Digital versus contact print comparison

[chris jordan]

Hi guys (and Calam), I've got a technical question that maybe someone's looked at. I have a new body of work, all shot on 8x10 film, that I want to print quite small in comparison to my earlier huge prints. These new ones will be 11x14 or so, and I want to print them with as much detail and tonal information as possible. I could use my Epson 9800 of course, and at the 2880 setting that would be pretty dang good. But I'm thinking about contact prints that I've seen over the years, and as many purists have pointed out on this forum, there is just something about contact prints that pretty much blows everything else out of the water.

So here's my question: Would it be possible to acheive higher-quality results if I had my scans made into 11x14 internegatives using the highest-quality film recorder out there, and then contact printed those onto Type C paper? I think it would depend on how good the film recorders are (I don't know what dpi they are capable of), and then also on the grain and resolving power of Fuji Crystal Archive paper. Does anyone know how these two factors would compare with inkjet prints made at 2880 dpi?

Any thoughts would be much appreciated, as always.

~cj (Seattle)

www.chrisjordan.com

[paulr]

I don't have any experience with this in color, but my black and white prints (carbon pigment quadtone) made at contact print size acutally look better in most cases than contact prints from the same negative. and by better, i mean that they have a greater sense of those qualities that i normally associate with contact prints (the realness of surface textures, the smoothness of tones, the sharpness of details without any harshness, etc.).

not sure if color printers are good enough to give this same effect, but i'd give it a try before going the more complex/expensive route. I do believe the best film recorders will outdo any printer when it comes to resolution and dynamic range. How that translates into a final print is another story.

[David Luttmann]

Hey Chris,

What finish are you aiming for? Resolution is one thing. But it may be hard to compare a Crystal Archive Matte or Glossy with an inkjet matte finish. If you were printing 8x10, there may be an advantage in tonality with the contact print. The internegative will kill that advantage going to 11x14.

A good scan and output at 2880 on your 9800 (I'm jealous by the way.....still using a 7600) will give superb results to all but those who like to view prints thru a loupe (or electron microscope!).

Maybe you can answer a question for me. I read somewhere that you mount your prints onto plexiglass and apply a coating to the surface of the print. What coating are you using?

Best regards,

[Oren Grad]

Chris, it depends what "quality" means to you.

To my eye, there's no inkjet print that looks like a contact print (on a traditional photo paper that is - alt-process printing on art papers raises other questions). You might like one or the other, but they're just not the same beast, period.

I doubt that a C-print made from an 8x10 negative scanned and written out to an 11x14 internegative with a film recorder would pass muster with a real contact print junkie either - you're adding two intermediate optical stages plus an extra physical image carrier plus some enlargement. There's no way that won't affect the look of the print. It will certainly look qualitatively different from an inkjet, too.

I don't think you can calculate this one on theoretical grounds, based on resolution specifications or anything else. I think you need to have a sample picture printed both ways, and see which you prefer.

[paulr]

"I doubt that a C-print made from an 8x10 negative scanned and written out to an 11x14 internegative with a film recorder would pass muster with a real contact print junkie either - you're adding two intermediate optical stages plus an extra physical image carrier plus some enlargement."

I'm not so sure. Skillfully applied sharpening on a high quality file can be remarkable. I never would have thought a scanned print could look better than a contact print, but now I've seen it, with my own work.

I also don't think surface is going to be an issue if you're planning to face mount to plexi.

[scott_6029]

While I have not done this with 8 x 10, I have made 30x40 color images with 4 x 5 drum-scanned transparencies and the resolution and tonality is exceptional. Personally, I don't think you would need to go the extra internegative route. The detail on the 30x40 from a 4 x 5 is stunning and I am quite particular for detail on enlarged images. Honestly, I can see more 'loss' in detail based on my 'focusing' technique between several enlargements....that's how much detail comes through.

[Eric Jones]

The only experience I have is with the Cymbolic Sciences Lightjet 2080 Film Recorder. You can image out to 11x14 film at a maximum of 1016 dpi. One problem you may run into is coming across 11x14 Color Negative Film without some sort of special order. I'm not up to speed on how dpi translates in lpl/mm but I'm sure an 8x10 Drum Scan @ 2000 dpi imaged onto an 11x14 Negative @ 1016 dpi will far exceed what Fuji Crystal Archive and our own eyes can resolve. And oh, you can also write directly to paper on the Lightjet 2080, so you could write out to Fuji Crystal Archive at 1016 dpi and skip the whole interneg, contact process. That far exceeds what at Lightjet 5000 series printer or a Chromira can do.

