Digital BW, The Print

I know that we should generally print files (On the Epson) with a resolution at or near 350 
PPI. My question is what are the negative effects of using a higher resolution? If I opt not to 
throw out any data when re-sizing an image and the resolution ends up around 450 PPI, 
will this give me a lesser image than if I down-sized to 350?

Thanks - Ben

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ben_zlotkin"
<ben@b...> wrote:
> 
> I know that we should generally print files (On the Epson) with a
resolution at or near 350 
> PPI.
Not exactly true. The native resolution of the 2200 (and all Epson
desktop models) is 720 ppi and the Epson printer driver will
automatically interpolate incoming data to this value before printing.
Hence, having your file at 720 ppi resolution (or a lower value
derived froman integer divisor (e.g., 360 or 240 ppi) is where you
should be aiming.

Many people will go to the trouble of interpolatiing "all the way" to
720 ppi _before_ sending the file to the printer under the assumption
that their software algorithm (PS or Qimage, etc.) can do a better job
than the (presumably inferior) method used by the Epson driver. That's
what I generally do.


>My question is what are the negative effects of using a higher
>resolution? 

None, other than it might be a bit stressful (at least temporarily) on
your hard drive and/or RAM capacity. Of course there's no need to
archive your images at the higher resolutions.

 If I opt not to 
> throw out any data when re-sizing an image and the resolution ends
up around 450 PPI, 
> will this give me a lesser image than if I down-sized to 350?

No, higher is better, but best not to work with such "odd" values (see
above).

Phil
> 
> Thanks - Ben

Phil,

Thank you for an excellent answer - Im scanning 6x7s at 4000 spi and will do some tests 
at 720 at my desired print size tonight. 

The math makes sense, and Im not sure why it never occured to me before now.

_ Ben 

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Phil Rose" <pjrose@f...> wrote:

> 
> --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ben_zlotkin"
> <ben@b...> wrote:
> > 
> > I know that we should generally print files (On the Epson) with a
> resolution at or near 350 
> > PPI.
> Not exactly true. The native resolution of the 2200 (and all Epson
> desktop models) is 720 ppi and the Epson printer driver will
> automatically interpolate incoming data to this value before printing.
> Hence, having your file at 720 ppi resolution (or a lower value
> derived froman integer divisor (e.g., 360 or 240 ppi) is where you
> should be aiming.
> 
> Many people will go to the trouble of interpolatiing "all the way" to
> 720 ppi _before_ sending the file to the printer under the assumption
> that their software algorithm (PS or Qimage, etc.) can do a better job
> than the (presumably inferior) method used by the Epson driver. That's
> what I generally do.
> 
> 
> >My question is what are the negative effects of using a higher
> >resolution? 
> 
> None, other than it might be a bit stressful (at least temporarily) on
> your hard drive and/or RAM capacity. Of course there's no need to
> archive your images at the higher resolutions.
> 
>  If I opt not to 
> > throw out any data when re-sizing an image and the resolution ends
> up around 450 PPI, 
> > will this give me a lesser image than if I down-sized to 350?
> 
> No, higher is better, but best not to work with such "odd" values (see
> above).
> 
> Phil
> > 
> > Thanks - Ben

As Phil mentioned the 350 number is incorrect. Also, there are many
pre-2200 Epsons that have a native res of 360.
However, the notion of a reres to those numbers is driver dependant.
Tests are advised, and if you see no advantage to reresing your files
to print it's best to keep them at their native (scanner or camera)
res. Someday you may have a different driver, or a bigger printer, or
one with a different native res.
With some drivers, interpolation errors from unusual dpi's have been
reported, the Qimage users report their own circumstances, and I find
that the RIP here does the best job of scaling from any input file
size/res on it's own.
Best to test.
Tyler

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "ben_zlotkin"
<ben@b...> wrote:
> 
> I know that we should generally print files (On the Epson) with a
resolution at or near 350 
> PPI. My question is what are the negative effects of using a higher
resolution? If I opt not to 
> throw out any data when re-sizing an image and the resolution ends
up around 450 PPI, 

> will this give me a lesser image than if I down-sized to 350?
> 
> Thanks - Ben