How big do you scan a 35 mm original?

Discussion in 'Digital Cameras' started by sheepdog 2007, Sep 22, 2007.

  1. The thread where I started out to explain why pixel dimensions are
    meaningful to me while dpi is not made me question my (amateur)
    scanning technique. Have I been missing some quality by not scanning at
    a higher resolution on my inexpensive desktop scanner?

    I decided to do a test today. The original was a mediocre image,
    literally the first 35 mm slide out of the first box I came to. I
    scanned it once at about 3600 px wide, then my usual 1800.

    The quality of the raw scans is shabby compared to what a high-end
    drum scanner can do, and there were NO Photoshop tweaks applied, other
    than saving both as JPEGs in the size you see, down-sampled to 1080
    pixels wide, with the same amount of compression.

    See if you can guess which is which before I say any more:

    http://web.mac.com/olddognewtrick/iWeb/Site/scantest_070922.html
     
    sheepdog 2007, Sep 22, 2007
    #1
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  2. Not if you restrict the image quality to 1,000 pixel screen width! You
    might as well claim there was no point in buying a fast car because in
    your careful testing they all went at the same speed down the local high
    street in the rush hour.
     
    Chris Malcolm, Sep 23, 2007
    #2
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  3. sheepdog 2007

    ray Guest

    To answer the question: I generally scan everything in at a fairly low
    resolution. Those I want more detail, I rescan at a higher setting. Save
    disk space and time.
     
    ray, Sep 23, 2007
    #3
  4. sheepdog 2007

    ray Guest

    Disk space is cheap. Time is not.
     
    ray, Sep 23, 2007
    #4
  5. Crop 1 has more sampling artifacts than crop 2.

    Look, for example, at the lowest red petal in each picture -- about 1/3 of
    the way from the left side of the image.

    The lowest edge of that petal has more "jaggies" in crop 1 than it does in
    crop 2.

    Also, look at the second-from-the-bottom green leaf along the right edge of
    the image (which is actually near the upper right, despite being second from
    the bottom). That leaf's left edge has a distinct yellow outline; the
    leaf's right edge has a distinct blue outline. That's chromatic aberration.
     
    Andrew Koenig, Oct 3, 2007
    #5
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