for those if they want to see a lot of detail.

[Drew Wiley]

Or course, detail is only one parameter. That's where polyester media like Ciba and Supergloss excel. I also fool around a little bit with dye transfer, which is certainly no winner in that category, but is in terms of gamut and saturation. A few folks are tinkering with the idea of running those dyes thru printers onto mordanted paper, but still some issues, and probably wouldn't compete with inkjet for permanence. But let's face it - something like eight to eleven inks in a set, whereas dyes can do it better gamut-wise in three. Probably an iris printer would work for something like that. But I like the tactility of actual darkroom work. I'm more interested in some of these various options conceptually, cause I only have time to work with
a very limited number of processes for real. Got my gear and methodology, so no sense to change now.

[Nathan Potter]

Paul I hadn't contemplated possible advantages of a 20 µm dot size for halftone dots but inkjet prints are not halftones so I assume you are only comparing the advantages of very fine halftone to what might be a similar advantage with inkjet.

But I've been thinking about the inkjet method of generating large format negatives for direct contact printing, a technique being more widely used for carbon and Pt/Pd contacts and employed by a number of workers here and other places. With 20 µm dot technology a significantly finer digital master could be generated on a transparency film such as pictorico. Such detail on film could even stand a 4X enlargement to paper and still yield around 300 DPI for acceptable print quality.

I tend to agree with Drew that such a tiny dot pattern may be almost nonsensical on most normal papers.

I see the 18 µm line machine is listed as a plotter by Epson so now I'm not so sure it would be suitable for full photographic images although a full color photographic image is shown.
The Epson SureColor T3000 is a 24 inch wide machine at $2995. 36 inch at 3995 and 44 inch at 4495. Advertised in the IEEE Spectrum from the Institute of Electrical and Electronic Engineers. They may be targeting the IC industry where, in particular, I have always been a bit frustrated with the quality from printed blowbacks of chip designs. Cartridges up to 700 ml are listed as available.

Nate Potter, Austin TX.

[paulr]

Paul I hadn't contemplated possible advantages of a 20 µm dot size for halftone dots but inkjet prints are not halftones so I assume you are only comparing the advantages of very fine halftone to what might be a similar advantage with inkjet.

The relationship between dots and pixels is the same. Halftone is ordered and uses amplitude modulation; stochastic is (pseudo)random and uses frequency modulation. But both can create a greater number of smooth tones if they can use finer ink dots relative to the pixel size.


But I've been thinking about the inkjet method of generating large format negatives for direct contact printing, a technique being more widely used for carbon and Pt/Pd contacts and employed by a number of workers here and other places. With 20 µm dot technology a significantly finer digital master could be generated on a transparency film such as pictorico. Such detail on film could even stand a 4X enlargement to paper and still yield around 300 DPI for acceptable print quality.

I've seen this done and it looks great.

I'm not familiar with the line of Epson printers you're talking about.

[Jac@stafford.net]

What of the issue of 'dot gain'? Not relevant today?

Tia

[paulr]

What of the issue of 'dot gain'? Not relevant today?

Tia

You don't have to think about it. It's mimimal, because of the coatings on the paper, and any effect it has on densities gets compensated for in the paper/ink icc profile.

[Bernice Loui]

Ooops off by one decimal point.

Still, I'm not convinced that LPM or DPI is a good overall metric to measure image quality or how we may perceive images. The visual process is far more complex than LPM, MTF, DPI or...

It looks like digital printing continues to advance and improve. At some point, the digital technology will be extremely good. There is market demand for this kind of development at this time.

The real question is where will this all ended up, what will the mature digital imaging technology look like?

Film had a long time to mature into very fine image creation technology which is the results of many, many years of development by both technical folks and artist.
Just think of the billions upon billions of images made on film over it's history.

For now, I'm going to stick to them old ways that works for me.. for now.


Bernice



Bernice, your dimensions of 0.000001 to 0.000005 inch for equivalent film resolving power is much too small if you speak of equivalent grain size to dot size. Modern films after development have a typical grain size from 0.5 µm to maybe 10 µm for large clumps. Your figure implies size 0.025 µm to 0.125 µm. (20,000 lp/mm to say 5000 lp/mm). Even the finest emulsions made by Eastman Kodak (Kodak High Resolution Glass Plates) could resolve about 2000 lp/mm. under extraordinarily precise exposure and processing conditions.

By the way I just saw an advertisement by Epson of a new printer with a dot size capability of 25 µm on paper (very smooth paper I assume). Thats 20 lp/mm, 1016 dots/inch. Seems almost overkill for what the human unaided eye can perceive at close viewing distance.
If the print is an enlargement from an original diminutive source then the source film needs to have greater than 20 lp/mm or the information conveyed is emply of the detail that would be possible.

Nate Potter, Austin TX.

[Jac@stafford.net]

The average thickness of a human hair is 0.004".. which is quite visible
to most individuals when places on a sheet of white paper at a distance of 12".

A trivial aside: the human vision system (eye, but especially brain) can distinguish a human hair but it cannot resolve a dot of the same thickness. We 'see' it through the brain, so-to-speak. This is what makes some subjects susceptible to seeming sharp, while others are not.