Re: Scanning Photos

[markbau1@aol.comQQQQyuk (MarkBau1)]

My mistake, I thought you were talking about posting a pic at 150ppi rereading
your two posts it seems like you are advocating scanning higher then resampling
to a lower ppi which is in fact the way to go. You didn't mention that you are
posting the pic at less than 150.

<<<If you're so conversant with the whole topic, please tell us all the
difference between PPI and DPI...>>>>

Until very recently scanning was done for the single purpose of preparing an
image for press. Thus, the term dpi was always used as it related to the line
screen you were going to press with. Now we scan photos that are never going to
be viewed on anything but a monitor. Monitors do not have dots, they have
pixels, so when talking about displaying an image on screen you are talking
about how many pixels will display the image.

Most scanning software still uses the generic term dpi but some newer software
is using the much more correct term of spi, (samples per inch) which is what a
scanner is actually doing when it scans. After the scan you use dpi if you are
going to press or ppi if the image is intended for screen display.

To sum up:
A scanner's resolution is measured in samples per inch

A printer or imagesetter's resolution is measured in dots per inch.

A monitor's resolution is measured is pixels per inch.

Mark.


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http://home.earthlink.net/~markbau/