Re: Optimal file resolution for Epson printers
Re: Optimal file resolution for Epson printers
- Subject: Re: Optimal file resolution for Epson printers
- From: Ernst Dinkla <email@hidden>
- Date: Sat, 15 May 2004 13:20:36 +0200
Roger Breton wrote:
In the same line, would 16 bit Photoshop files produce smoother
colors than 8 bit files?
Best regards,
Paul Schilliger
I would not think so because I believe the driver is still outputting as 8
bit. But I admit I never tried it.
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
There has been a discussion on the subject months ago. The three
main OSses around seem to restrict the throughput to 8 bit
anyway. So with the usual drivers/memory management you will not
get more than 8 bit input. However internally the driver
computation/tables are 16 bit where it adds quality, output per
inkchannel is 2 bits (must be more now with longer droplet size
ranges).
There are claims that ImagePrint accepts 16 bit input and gets a
better quality for that reason.
The 720 dpi output, 300 ppi input is Epson SC 9000 quality
roughly. Since then the printer droplet ranges are increased,
smallest droplet sizes reduced, 2880 dpi output is possible, 7
color printer models introduced, so the 300 ppi input will not
deliver the best quality possible anymore.
Qimage sets the optimum input ppi for different drivers/printers
and will interpolate/extrapolate to that number with a user
selectable method before it sends the file to the driver. The
pyramid method does it better than Photoshop bicubic etc so it is
wiser to let Qimage do the upscaling from an odd ppi number.
I wonder how much extrapolation is done in Imageprint as there
are several reports that there's a steady increase in quality
going from 180 to 720 ppi input even on the Epson 9600. In a
negative mood it could mean that the extrapolation method in
Imageprint is weak. I can't proof that but it should show in
lower ppi input images if compared to the Epson driver or other
RIPs.
Ernst
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