[David Luttmann]

Eric,

Good rule of thumb for lp/mm & dpi is 2.4 dpi for one lp. This could be as low as about 2.15 dpi / lp but aliasing could become an issue at that level.

[Oren Grad]

I'm not so sure. Skillfully applied sharpening on a high quality file can be remarkable. I never would have thought a scanned print could look better than a contact print, but now I've seen it, with my own work.

Paul, you've made my point. Depending on what he's hoping to achieve, a scanned negative output to inkjet or internegative for C-print may well look better for Chris's purposes than a contact print would. But it will look different.

I think there are at least two different questions getting mixed up here. The first is, can you make a print that 's indistinguishable from a contact print using these other methods. I think the answer is no. The second question is, which of these alternative methods will be subjectively most pleasing for Chris's purposes. That question I can't answer.

There's also a third question, I guess, although Chris seems to be already assuming an answer to it. That's whether contact prints are somehow better in some absolute sense than other types of print. I don't see much point in debating that one, since that's entirely a matter of personal taste. I happen to really like contact prints (though I like enlargements sometimes, too); others don't really care one way or another, or actively prefer the attributes you can get from an inkjet or other method that involves intermediate processing. Nothing wrong with that - may many different flowers bloom!

[chris jordan]

Hi guys, thanks for all of your interesting input. I realize I left out some details so here they are. My hope is to acheive higher resolution prints than can be gotten from the Epson 9800. The Epson requires interpolation of the image to 360 dpi before printing; then it prints that 360 dpi image out at 2880 (meaning that each pixel is divided into a grid of ink dots). Although many people say that resolution is the limit of what we can see, I have seen many contact prints that just look better-- there is a creamy smoothness that is incredibly beautiful, as if the print had a much finer "dot" pattern than the best digital print.

So what I am hoping to do is take my 1GB scans, Photoshop them to my taste, and then output a new color negative at 14x16" size, at much higher resolution than 360 dpi. I realize it will be enlarged, so it won't be the quality of the original film, but maybe that difference will be minimal. I am wondering if I then contact print that new negative (which would be generated at 1200 dpi or whatever), might that produce that creamy smooth feeling. Maybe it wouldn't be as sharp and perfect as a real contact print, but it might be better than printing the digital file directly at 360 dpi.

Further thoughts?

~cj

[Doug Dolde]

Chris-

Dan Burkholder has a book called "Making Digital Negatives for Contact Printing". Might be worth checking out.

www.danburkholder.com/Pages/main_pages/book_info_main_page1.htm (http://www.danburkholder.com/Pages/main_pages/book_info_main_page1.htm)

[paulr]

"The first is, can you make a print that 's indistinguishable from a contact print using these other methods. I think the answer is no. "

I'd certainly agree with that. I don't think it's often possible to make any one thing indistinguishable from any other thing. But that's not usually the point, unless you have something you've done already and feel compelled to match it ... not the case here.

"The second question is, which of these alternative methods will be subjectively most pleasing for Chris's purposes. That question I can't answer."

Nor can I, but I suspect the first question is, will the easy way give results that are pleasing for his purposes? If so, that removes the need to do it the difficult, epensive way. Both methods are flexible enough to produce such a wide range of results. A lot will come down to the quality of the inkjet printer ... if it has the resolution (and freedom from visible dots) needed to give the right level of quality. I suspect it does, based on what I've seen, but only experimenting will tell.

As far as how much resolution it takes to match the visible detail of a contact print, I find you need less than you might think. The very finest detail I've been able to make out in any of my contact prints, in unusually high contrast areas, has been 7 lp/mm. In areas of more normal contrast it's 5 lp/mm. By far the most important thing is the level of contrast maintained in the 1 to 5 lp/mm range. Resolution beyond that means nothing unless you're looking at the print with a loupe.

for what it's worth, my eyes are proably above average for this kind of thing ... no glasses, and I can read the Condensed Oxford English Dictionary pretty comfortably without the magnifying glass.

7 lp/mm is probably achievable with good fidelity and without aliasing at 400 to 450 pixels per inch ... which is possibly part of why Chris finds contact prints to look better than 360 ppi epson prints (the test would be if prints made with a small format epson using the 720 ppi driver look signinficantly better). It's also possible that trying to create the full gammut of colors and tones with 6 to 8 inks, and whatever stochastic algorhythm is available at 2880 dots per inch, just isn't capable of fooling the eye into seeing perfect smoothness. In the world of black and white, 4 monochrome inks and the same kind of printer seem to be able to do this, but I don't know about color.

