Digital BW, The Print

Hi Robbit,

> Okay, I've seen people referring to dpi for scanning which I guess is
> dots per inch, but on the actual scanner software (nikon) it is ppi,
> which is pixels per inch (I'm assuming) and ppi is used in photoshop
> as well. When people are talking about dpi are they actually
> referring to ppi...
> I've always said dpi, but now I'm wondering if dpi is the right term.
> Thanks for any info!
> Robbie

Technically, scanners scan SAMPLES per inch, or SPI, and MAKE pixels...but
there is no actual "resolution" for a digital image file...until you want to
output it, and then it's PIXELS per inch...so when you send a file to the
printer, or the screen, you specify the number of PIXELS per inch you want
it output at.  Printers (most of them anyway), on the other hand, print
DOTS, single solid colors, so they print in DOTS per inch.

But, when scanning, I guess you can say that scanners scan "dots", though
the definition of dot is different than that of a printer dot...

But, the really important note here is when outputting, your pixels per inch
gets translated to dots per inch via the printer driver, so it's converting
your full color/grayscale pixels to dots that solid ink spot(s) (typically
only one color per "dot") or no spot...doing what is called "halftoning" or
"dithering" to convert.  This can get very detailed, and may be more than
you want to know.

Regards,

Austin