Digital BW, The Print

Hi Mark,

The conversion from PPI to DPI is called dithering, or halftoning...not
interpolation.  In the process of dithering, it may very well use
interpolation as part of the pixel to dot conversion.  At least with the
Epson driver it does, where, as you state, it interpolates the NPPI to
720PPI (at least for the "desktop" printers), and then derives it's dither
from the 720PPI data.

Regards,

Austin

> wouldn't that be called "nearest neighbor interpolation" :)
>
> mark
>
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Colorado Light"
> <coloradolight@w...> wrote:
> > That's not interpolation, it's just that a printer uses more than
> one dpi to
> > make a ppi.  Your print still has just 220 ppi.
> >
> > ----- Original Message -----
> > From: "Mark Hahn" <markhahn2000@y...>
> >
> > > I find that I generally need at minimu 220ppi original image data
> to
> > > get a good b&w print... with certain images and interpolation and
> > > processing I can sometimes get away with much less.  300ppi seems
> > > unquestionably good.  The Epson printer driver then interpolates
> up
> > > to 720 so there might be something to sticking to fractions of
> that
> > > or interpolating up to 720... but in the casual experiments I've
> done
> > > using different interpolation schemes I have't seen any *real*
> > > improvement which makes it worth the time (do the math... you can
> end
> > > up with some huge files)... but others disagree.
> > >
> > > mark