Scanner resolution for halftones

Discussion in 'Scanners' started by Ray K, Apr 11, 2006.

  1. Ray K

    Ray K Guest

    I'm making photo nametags for a high school reunion. The source photos
    come from the yearbook, with each 8.5 x 11 page containing six b&w
    photos. When scanning I use the descreen option, then save the scans
    (Visioneer .max files) as jpg (quality=100) files. Then I use the Irfan
    program to view the complete page and crop all but one of the graduate's
    photos. I resave the cropped photo, again as a jpg (quality=100) file.

    (As I type this, I realize that I should be cropping the .max files, so
    there would be only a single conversion to jpg. Irfan gives me very
    precise dimensions as I select the area to be cropped; the Visioneer
    PaperPort software doesn't. As I think more about it now, I could do
    more precise trimming directly on a jpg file with the Word 2002 program
    I use to create the nametags and print them.)

    Head size is about 1.6" in the yearbook and 1.25" in the nametag, or 78%
    of the original. On the nametag, the photo is about 1.4"W x 1.6"H.

    Even though the photos are b&w on the nametags, I'm using a color inkjet
    printer(Canon i550) because I add a colored border around each picture.
    Paper stock is a soft gloss Kodak Picture Paper, PP-1-A. I'll probably
    use Canon Photo Paper Plus Glossy for the final nametags, because of its
    much better sharpness.

    The owner's manual give the following printer specs:

    Printing resolution: 4800 x 1200 dpi max (ink droplets can be placed
    with a pitch of 1/4800 inch at minumum.) [Doesn't say minimum what.]

    Graphic image printing:
    Data format:
    Canon extended mode: Raster image format
    Canon extended mode: 300, 600, 1200, 2400, 4800 dpi

    Print Head:
    Black: 320 nozzles (600 dpi)
    Cyan, Magenta, Yellow: 256 nozzles (1200 dpi)

    By looking at the yearbook photos with a 10x loupe, I count about 100
    dots per horizontal inch. If I count along a 45-degree angle, the count
    goes up to about 140 dpi. I can't make such measurements on the output
    of the Canon because the "dots" aren't just black; they are a seemingly
    random pattern of the three other colors.

    Any suggestions for best scanner and printer resolutions, to give
    maximum sharpness (like retaining the two glints in the eyes from the
    photographer's lights)?


    Ray K, Apr 11, 2006
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  2. Ray K

    Ray K Guest

    Scanning each individual image would be a nightmare. I'd have to
    precisely locate each image in the scanned area. And overall, it would
    take much longer, even though scanning one image is faster than scanning
    the whole page.

    Even with tight cropping so just the head is visible, having the nametag
    image the same size as in the yearbook would force me to use a 3x4"
    nametag, which is a bit too large. Instead, I'm using a 2.25x3" tag,
    which dictates a slight reduction in image size.

    Thanks for the suggestions and the links to scantips. Wayne has done an
    excellent job.

    Ray K, Apr 12, 2006
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