Resolution question (Newbie)

Discussion in 'Scanners' started by Peter McVries, Jul 18, 2003.

  1. I recently got a Canon LIDE 20 for scanning family album pics and so on to a
    digital format. I can set the resolution to a max of 1200 dpi. This
    results in a *lot* of RAM being used and big file sizes. Now, I want these
    pictures to be of decent quality...but is 1200 dpi overdoing it?

    Also, I've been saving them as a mixture of JPEG (with very low compression)
    and TIFF (LZW compression). Is this the best/most often used format to save
    pics or is there a better one?

    Peter McVries, Jul 18, 2003
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  2. Peter McVries

    Wayne Fulton Guest

    Resolution is used for enlargement. The ratio of
    (scanning resolution / printing resolution) is the enlargement factor.

    For example,

    Scan at 600 dpi, print at 300 dpi, for 600/300 = 2X size (double size)
    Scan at 300 dpi, print at 300 dpi, for 300/300 = 1X size (original size)
    Scan at 150 dpi, print at 300 dpi, for 150/300 = 1/2X size (half size)

    Or scan at 2700 dpi, print at 300 dpi, for 2700/300 = 9X size.
    9X is about 8x12 inches (about A4 size) from full frame 35 mm film.

    So, if you are scanning small film, probably you need the 1200 dpi.

    If you are scanning prints, and plan to print them original size,
    yes, 1200 dpi is overdoing it, try 300 dpi.

    If you are scanning prints, and will only view them on the screen,
    then you need even smaller images, to fit on your screen, so then
    try maybe 100 or 150 dpi.

    It doesnt get better than TIF for image quality, but for modems (web or email
    use) then the small size of JPG is normally required.

    The web site below is about these basics.
    Wayne Fulton, Jul 18, 2003
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