Coolscan 5000 sees scratches that DSLR scan doesn't on b/w?

Discussion in 'Digital Darkroom' started by feucht, Feb 7, 2021.

  1. Hello!

    I'm trying to lock in a scanning workflow for B/W 35mm and I've had such a love/hate relationship with my Coolscan 5000 and Vuescan. The detail extracted is second to none, but I'm seeing EVERY flaw as well. There are hairline surface scratches that explode on the screen from these scans that are nowhere to be found on a mirrorless camera scan or a darkroom print.

    Is this just inherent to the scanning physics? Is it scanning the surface and therefore every film base scratch is seen? Again, if you backlight the negative, all of these tiny scratches are invisible. Hence why they don't show up in camera scans or darkroom prints.

    Any ideas?
     
  2. I'd guess it has to do with the difference in light source. The LEDs used in the Nikon scanner are closer to a point-source than the diffuser that's needed for camera copying.

    Does your enlarger have a diffused source as well?
     
    Ed_Ingold likes this.
  3. Yes - The enlarger does. This seems to be the answer. Perhaps I need to ditch the Nikon and embrace camera-scanning.
     
  4. By all means. Scratches serve an important documentary purpose.
     
  5. One idea, old darkroom trick - nose grease. Rub your clean finger along the outside of your nose where nose and cheek meet to pick up a little skin oil, then GENTLY rub it on the negative over the scratch. Usually the scratch disappears.

    Yes, the scratches are inherent to high resolution scanning; you want high resolution, you get everything - warts, scratches, and all. Unfortunately, with most black and white films, you cannot use Digital Ice to remove them.
     
  6. Some people use fluid mounting to eliminate scratches. The fluid has an index of refraction (nearly) equal to that of the film substrate, which masks scratches perfectly. I hadn't thought of it before, but nose grease may be the main ingredient ;)
     
    Last edited: Feb 22, 2021
  7. I have noticed the same thing when scanning silver-based b&w negatives. My Nikon CoolScan V-ED emphasizes negative defects such as tiny scratches and embedded dust that won't brush or blow off. As Rodeo Joe says, the film scanner probably illuminates the negative using a highly colimated or point-source LED array. Local contrast is also higher. These are the same effects we get with a condenser enlarger.

    By contrast, my DSLR dupes using a macro lens and Nikon ES-2 film holder minimize the negative defects, and local contrast is slightly lower. These are the hallmarks of a diffusion enlarger -- which makes sense, because the ES-2 works by diffuse backlight (either ambient or flash). If a negative needs more local contrast, I can add it using the Unsharp Mask filter in Photoshop.

    I use the CoolScan for color negatives and dirty slides, because the infrared dust-removal saves much time in post-processing.

    Not all film scanners are like the Nikon scanners. Years ago I borrowed a Minolta film scanner for a while. It must have had a diffusion light source, because those scans were cleaner than the Nikon scans and less contrasty. Yet they were plenty sharp (grain sharp).
     
  8. It's (some) Nikon scanners that are out-of-step with the rest of the world, by using LEDs.

    Most CCD scanners use(d) a small fluorescent tube for illumination. This is naturally a more diffuse source than an LED.
     
    bgelfand likes this.
  9. Another possible explanation is that direct to camera copying is not resolving as much detail, and is simply blurring out the scratches.
     
    Dave Luttmann and bgelfand like this.
  10. Yeah, right.
    Whatever.
     
  11. There is a lot of truth there. Detail is indeed lost with Bayer interpolation. I find that it takes a much higher rez DSLR scan to equal a lower rez standard scanner. That is based upon my testing anyway.
     
  12. Wow. Mr Luttmann has done his own testing!?

    And not just lifted someone else's 'evidence' off the web?

    But can't be bothered to post the results here.

    My use of dedicated film scanners against digital copying says otherwise.
    Scan-Copy_comparison2.jpg
    All of them resolve the individual dye clouds. So how much more resolution is needed? Because there's certainly no more subject detail to scrape off a bit of film.
     
  13. Some people just can't play nice.

    Cromwell’s Rule
    More than a little ironically, Oliver Cromwell himself wrote to the General Assembly of the Church of Scotland on 3 August 1650 :

    .

    if the shoe fits, wear it.
     
    Dave Luttmann likes this.
  14. I seek not to contradict, but being contradicted, I simply place evidence in front of anyone that cares to see it.

    In my view it's fairly conclusive, together with my actual experience of the experiment.

    And if I am mistaken; show me evidence of the mistake.

    Words alone, with no supporting evidence, are just a pathetic emptiness.

    I feel no sympathy for Mr Luttmann, who in the past has posted images he has no ownership of as being his own work, and in support of assertions later proven to be untrue. That's not 'playing nice' either.
     

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