Digital BW, The Print

"Yes, when you send an image at 600ppi to an Epson 1280 printer using the
Epson driver, your image is upsampled to 720ppi by the driver using Nearest
Neighbour interpolation (unless the driver has other options such as DCC
which use a better interpolation). If you sent it an image at 1200 ppi (half
the size without resampling) it would be downsampled by the driver to
720ppi. Then the driver would turn the image into dots and print at whatever
quality(printer resolution) you chose (720,1440,2880, 5760dpi)."


Thanks. So it really doesn't matter what I send to the printer, the printer
will always upsample or downsample to 720 dpi. I never knew that, I always
thought the printer printed the same dpi as the ppi I sent to it, e.g. if I
sent it 600 ppi it would print 600 dpi at whatever printer resolution I
chose. I assume though that it's still better to send more ppi to it so that
the amount of upsampling is minimized or is that not correct either?

----- Original Message ----- 
From: "Bob Frost" <bob@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Friday, November 12, 2004 12:37 PM
Subject: Re: [Digital BW] dpi and stuff



Yes, when you send an image at 600ppi to an Epson 1280 printer using the
Epson driver, your image is upsampled to 720ppi by the driver using Nearest
Neighbour interpolation (unless the driver has other options such as DCC
which use a better interpolation). If you sent it an image at 1200 ppi (half
the size without resampling) it would be downsampled by the driver to
720ppi. Then the driver would turn the image into dots and print at whatever
quality(printer resolution) you chose (720,1440,2880, 5760dpi).

Epson mentions these 'input ppi' on page 24 Note 2 of
http://files.support.epson.com/pdf/pro10a/pro10aps.pdf

Other inkjet manufacturers apparently use different input values.

Bob Frost.


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