Archived posting to the Leica Users Group, 2002/07/15

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Subject: RE: [Leica] Update on Nikon 8000ED scanner
From: "Austin Franklin" <darkroom@ix.netcom.com>
Date: Mon, 15 Jul 2002 12:54:38 -0400

Hi Henning,

> Usually, it's best to scan at the highest resolution the scanner can
> handle;

Some scanners offer higher resolution than their native/optical resolution,
and interpolate the data they output.  Scan at the OPTICAL/NATIVE
resolution, which may or may not be the "highest".

> ...If you now send 720dpi or anything above
> 500dpi to the printer pads the file with no useful information. It
> slows things down, but doesn't send more real information.

You don't send "dots" to the printer, you send pixels.  Scanners scan
samples per inch, and output pixels to the computer...and pixels per inch
are what you send to the printer, and printers print in dots per inch.  Some
printer drivers CAN take much higher resolution data, up to 720 in my
experience, and you get an improved image.

> As others have noted, 360dpi is a reasonable maximum to send to a
> 1440 or 2880dpi printer.

I don't understand why "maximize" it.  Send what ever you send, there are no
magic numbers to send to the current Epson inkjet printers...and
interpolating the data will simply degrade it, and your resultant output
will be degraded also.

> 360dpi is close to the maximum that paper
> prints can resolve, in any case.

Well, I've used up to 720 and get better results...and typically send in the
400+ range, and again, results are improved.  It is VERY dependant on the
image, and of course, the driver.

> So.... the best thing usually is to import your hi-res scan, do your
> Photoshop layers, curves, etc, resize to 8x10 at 360dpi and then do
> your sharpening.

That will interpolate the data, and degrade the image.  Whether you can see
the degradation or not is image and size dependant.  Let the PPI (PIXELS per
inch) fall where it may.  BTW, PS uses the term "pixels per inch", not "dots
per inch" in their resize dialogue box.

> ...and will give you
> the best quality.

My experiences differ, as I've noted, and I get the best quality as I've
stated above.  I also believe Jon Cone et al, give the exact same advice,
and as I have, I know they have printed thousand of thousands of
prints...and done a lot of experimentation to arrive at these conclusions.

Regards,

Austin

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