Damaged image files

Discussion in 'Digital Cameras' started by MikeM, Feb 23, 2006.

  1. MikeM

    MikeM Guest

    Several months ago I bought my first digital camera. I backed up all
    photos to DVDs as soon as I downloaded them from the camera so I
    should have good copies of all downloaded images.

    The photos I took on a recent trip,SHQ JPGs, were downloaded to a
    portable HDD each night of the trip and viewed on a laptop. At that
    time there we no damaged files, none with the bottom part of the image
    missing or unreadable on the XP laptop. The 320 G HDD I used in a
    portable case is now a permanent drive in my computer, running XP.

    I left a copy of all the images on the hard drive and processed them
    with PSE4, most only with unsharp mask, some with auto contrast, and a
    small percentage were lightened. The number of damaged files has been
    slowly increasing. I have been rearranging them on my HDDs, but not
    processing them further.

    I have a large number of scanned slides and negs, TIF format, on the
    same drive. They are years older and have been processed more and
    moved around more than the digital images but are showing no signs of
    damage, apart from the ones damaged when a disk crashed a few years
    ago.

    I assume something on my computer has a bug that is causing the
    damage, but I don't know why only the images from the digital camera
    are being affected. Is it possible the different formats, JPG vs TIF,
    could be the reason?

    I have checked my hard drive a number of times but no problem has been
    detected.

    The nightly downloads were all backed up to DVDs with the laptop
    before I returned home, but I can't check them again because they are
    still at my daughter's place in Scotland.

    Thanks
    Mike
     
    MikeM, Feb 23, 2006
    #1
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  2. MikeM

    snapper Guest

    Sounds to me like that hard drive is slowly dying. Buy a replacement NOW and copy what you can to
    the new drive. The damaged files will stay damaged. And cross your fingers that the backups are
    OK.
     
    snapper, Feb 23, 2006
    #2
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  3. MikeM

    Hunt Guest

    I concur. You might want to take a look at SpinRight (www.gibsonresearch.com,
    IIRC), and run it. One caveat on workflow. You did part of it correctly with a
    BU to other media, but one should also NEVER work on their originals. I always
    make a folder for Originals, and then one for Work, then one for Finals, and
    maybe below that hierarchy, one for 8-bit, followed by RGB & CMYK, if the
    client needs it. This will leave you with the BU of the originals, plus a set
    on the HDD, untouched.

    Hunt
     
    Hunt, Feb 23, 2006
    #3
  4. MikeM

    MikeM Guest

    The drive the photos are on now is the HDD I bought just prior to
    heading overseas in Nov 2005 to be used as a portable backup, so I
    thought it should be safe for a while, but couldn't think of any other
    reason for this sort of problem . Maybe I got a dud drive.

    I made copies of the files which I then used to work on with PSE4.


    Mike
     
    MikeM, Feb 23, 2006
    #4
  5. MikeM

    Martin Brown Guest

    I hope you verified them against the disk at that stage.
    Bad idea to overwrite the originals in any case.

    But this is worrying. The possible causes are a dodgy hardware driver
    altering bytes or something nasty like a virus corrupting files as they
    are copied. If it was a read error from disk you would expect CRC errors
    and the "abort,retry,cancel" message from time to time.

    Various diagnostic programs exist to check for these faults. At a basic
    level one thing you could try as partial insurance is to copy everything
    to a new directory and hope that the intermittent fault does not occur
    indepenently on both of the copies at once. Knowing exactly what the
    defects look like might well shed light on the root cause.
    A wrong byte in an incompressed TIF file affects a single pixel and you
    are unlikely to see it at all. A bad byte in a JPEG affectes the entire
    of the rest of the image from that point onwards.
    It might be worth asking her to load a few images that you know to be
    bad on your hard disk to establish if the DVD holds good copies.

    I suspect that the disk drive has a problem with writing certain bit
    patterns to disk (very rare but not entirely unknown). Back up
    everything you hold dear as a matter of urgency.

    It is remarkable that the OS will boot if disk corruption is running at
    a high level as even the swap file should be vulnerable to write errors.

    Regards,
    Martin Brown
     
    Martin Brown, Feb 23, 2006
    #5
  6. MikeM

    Dave Cohen Guest

    If a file is successfully written, any subsequent corruption will cause an
    error when reading. I'm not sure if the initial write is verified. The crc
    check algorithm used is very powerful.
    Dave Cohen
     
    Dave Cohen, Feb 23, 2006
    #6
  7. MikeM

    MikeM Guest

    I'm glad I asked this question. I didn't know about that difference
    between TIF and JPG.

    On my UK-European trip I planned to use RAW or TIF but because of the
    card space taken up by those formats with my 7 mp camera I decided to
    use SHQ JPGs at maximum resolution.

    I should probably save the original JPG files as TIF.

    When not travelling have I tried using RAW but Olympus Master and PSE4
    saved the files to JPG or TIFs that didn't look as good as a JPG or
    TIF saved in-camera. Is this common/normal for files from an Olympus
    C-7070?


    Mike
     
    MikeM, Feb 24, 2006
    #7
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