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Thread: Digital printing 6x9 vs 4x5

  1. #1

    Digital printing 6x9 vs 4x5

    N.B. This is not really a question, but an answer to a year old thread.

    Based on a discussion about quality difference in digital printing from 5x7in vs 6x7cm (see Digital threads) I decided, being a scientist, that I should run an experiment. The impetus was conflicting statements about whether there were disc ernable differences between rollfilm and 4x5 when printing to a Lightjet5000 at sizes up to 20x24 (4000x5000 pixels). Bill Nordstrom has said that there would b e no significant visible difference. Joe Holmes said that a 4000x5000 scan from 4x5 would be absolutely sharper than the same resolution scan from 6x7 (or 6x9). Since I have great faith in both of these individuals, I decided I had to run a test.

    So, I shot the same scene in 4x5 and 6x9. Both cameras used Velvia, and I select ed a lens for the 4x5 that was 50% longer than for the roll film. The lenses wer e a 180 Apo-Symmar for 4x5 and a 120 Apo-Symmar for rollfilm. The 4x5 was expose d at f/22, the 6x9 at f/16 to compensate for both differing diffraction limits a nd depths of field. The 4x5 was scanned at 1400 dpi, the 6x9 at 2100 dpi. Assumi ng (as everyone seems to say) that the optimum input to the Lightjet is 203 dpi, those resolutions correspond to a print with a maximum dimension of about 30 in ches.

    I have compared the resulting scans in Photoshop. They are incredibly similar. T here are no specific details in the scan from 4x5 that are not visible in the sc an from 6x9. However, the edge contrast is slightly better in the scan from 4x5 giving the impression of just a hair sharper image. The difference is very subtl e but it does exist. I doubt that it would be as noticible in a print as on a mo nitor.

    I conclude that Bill and Joe are both right. The 4x5 does generate a slightly "s harper" scan, but a moderate size print, say up to 20x30, from 6x9 will be virtu ally indistinguishable from one made from the larger sheet film.

    I would love comments or feedback, and am willing to email snippets of the scans to anyone that wants to see what the difference in format means in this digital age.

  2. #2

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    Digital printing 6x9 vs 4x5

    Glenn,

    thank you for your experiment, however, I cannot see that it proves a thing. you are bandwidth limited, in a sense, constrained by your fixed size and printer resolution. you've stacked the cards against 4x5 by sampling much lower. might as well have scanned an 8x10 at even less of a sample rate. if my math doesn't fail me, you'd see the same in 35mm scanned at 5760dpi. the geometries of the scanning hardware should favour better conrast/tone in the larger prints, but I would think it would be marginal in this testcase.

    if you were to reverse the process, and reduce the image size, would you be surprised to see little difference in the three, 1" images?

  3. #3

    Digital printing 6x9 vs 4x5

    Daniel:

    I don't disagree with your statements, but I was not trying to prove that 6x9 is equal to 4x5 in any sense, only that the additional information on the 4x5 is not manifested in the specific size prints I was investigating. No question that I was limiting the 4x5 with the sampling at 1400 dpi. But that is the "real world" limitation with the Lightjet at these print sizes. On the other hand, the results suggest that with real world lenses and film backs, 2100 dpi is approaching the limit of usable information from roll film (its approaching 50 lp/mm). The 20x24 or 24x30 size is simply the trade- off point of these limitations. For those of us that never print larger than 20x24 inch prints, the combination of high-res drum scanning and the Lightjet have effectively removed the gap in final print quality between roll-film sizes and 4x5.

  4. #4

    Join Date
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    Digital printing 6x9 vs 4x5

    Have you actually compared enlarged prints? I think this would provide the real answer. Keep in mind that a monitor can only display a resolution of 72 dpi (some 90 dpi) I just feel that viewing these in Photoshop is not the right place to compare. Thanks.

  5. #5

    Digital printing 6x9 vs 4x5

    Glenn, I shoot only 6 x 9 cm color transparencies ( I bought my Horseman VH from you and love it). Although I suspect there is virtually no difference between high quality digital prints up to 20" x 30" (drum scanned and printed on a Lightjet 5000) from 6 x 9 cm or 4" x 5" slides, I have a couple of methodological problems with your test. First, the maxmium resolution from the Lightjet is at 120 dots per cm, about 300 dpi. Although Bill Nordstrom prints everything at 80 dots per cm, many other people (including Bill Atkinson and Nancy Scans) claim you can see a slightly improved quality when printing at 120 dots per cm. Especially for your test this would be sginificant as the Lightjet increases the resolution from res 8 to res 12 when the lower res files are provided. Second, who did the scanning? What kind of a scanner was used? I would hope a Tango Drum scanner or equivalent. Did the scan oeprator sharpen in the scan at all? This may account for some difference. Moreover, if you didn't sharpen at all in the scan stage, this would not be a very practical real world test because everyone sharpens scans before printing them to the Lightjet. A more useful test would be to sharpen each print at the scan stage and in Photoshop to the point where you would want to for that given print; you could then comopare (a) differences in sharpness, and (b) differences in tonal subtlety (i.e. the 6 x 9 scan which may be sharpened a tad more . . . but maybe not because the shorter focal length gives better depth of field . . . may give up tonal subtlety for the Photoshop enhanced sharpness). . . A gratuitous plug -- when you get a chance check out my new site at www.naturelandscape.com. It displays my

  6. #6

    Digital printing 6x9 vs 4x5

    Glenn, you started your experiment with a flawed method. If you want to capture all the information the LightJet can output, you need to scan to get a 300MB file. If you want to make a valid comparison of the formats, you should scan each file at a resolution that will yield 300MB files. After downsampling the files to the desired output size, you will see a bit more sharpness and more detail from the larger original.

