Scanning with Imacon 949 and printing with lightjet 430

Discussion in 'Digital Darkroom' started by tony_black|1, Jul 24, 2006.

  1. I asked a similar question couple days ago but still couldnt find what I am
    looking for exactly.

    Here is the deal,

    I have 35mm and 645 film to be scanned with Imacon 949 and will be printed
    about 30"x40" or a little bit bigger by lightjet 430 for an exhibition.

    1-I couldnt scan my 35mm negative more then 20"x30" at 300dpi or my 645
    negative around same size which comes to 100mb for 645 and 150mb for 35mm.

    2-Which scanner I need to scan these negatives to get 30"x40"at 300dpi so that
    i dont have to resize or interpolate the images? I need the max quality.

    or am i doing something wrong when i am scanning with 949?

    thanks very much.
     
  2. At a scan resolution of 4000spi and an output dpi of 300, a little 35mm piece of film only gives you a file around 13x19 inches or so. There generally isn't a whole lot more information in the negative, so to do bigger than this you need to interpolate. 30x40 is extreme for 35mm film, but with enough viewing distance it could be okay.

    Why the 645 is giving you a smaller file than the 35mm is baffling. Maybe someone else can help.
     
  3. Imacon has higher resolution for 35mm than medium format - hence the file size
    discrepancy. 100Mb is correct for a max resolution 8 bit scan from 645 negative.

    A drum scanner will give you more resolution from your 645 neg. So will desktop scanners
    from Minolta and Nikon. Even an Epson flatbed will give you higher resolution.

    But none of these options (with possible exception of the drum scanner) will give you a
    better scan than the Imacon.

    Interpolate.
     
  4. Supply the largest file you can, and let the LightJet interpolate to the final print size. It will do it better than any interpolation program you can use.

    Or, if you want a pixel-to-pixel match for the final image, have the film drum scanned to the exact file size you need for the LightJet.
     
  5. The Imacon has approximately a fixed number of pixels across the frame at maximum resolution. So the 24 mm side of 35 mm becomes 8000 pixels wide, the 4.5 cm side of 645 becomes about 8000 pixels wide and the 4" side of 5-4 becomes about 8000 pixels wide. (all approximate) The total file size then depends on the aspect ratio of the film - so 35 mm wins out.

    I notice a significant improvement in quality on the 949 when scanning 35 mm at 8000 instead of 4000 ppi. 4000 ppi isn't enough to get the best out of film, even fast film. Scanned at 8000 ppi and printed at 300 ppi is a 27x enlargement. That shouldn't need too much interpolation to give you 30 x 40.

    Best, Helen
     
  6. jem

    jem

    The highest res for 6 by 4.5 on an Imacon 949 is 4000 PPI giving approximately 190 Mb in 8 bit and 380Mb in 16 bit. Reproduces at 300 PPI to 32 by 254 inches at 300 PPI.

    For 35 mm, the highest res is 8000 PPI - giving a scans of 245 (b bit) or 490 (16 bit) and reproducing at 300 PPI to 37 by 25 inches.

    The Imacon 949 has far, far more *real* optical resolution than the Epsons, Nikons etc. This is easily visible in prints and anyone who has tested this sort of thing with any seriousness will confirm it.
     
  7. jeremy,

    how did you get those values?

    the max i got from 35mm is 20"x30" at 300dpi which is around 155mb.

    for 6x4,5cm is again 20"x30" or a little bigger at 300dpi and its around 100mb.

    ?

    i dont care about the mb value. the only thing i care is the dimensions at 300DPI.

    I dont underdstand your 4000ppi or 8000ppi. please give the dimensions in the format that i mention.

    width x height @ 300dpi = x mb


    and they are all scanned at 8bit.
     
  8. One step at a time:

    The highest resolution that a 949 will scan 35 mm at is 8000 ppi. Forget about the print resolution, just scan at 8000 ppi.

    On the short side (approx 0.94 inches usable) that leads to a scan about 7,500 pixels wide. At 300 ppi, that is 25 inches (ie 7500/300). The long side is 1.5 times that, so it is about 37 inches.

    Because of the way that the scanner works, the short side of the scan always ends up at around 7500 to 8000 pixels wide (the CCD arrays are 8000 pixels wide). Therefore, no matter what format you scan, the short side will always end up at around 25 inches if printed at 300 ppi. As the aspect ratio of 645 is 1.33 to one, the long side will end up at 25 x 1.33 = 33 inches.

    Best, Helen
     
  9. "Forget about the print resolution, just scan at 8000 ppi."

    I should have written:

    "Forget about the print resolution, just scan 35 mm at 8000 ppi and all other formats at maximum scanner resolution."
     
  10. thanks helen but at the end i cant get 30"x40" at 300dpi.

    i think i have to interpolate the image with lightjet 430.

    actually wondering if i scan these with a drum scan, since the mb will increase do you think the grain factor will increase too? if yes then its better to scan with imacon and then interpolate. so that you can get a much grainless image. i dont know about the sharpness issue though?
     
  11. I think that Edward gave you a good answer with the first post in your previous question: resample to 300 ppi from a 949 scan at the maximum optical resolution. It isn't a big step up to 30 x 40 from 25 x 37. Many people would suggest that you should just let the Lightjet system do it. The only reason that I do the interpolation myself is that I prefer to do the final sharpening myself, but it's no big deal.

    Once film scans are enlarged to the point where the graininess is showing, my preference is for high resolution scans - the higher the better. From 7000 ppi upwards the scan is beginning to be a good representation of the granular nature of the film. That's my opinion, anyway. So if you want the real maximum quality (a judgement call), try a drum scan at a higher resolution, but you may not see much difference. The best way would be to do comparative tests for yourself.

    Best,
    Helen
     
  12. I'm gonna skip the numbers. I scan 35mm Tri-x negatives at 4800 on my Flextight Precision and print 24 x 36 on a 7600 with NO problems of grain or sharpness. I'm using Atkinson profiles with Prem Luster.
    Richard (Brooklyn)
     

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