Digital BW, The Print

In a message dated 5/4/02 2:17:39 PM, AZinn@... writes:

>I need clarification regarding the maximum dpi of a file the Epson 
>printer uses. Is it correct to say that the printer only uses up to 
>240dpi files to output to 1400dpi, etc. ?  Or should that be that the 
>printer driver only uses 240dpi?  Is the printer capable of accepting 
>higher dpi files with a different driver?  I recall seeing some 
>discussion of this and may have it confused or am not stating it 
>clearly. 
>
>In the Pieziography manual it says: "Although images print with 
>clarity at 240dpi, there will be a remarkable increase in detail if 
>you can obtain your images at 720 dpi and higher."  I don't know if 
>that means the detail is gained at the larger print sizes with higher 
>rez scans which is the conventional way of expressing it or that the 
>piezo driver gets the printer to use more of the scanned dpi above 
>240 - which I doubt it does.

It indeed does. Even the standard Epson drivers support use one bit files up 
to 720 dpi. But when you start mixing areas of high contrast and those with 
many levels in 8 bit per channel files, the variable resolution of modern 
dithering algorithms makes it difficult to state just what resolution can be 
printed. The dpi in the Cone Driver is signnificantly higher than that of the 
Epson drivers (since it uses all heads for the same color channel, and 
eliminates any redundancy) allowing files of high resolution to produce even 
finer results. But that needs to be significant resolution, not empty noise, 
to make a difference.

C. David Tobie
Design Cooperative
CDTobie@...