>From: Denton Taylor <denton@xxxxxxxx>
>
> "I am new to this scanner thing and I thought that you should scan
>at 600dpi and print at 600 or better."
>
>Don't open THAT can of worms! :-) I'm in the field, so I'm biased, but I
>think ANYONE who is contemplating doing ANYTHING with images and computers
>could study Shannon and Nyquist.
>
>Basically, dot matrix printers use creative marketing. The 1440 you see
>advertised is a white lie. True, it can pack 1440 dots into an inch, but
>each one cannot be any one of the colors in the printer's gamut. Typically,
>such printers fill a 4x4 matrix with CYMK dots to achieve about 200 lines
>per inch for arbitrary colors.
>
>Also, when scanning, you need to scan at a minimum of twice the desired
>output line grid to preserve its detail. This is the so-called "Nyquist
>number," and is why audio CDs are sampled at 44 kHz when no human can hear
>anything above 22 kHz.
>
>What does this mean? For "same size" work, scanning at above 400 samples
>per inch is a waste, and scanning above 200 samples per inch doesn't buy
>you much. The value of such high scan densities is if you intend to blow it
>up. You can blow up a 600 spi scan by a factor of three with little impact
>on the output.
>
>Personally, I sample at 300 spi for same-size printing, then run the Epson
>at 720, which is REALLY only 360, at best, on perfect paper.
>
>
>: Jan Steinman <mailto:jans@xxxxxxxxxxx>
>: 19280 Rydman Court, West Linn, OR 97068-1331 USA
>: +1.503.635.3229
spi. Is that squirts per inch? :-)
Winsor
Winsor Crosby
Long Beach, California
mailto:wincros@xxxxxxxxxxx
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|