Scan-Resolution steps and quality in SF with Topaz 2

[typestar]

I'm working now on a Linotype-Hell Topaz 2 with Silverfast 6.6.2 on OSX 10.6.4 Snow-Leopard.
I want to scan some very "fine" stamps in very high resolution and a scaling factor of 500% for real huge
output on Epson LF with about 50x60 cm

As far as I see inside Silverfast, there are some "fixed" Resolution Steps":
300 ppi, 635 ppi, 1270 ppi, 2540 ppi and 5080

So, my only concerns are about quality in the results:

For this work, I can use the very middle of the scanner, which is reserved for 2540 and 5080 ppi OPTICAL resolution.

1)Are this some kind of "reserved, fixed" resolution-steps combined with the Linotype/Heidelberg physical optics?

2)If I scan with 720 ppi or 1440 ppi (as this would be good for Epsons LFprinting output) -
as this is over 635 ppi and over 1270 ppi ill this result in some
kind of Silverfast "interpolation" of data - or will there be NO difference in quality?

3) As the stamps are line-art, which in best case are all scanned in very high resolution-
is it better to to use the "Silverfast" fixed steps of 1270 / or 2540 ppi instead of 720 / 1440 ?
Or is it better to re-sample/downsize the size in Photoshop?

4) for this kind of super fragile stuff: Is it better "only" to scan very high-res with 2540ppi or even 5080 ppi
and NOT to use in addition a scaling factor inside silverfast (let's say of 400 %) or would it be "better" to have it
with NO scaling-factor --- would there be a quality-concerned difference in the final results?

Thankyou for your professional answers,
Thankyou for your helpout and advice:

Christian

[LSI_Morales]

Dear Christian,

For this work, I can use the very middle of the scanner, which is reserved for 2540 and 5080 ppi OPTICAL resolution.

1)Are this some kind of "reserved, fixed" resolution-steps combined with the Linotype/Heidelberg physical optics?

Yes, those are fixed steps provided by the scanner itself, the highest optical resolution of the scanner is 5080 dpi on the small area in the center of the scan surface.

2)If I scan with 720 ppi or 1440 ppi (as this would be good for Epsons LFprinting output) -
as this is over 635 ppi and over 1270 ppi ill this result in some
kind of Silverfast "interpolation" of data - or will there be NO difference in quality?

Yes it will use the next higher optical step and then downsample to reach the desired output. However If I were you I would not use such a high printing resolution, actually 300 dpi is photo resolution for printing, more than that can not be discernible by our eyes but at very very short distances or with the help of a magnifying glass.

Since you are already enlarging something very small, it does not make any sense to use such a printing resolution because the details are already enlarged. My advice, 300 dpi will more than suffice if the pictures are to be observed from a distance of 50 cm or so.

You will even need to use a printing resolution of 250 dpi or similar to be able to achieve the desired level of enlargement without the help of interpolation.

3) As the stamps are line-art, which in best case are all scanned in very high resolution-
is it better to to use the "Silverfast" fixed steps of 1270 / or 2540 ppi instead of 720 / 1440 ?
Or is it better to re-sample/downsize the size in Photoshop?

Since quality is your main concern, I would simply use the highest optical resolution to create a raw file and then from that file create the printing copies.

4) for this kind of super fragile stuff: Is it better "only" to scan very high-res scanned 2540 or even 5080and NOT to use in addition
a scaling factor inside silverfast (let's say of 400 %) or would it be "better" to have it
with NO scaling-factor --- would there be a quality-concerned difference in the final results?

Absolutely right, if you use the highest optical resolution and you add a scaling factor of more than 100% you will be interpolating the image. No scaling factor should be used in this case.

Cheers