Digital BW, The Print

Doug,

just a note to say your tests pointed in the right direction. You pretty much 
answered your question: The Epson driver  internally reses up whatever you 
give it to the "ideal" res for the printer. Not so with OPM.

In my tests I found a bigger improvement simply going to 720 dpi  rather than 
switching from 8 to 16 bit - but your conclusions are valid nevertheless. I didn't 
do all the permutations you did.

OPM started life as 16bit  and added 8bit compatibility very recently. This 
move may have introduced some new  problems. My sense is that if in doubt, 
OPM "likes" 16bit, period. But an 8bit/720 file may be more manageable.
 
As for the dpi, since OPM doesn't do any internal changes to the image data, it 
is often beneficial to feed a file that matches the hardware dpi . Hence the 
choice of 720. But I have found that, depending on the image, you can go a lot 
lower (in the 400s) and not see a difference. 360 can get dicey with sharp 
edges that are not perpendicular.

As always, let the folks at bowhaus know what you find or other suggestions 
by writing directly to them (rather than relying on the list). They are working to 
improve the software, so good  feedback helps.

Antonis




--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Doug Nielsen" 
<douglasnielsen@e...> wrote:
.....

> 
>  I did a series of prints of a particularly troublesome section of my test file 
varying 
> Bit-Depth and Resolution. The test file was originally 8-Bit/240 dpi (which by 
the way 
> printed very well through the Epson 2200 driver but poorly through OPM). I 
printed 
> the section all the way up to 16-Bit/720 dpi. My conclusions were that, to the 
naked 
> eye, increasing the resolution to 480 dpi at 8-Bit or just converting from 8 to 
16-Bit 
> yields a satisfactory print. With  an 8x loupe, the criteria increases to 
8-Bit/720 dpi or 
> 16-Bit/360 to 480 dpi.  I think I could still see improvement even up to 
16-Bit/720 
> dpi, although only marginal improvement.
> 
> The results indicated that changing from 8 to 16-Bit yields roughly the same 
> improvement as doubling the resolution. So, for the Milkweed print at 16-Bit, 
I am 
> seeing about the same fidelity as when I print at 8-Bit/720 dpi. The results 
with my 
> test file are comparable."
> 
> Doug Nielsen
> Epson 2200
> MacOSX 10.2.6/Classic 
> Blue&White G3