Digital BW, The Print

Hi Tony,

> On Mon, Feb 10, 2003 at 07:37:50PM -0500, Austin Franklin wrote:
> > What happens when you resample the image to accommodate some
> mythical PPI to
> > the printer is you degrade the image.  The printer dithering
> algorithm is
> > going to already resample the image simply to convert it to
> printer dots,
> > that's what dithering algorithms do.  Resampling the image yet
> another time,
> > as I said, degrades it.
> >
>
> I know little about these things but is it not possible that the printer
> driver resamples an image to a specific resolution before
> performing its own
> conversion to CMYK (or whatever inks it is using)?

I don't know what you are saying/asking.  It's a fact, the print driver HAS
TO resample the image to convert from pixels to dots, that's what a print
driver specifically does, in our case.

> In such an
> instance is it
> not also possible that if one presents an image to the printer driver
> already at that dpi then that resampling does not have to be done?

You are NOT presenting an image in DPI (Dots Per Inch) to the print driver.
You are presenting it in PPI (Pixels Per Inch).  Printers print in dots,
images are in pixels.  There is a conversion that has to happen to get from
pixels to dots.

By your comment I can conclude you don't understand how the pixel to dot
conversion is done (or that it even needs to be done!), and what dithering
is?  You might want to read up on it, and there are some very excellent
resources on the web that could explain it.  Adobe actually has a good
write-up on this, and if I can find it, I'll pass the URL along.  If you
would like me to explain somewhat I can, and possibly someone else can give
you some explanation as well.

> Given the choice of supplying my own resampled image to the printer driver
> and knowing the driver will not resample further

It doesn't work that way.  As I said above, you are sending PIXELS to the
printer driver, and it is converting to DOTS by the driver, then these dots
are sent to the printer.

Regards,

Austin