[David Luttmann]

Paul,

That echoes my tests with the Lightjet at the 402 dpi setting from film scans. At 402 dpi, approx resolution is just shy of 7 line pairs at normal contrast. It can approach 9 lines pairs on higher contrast targets. Yes, it can measure better if you're photographing air force test charts....but I don't see many charts in photography magazines or galleries.

This is one of those times where the numbers are much lower than many people think. We quite often hear about figures of 30 to 50 line pairs for LF contact prints which is rubbish considering the paper cannot maintain that level of detail nor can the eye discern it without a loupe. More wishful thinking on the part of the printer than anything!

Cheers,

[neil poulsen]

Dan's book doesn't really focus on color. I just took his workshop, and he focuses primarily on black and white, pt/pd, or pt/pd on pigment using a black and white digital negative. The color aspect of his work (pt/pd on pigment) is unique and beautiful, but nothing like the print for which you're aiming.

To me, the look of contact printing comes as much from not using an enlarger as it does from the excellent detail inherent in a contact print, and from the fact that one's using silver based materials. Using an enlarger introduces flair and probably other idiosynchrasies that give a print that non-contact printed look. That's our frame of reference when we view a contact print, how it compares to an enlarged print.

I would want to compare whatever I did with a straight Lightjet or Lambda print from a 1 gigabyte scan. Use the internegative and do the contact print for one print, and then compare. The Lambda or Lightjet also sidesteps the enlarging process and might have a "contact print" look.

If you were targeting a black and white rendering of your films, then Dan's book could be especially appropriate. For example, one could get image setter digital negatives at higher resolution and contact print those.

[sanking]

"As far as how much resolution it takes to match the visible detail of a contact print, I find you need less than you might think. The very finest detail I've been able to make out in any of my contact prints, in unusually high contrast areas, has been 7 lp/mm. In areas of more normal contrast it's 5 lp/mm. By far the most important thing is the level of contrast maintained in the 1 to 5 lp/mm range. Resolution beyond that means nothing unless you're looking at the print with a loupe. "

I don't agree. Studies on the limits of human vision show that at optimumviewing distance of about ten inches the eye is capable of perceiving differences of up to 25 lppm. The eye is not capable of consistently resolving 25 lppm, but it will perceive a difference in sharpness beteen 5 lppm and 25 lppm.

The question should probably be this. What is the worst (in terms of the lowest resolution) image that can be tolerated. In that respect I would agree tht 5-7 lppm is the low limit.

The very best digital prints are limited to a maximum resolution of 7-9 lppm. Contact prints from LF and ULF negatives on suitable papers, AZO for example, are capable of resolution values of 25 lppm and even higher. If you were to compare prints of equal size, one made from a scan of an 8X20 negative and printed on a inkjet printer, the other a direct contact print on AZO, there is no question but that most people would perceive greater sharpness in the AZO print. On the other hand, if one were printing with Pt./Pd. on the art papers we typicaly use with this process, there would likely be no perceived difference in sharpness because the paper itself is the limit to resolution and perceived sharpness.

[sanking]

"This is one of those times where the numbers are much lower than many people think. We quite often hear about figures of 30 to 50 line pairs for LF contact prints which is rubbish considering the paper cannot maintain that level of detail nor can the eye discern it without a loupe. More wishful thinking on the part of the printer than anything! "

Not correct. Ctein tested this and found that some papers are capable of resolution values of up to 125 lppm, which is well beyond the capability of most pictorial films.

[David Luttmann]

Sandy,

I have yet to see any paper capable of those resolutions, unless you spend your days photographing high contrast test charts.....which is not what you'd achieve under standard photographic contrast.

And while the eye may be able to discern the difference between 5 lp and 25 lp....it won't do so at a viewing distance of 18" to 2 feet.....which is about where people woould view a print in the 30" or so size......or are we talking about viewing images at a gallery thru a loupe? I must admit that I don't carry a loupe to look at photos so I can't be much help there.

Truly, if you are achieving 9 line pairs at 11x14 or 16x20, you have a rzor sharp print that needs no apologies.

[Oren Grad]

Sandy - we've had this discussion before. Paulr and Dave don't buy Ctein's results and his interpretation of them. Although I think Ctein's right, I can understand the skepticism - it's actually very difficult to think of an experiment that can be done without exotic equipment that will demonstrate directly, rather than by inference from disparate bits of evidence, not only that contact prints look different from other types, but that information in the 10-30 lp/mm range is specifically what's responsible for the difference.

