Digital BW, The Print

Do the following test:

take a sharply-focussed, highly-detailed, but *UNSHARPENED* (this is important) 
image of yours at 600 dpi (or more accurately 600 "spi": samples per inch) and print 
it at 8"x10" @ 1440dpi
then downsample it to 400 spi and print that
then downsample it to 200 spi and print that

and tell me if you see any difference. (I just did this myself, btw). Most people can 
readily see a difference with the 200 spi image, but can't see any significant 
difference between 400 and 600 (at least not at 1440 dpi output).

All things being equal, epson uses a custom stochastic dithering algorithm that is 
likely based on "something" in the neighborhood of 360dpi as its base from which to 
derive the dither. Send any more than that to the printer and the data is certainly 
DOWNSAMPLED by the printer. The test above more or less proves this. Stick with 
something in the neighborhood of 360 spi and you can't go wrong.

Michael Sullivan
author "Make Your Scanner a Great Design and Production Tool"


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "marcsien77" 
<marcsien77@y...> wrote:
> I would appreciate group members' opinion re. what is the optimum 
> resolution for grayscale images for a 1440 dpi inkjet output.  I have 
> seen a number of different recommended values such as 240, 360 or 
> 480ppi which left me a bit confused. Thanks in advance,
> Marc.