Scanning 8x10 glass negs in 2 passes

Discussion in 'Photoshop' started by Gene Palmiter, Jul 7, 2004.

  1. I will be doing some photo prep for a book in the next couple of days. One
    thing I was asked about is whether I can scan 8x10 glass negatives. My plan
    is to scan with my Epson 3200 and scan it in 2 passes. PS-CS has some sort
    of panoramic stitching built-in....I will RTFM.

    Does this sound feasible? Anybody out there done anything similar? Any
    problems to expect?
     
    Gene Palmiter, Jul 7, 2004
    #1
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  2. I know some scanners (or rather the firmware or drivers) auto-adapt the
    scanned image, adjusting colour and/or contrast and such. I am not sure you
    will like that to happen.

    If I scan things in parts I include a small graycard-like piece of paper in
    the scan, that allows me to check for possible changes in scan results.
    Photoshop CS Stitch works quite well for me. just make sure you have enough
    overlap and indeed check the manual or some tutorials for the best stitch
    results.

    I have the photoshop for photographers book with tutorial cd, it has a nice
    videotut on stitching as well. (Amazon, now just over 30 bucks)

    Pjotr
     
    Pjotr Wedersteers, Jul 7, 2004
    #2
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  3. Gene Palmiter

    Mike Russell Guest

    This should not be a problem. Try to disable the scanner's auto exposure so
    that the tonalities of the two halves will match. I just posted some
    procedures in the "Grayscale Transform" thread for using curves to match two
    adjoining images that should provide fine tuning if it is needed.

    Another alternative is to photograph the negative with a digital camera,
    thus getting the entire image in one pass. If you have many negs to do this
    could save a lot of time and the results will probably be sharp enough for
    book reproduction.

    Once you have your images, do be careful about the dynamic range issue.
    Many glass negatives, particularly large format, were made before enlarging
    was common, and they were intended to be contact printed on "Printing out
    Paper", which relies on light to create the image, requiring no development.

    As the darker areas of the print are exposed, they inhibit further darkening
    of the in those areas. This greatly extends the tonality of the dark areas
    of the print. With modern printing materials, it is very easy to get a
    harsh result..

    Photoshop makes this easy to deal with, using curves. Steepen the quarter
    tone, and add another point to knock down the three quartertone, and you
    should see considerable detail retrieved in the shadows.

    It's not unusual to see scans of old images that were printed ignoring this
    effect, and the results are sadly very harsh, even though the information
    exists in the original negative.
     
    Mike Russell, Jul 7, 2004
    #3
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