Selecting DPI For Printing - How ?

Archived from groups: alt.comp.periphs.scanner,comp.periphs.scanners (More info?)

I have been reading that an image scanned at 1200 dpi can be printed out
at 300 dpi to obtain a reasonable quality enlargement.

I don't have a dpi selector on my hp deskjet 3420 driver. Is their a
work around for this ?
Thanks.

Micko
2 answers Last reply
More about selecting printing
  1. Archived from groups: alt.comp.periphs.scanner,comp.periphs.scanners (More info?)

    In article <421e15a5@212.67.96.135>, -@-.- says...
    >
    >
    >I have been reading that an image scanned at 1200 dpi can be printed out
    >at 300 dpi to obtain a reasonable quality enlargement.
    >
    >I don't have a dpi selector on my hp deskjet 3420 driver. Is their a
    >work around for this ?


    Scaling later in a photo editor as CSM described is one way. Scan at 1200
    dpi 100%, and scale later
    (scale as opposed to resample, these are different concepts)
    to 300 dpi to create a 4x size print.
    Or it is the same thing to scale later to the 4x size inch dimensions,
    which will then print at 300 dpi. Specify one and the other follows.

    Another way is to specify what you want in your scanning software:

    Specify the 300 dpi and 400% size (or specify the inch dimensions to be 4x
    larger than the original). If this enlargement factor is other than 100%,
    then the meaning is that the dpi value is the Printing resolution instead
    of the Scanning resolution (if 100%, they are the same value).
    If 400%, then the scanner will scan at the specified 300 dpi x 400% = 1200
    dpi in order to create sufficient pixels to print at the specified 300 dpi
    at 400% size.

    Said one more way, the two images
    300 dpi at 400% size
    1200 dpi at 100% size

    are the same image. Both scan at 1200 dpi, and both are the same
    dimension in pixels. The only diffence is that one image is already
    scaled to print 300 dpi 4x size, and the other (if printed as is without
    additional scaling) will print 1200 dpi at 1x size. The only difference
    is the simple dpi instruction to the printer of how the pixels are to be
    spaced on paper (which is scaling).

    --
    Wayne
    http://www.scantips.com "A few scanning tips"
  2. Archived from groups: alt.comp.periphs.scanner,comp.periphs.scanners (More info?)

    "Micko" <-@-.-> wrote in message news:421e15a5@212.67.96.135...
    >I have been reading that an image scanned at 1200 dpi can be printed out at
    >300 dpi to obtain a reasonable quality enlargement.
    >
    > I don't have a dpi selector on my hp deskjet 3420 driver. Is their a work
    > around for this ?
    > Thanks.
    >
    > Micko

    You open the image in a image editor such Irfanview and in the print dialog,
    you set the printing parameters to print the image to whatever size you want
    the final print to be.
    http://www.irfanview.com
    Get the plugins, Irfanview needs them.

    You do not resize, which lowers the number of pixels. You print the image
    using all of the pixels available.

    In Irfanview and other image editors you can tell the print driver what
    exact size you want the image to be on paper.

    All of the math is performed in the software. You may have a choice of the
    quality of the print in the printer driver, such a best, normal or draft,
    that effect how good the quality is.


    --
    CSM1
    http://www.carlmcmillan.com
    --
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