Which flatbed scanners will scan film on the glass?

Discussion in 'Digital Darkroom' started by invisibleflash, Mar 7, 2022.

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  1. My Epson V500 would scan film on the glass just fine, sharp with no film holders and any size up to the lid glass size. The Epson V600 has trouble on the glass. It seems to crop the image into rectangles. But more important, the image is not sharp on the glass and needs to be raised. I'm looking for a good film scanner that will go to 6400 dpi or more with on the glass film capability, hopefully up to 5x7.
     
  2. I've got an old Epson 4870 which purports to scan up to 4800 DPI, but I see no improvement over 2400 or even 1200 DPI. Many users feel that these high resolutions claimed for flatbed scanners are much exaggerated. I've no knowledge of current scanners and their capabilities.
    I don't know why that would be. Is the software in professional mode (if that's what it's called on the V600) where you can manually select the area to scan?

    It seems that the V600 has its focus set slightly above the glass surface, as it might be when the film is in holders which raise it slightly. I did once find that my scanner had a lot more depth of field than I had expected, after using it on some 3D objects. I'm surprised that you haven't encountered Newton's Rings with the film directly on the glass.
     
    Last edited: Mar 7, 2022
  3. Heidelberg Topaz scans on glass but probably won't deliver your ++insane dpi demand.
     
  4. In my experience, with thousands of slides digitized, anything beyond a true 4000 pixels per inch in normal cases resolves 'grain' and dye clouds. There are some special films that may be exceptions, but not even Kodachrome...

    The main limitation is the resolution of the film itself, not just the scanner limitations.

    There may be something new out there now, but until a few years ago the claimed 6400 and above resolutions on flatbeds were sales division fantasies.

    for some older comparisons see
    2015: A scanning Odyssey - Nikon Super Coolscan LS-9000 ED

    but you'll have to skip over the once readable but now opaque direct paste in of images.....
     
    Last edited: Mar 8, 2022
    invisibleflash likes this.
  5. Reading through JDM's article, it's easy to forget how many and varied film scanners were available during the film - digital transition. Where are they now ...?
     
  6. The V850 scans up to 8x10 including 5x7 on the glass but it uses a secondary lens for that. THe primary lens is for scanning film up to 4x5 in film holders above the glass platen. I don;t believe the scans on the glass go that high in dpi. But at 2400, a 5x7 would be equivalent to 40"x56" print at 300dpi.
     
  7. ...or 64"x80" for a 8x10 negative.
     
  8. Any claim of 6400 ppi 'true optical resolution' for a flatbed that scans 5"x7" is going to be pure hype. Because (1) no company now makes a linear CCD scanner sensor that's more than 10,000 photo receptors wide, and (2) the lens needed to get that sort of resolution would be prohibitively expensive. Also (3) it's unlikely the stepper mechanics could be made fine or precise enough to render <4 microns (25.4mm/6400), further divided by the optical magnification, accurately at the sensor.

    So, sorry I. F. but your dream machine just doesn't, and is unlikely to ever exist.

    And +1 to 4000 ppi being about the practical limit of detail to be scraped from any pictorial film - at the plane of perfect focus in the original subject, and with perfect scanner focus and a high-quality copying lens working at f/5.6 or wider.

    That's a lot of parameters to get dead right! Otherwise you'll just end up with an over-abundance of 'empty' pixels.
     
    PapaTango and digitaldog like this.
  9. digitaldog

    digitaldog Andrew Rodney

    The effective resolution of the V850, based on tests here indicates it is 2300 ppi.
    Test report film-flatbed-scanner Epson Perfection V850 Pro transparency unit: experiences report; image quality, scanning slides, medium formats

    The nominal resolution of the Epson Perfection V850 Pro is 6400 ppi. The fact that this value can not nearly be reached has already been proven based on the predecessor model, the V700 Photo, which reached less than 40% of the nominal 6400 ppi.
    The Epson Perfection V850 Pro yields an effective resolution of 2300 ppi if the template is scanned with 4800 ppi. Using the professional scanning software SilverFast Ai Studio, this value is increased to an effective 2600 ppi.
     
  10. I scan negs all the time on my old-ish Epson V750, and Epson 4990, with excellent results. Emulsion side down, flatten curve with a 4x5 sheet of Anti-Newton glass, from my old Bessler enlarger neg holder. Not sure where you can buy the glass, Google is your friend.
     
  11. That is more or less how it is with the V500. Super high dpi offer lower res it seems.
     
  12. It is not insane for negs.

    For paper I scan at 600, 800 and 1200 dpi.
     
  13. Ok, thanks!
     
  14. Maybe not insane... just not economically or practically viable.

    At an RR close to 1:1 the effective f-number of a lens is doubled, and diffraction dictates that a true 6400 ppi resolution (=125 lppmm) needs an effective lens aperture wider than f/5.6. So a diffraction-limited f/2.8 - at infinity - scanning lens would be needed, and that's not going to come cheap. Nor small enough to be incorporated in a practical flatbed scanner for that matter. Especially one covering 5"x7".
     

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