    Two of my friends own a business specializing in scanning slides and preparing them for LightJet output. Their clients include some of the best landscape photographers in the world. I rented time on their Tango drum scanner a few weeks ago and we discussed this very issue while we were working. After doing this for the past six months since he got the Tango, Rich has seen what different formats are capable of producing. His opinion, based on examining the final output, is that larger formats do give better prints, even though they are scanned to the same file size as medium format.

    My 6x7 slides required a bot more than 4100 pixels per inch to capture 300MB data. If we assume 4x5 film has the same resolution as 120 film, and the lenses have the same resolving power, the larger area will yield more details (think of veins in a leaf). When you prepare the file in PhotoShop and apply a sharpening filter the greater detail will result in a sharper print.

    And as someone already pointed out, monitors are low resolution devices. The correct way to definitively test this is to scan both slides to 300MB and output them at 120 pixels/cm (304.8 dpi) which is the LightJet's highest quality output.

    All that being said, the differences among various original sizes are much more subtle using digital methods than when using traditional methods. Right now we're limited by the LightJet's output size restriction, if you want to think of 50 inches by 50 inches as a restriction.

    I ordered a 4x5 camera last weekend. In a few months I'll go back and scan some 4x5 slides. I might just try this experiment myself and see what happens. I could slap a 6x9 back on the 4x5 and use my 135 and 210 Rodenstock lenses for the comparison. Which leads to another flaw in this experiment. Medium format lenses have more resolving power than large format lenses. Sigh. Does nayone have a Hassleblad or Rollei I can borrow for a few months? Current models preferred.

  7. #7

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    Digital printing 6x9 vs 4x5

    take a balloon, blow it up to a reasonable size, and with a felt-pin marker, draw a 6x9cm rectangle. mark several horizontal lines, representing a scan line across the rectangle. now, blow the balloon up till the rectangle becomes approximately 4x5" and that is what you have done. same image, bigger, less scan lines per inch, but identical to what you started with. nothing has changed.

    you are constrained at one end by your printer, and the resolution of your scan hardware and film structure on the other. obviously the 4x5 will allow for bigger prints, and the increase in scan data would allow average and smoother tonality when scaled downward.

    project your argument in the other direction, and you would speculate that APS would scan as well. scanned high enough, you could easily present the amount of data the printed required, though image data would be equaled by noise and grain acquisition.

    give me oversampled 4x5. tonality to die for.

  8. #8

    Digital printing 6x9 vs 4x5

    Daniel, I like the balloon analogy, but for digital work we need to modify it a bit.

    Blow up a large balloon. Draw two identical size rectangles on each. In one box draw lines at a fixed distance apart to represent the total film resolution of a 6x9 slide. Now draw more lines lines in the 4x5 box (this is a thought experiment, the actual number does not matter).

    You now have two boxes of equal size, but one contains more lines than the other. These boxes represent the 300MB scans off a Tango drum scanner, which can be printed at 40x50 inches on a LightJet 5000. The lines represent the details in the original slides. Now let some air out of the balloon until the boxes are the right size for 24x30 prints. The 4x5 box still contains more lines, even though they are both the same size.

    This is where you get more detail in your LightJet prints, and the subtle sharpness difference. Sharpness is really not an issue with digital prints, as we are not enlarging anything as we do in a traditional darkroom print. The difference will be in detail resolution and grain size. The sharpness difference we can see is a result of the sharpening filter having more edges to work on.

    To take this a bit further, a 35mm color slide scanned at 5,000 dpi yields a 100MB file. Scan a large format negative to 100MB and print it at 16x20. There will be less grain in the print, more detail, and a bit better sharpness. The grain and detail differences will be quite evident. The sharpness difference will be very subtle.

  9. #9

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    Digital printing 6x9 vs 4x5

    Darron,

    you hold the answers, that is if I read your postings correctly. you just Tango scanned your images, and you have a UMAX flatbed scanner. I realize you did this for archival purposes, but if we are all saying the same thing, your ink jet 8x10 prints (you select the size) should look much the same, whether you print from your Tango or UMAX. now that, would be an interesting observation. dismissing dynamic range, and other scan issues, tell us how the prints differ, if at all.

  10. #10

    Digital printing 6x9 vs 4x5

    As soon as I got home and opened the Tango scans in Photoshop I sold my Umax PowerLook III. The 8x10 inkjet prints from the Umax scanned files and from the Tango scans are silimar in sharpness, but the tonality and dynamic range from the Tango scans are incredible. The noise floor (borrowing an audio term for lack of a better description) is much better on the Tango scans too.

    After seeing the Tango scans I just couldn't see bothering with a flatbed scanner again. The JPEG files I uploaded to my web site do not do the Tango scans justice. I have some 16x16 LightJet prints in transit to my house. These were printed from files scanned from a 6x6 slide taken with a Mamiya C330f and 135 lens. They are marvelous on screen.

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