[sanking]

"And while the eye may be able to discern the difference between 5 lp and 25 lp....it won't do so at a viewing distance of 18" to 2 feet.....which is about where people woould view a print in the 30" or so size......or are we talking about viewing images at a gallery thru a loupe? I must admit that I don't carry a loupe to look at photos so I can't be much help there.

First, I am not talking about looking at prints with a loupe, but at a distance of ten inches, a distance that many people would consider a reasonable distance for critical viewing an 8X10" contact print. At that distance most people will indeed perceive a difference in sharpness between 10 lppm and 30 lppm. And there is absolutely no trouble at all in getting 30 lppm is on a smooth photographic surface from an 8X10 contact print, assuming good technique in focusing and exposing the negative, and further assuming that you don't stop down so much that the lens becomes diffraction limted at less than 30 lppm. That figure, by the way, is about f/64 for a contact print.

Whether or not it is possible to actually get 125 lppm on a print I don't know, and it is probably irrevelant anyway since for all practical purposes that kind of resolution is impossible to get on film. But 30 lppm is a piece of cake.

[paulr]

"I don't agree. Studies on the limits of human vision show that at optimumviewing distance of about ten inches the eye is capable of perceiving differences of up to 25 lppm. The eye is not capable of consistently resolving 25 lppm, but it will perceive a difference in sharpness beteen 5 lppm and 25 lppm."

Can you cite this research? I've looked at a pile of research and it all contradicts this. So does the research that's taken as gospel by the engineers at the lens companies. I've had long conversations about this with tech reps at Schneider.

According to everything I've seen, the maximum theoretical frequency that the eye can discern is about 14 lp/mm (at the 10" focusing distance you describe). This is based purely on the spacing of the rods and cones in the retina, and presumes all other conditions are perfect ... perfect optics of the eye (which no one has), and a high-contrast, backlit slit target whose range of light to dark is measured in the optimum range for human vision.

With actual eyes and their more humble optical abilities, but still with high contrast, backlit test targets, people can discern about 11 lp/mm.

With high contrast detail in actual photographs, the limit tends to be closer to 7 lp/mm.

With medium contrast detail in actual photographs, it's more like 5 lp/mm.

This surprises a lot of people, because these number sound so small. But if you actually measure the size of details on your prints, it will make sense. It's easy to do if you have good scans of the negatives. Look at a contact print, and identify the smallest details that you can see. Then go into photoshop, look at the scan, and measure. A tenth of a milimeter is actually really, really small.

None of this has anything to do with aliasing, or rendering of smooth tones ... just with discerning fine details and textures.

[paulr]

Debating the theoretical maximum resolution of the eye is really just a distraction, though. What counts more is the research done on subjective image quality, which tell us that the 1 to 5 lp/mm frequency range (at ten inches) is what our brains use to discern sharpness and detail. It's the mdulation (contrast level) in this range, rather than the presense of barely perceptible detail in a higher range, that makes a print look sharp or not.

My personal playing around with this suggests that this is a lot of what makes a contact print look like a contact print. An enlargement from a sharp neg with great optics can have impressive modulation at 5 lp/mm, but not nearly as much as a contact print. A look at the MTF charts of the best apo enlarging lenses shows why this is. The lenses are great, but not perfect. They lose several percent modulation even at low frequencies. And if you're making all but the smallest enlargements, you're going to be enalrging detail into that 1-5 lp/mm range that is at much higher frequencies on the negative, and which therefore was imaged at lower modulations.

[bglick]

> It's the mdulation (contrast level) in this range, rather than the presense of barely perceptible detail in a higher range, that makes a print look sharp or not.

paulr, the first time I read this several weeks back, it did not register completly, then when I just re read this line, I am starting to appreciate the value of this contribution. It makes sense, this factor just might be the most signficant issue to perceived sharpness of a print.... superceding the benefits of added resolution in the 10 lp/mm + range.....

now, that being said, I think it would make sense, if one took an image, added contrast and sharpened it digitaly, they printed to either the CSI film recorder at 40 lp/mm using paper, or simply printed a large back lit, then photographed with 8x10 camera using positive paper as the film, this would be a very powerful combination..... assuming the sharpening and contrast improvements overcome the lens loss of the second generation, there is good chance this method may match, or even slightly supercede a contact print. This is why I think many people make 8x10 digital prints that appear sharper than any contact print they have seen.... this is a simple case of the digital manipulation adding more to the image, vs. any of the losses the image experiences getting through to print, regardless of the method. And based on how poweful digital manipulation is, I can see this as being a breakthrough in the contact print arena. Except for purist who are more concerned with the process vs. the final product.

I am curious as to your thoughts on this......