At 08:48 12/7/00 -0500, Nikolai Vladychevski <[EMAIL PROTECTED]> wrote:
>> > Nikolai
>> Often these "model" sites and p0rn sites and so on, use a very high
>> resolution scanner (1200dpi not interopolated) like a drum scanner to get
>> the image quality you see here, including the glossyness.
>I also have scanner that can scan at 1200. I don't know if it is
>interpolated (probably not because it is cheap)

It probably IS if it is cheap. The uninterpolated (optical) scanning
resolution and the sensitivity of the CCD are the major limitations on
quality in scanning.

Cheap scanners include hardware interpolation to provide you with
higher-resolution image files, but they are not extracting any more data
from the source image. In fact, the quality is actually reduced in the
process, because the lower-resolution but more accurate original optical
data is now smeared around in the interpolated file.

The scanner manufacturers like to print the final (interpolated) resolution
in large letters on the box to make you think you have a better product,
but the fine print optical resolution is what you should be looking at.

For the best quality you should be avoiding interpolation where possible,
which probably means you won't be scanning at the maximum output resolution
of your scanner.

As for sensitivity, better quality is generally more sensitive. Scanning
transparencies also gives you better quality than reflective originals.
Given that sites specialising in photos of models probably use high-qulity
scans of high-quality originals, it's going to be very hard for you to
compete in quality using a cheap flatbed scanner and small magazine photos...

>but do you think if I
>scan at 1200 (or even at 2400) I could make better quality photos than
>if I scan at 300?

Probably not a lot, if the original image quality is poor. The main area it
is likely to help you with is avoiding moire patterns due to the optical
interaction of your scanner's resolution and any screen or pixelation in
the original. But other than that, you are never going to get more useful
image information out of the scan than was in the original. If you are
scanning a postage-stamp-sized image from a magazine, there is only a very
limited amount of information in it in the first place. It is not likely to
have a screen resolution of more than about 150 lpi (if that).

>I tryed to scan at 1200 then applied pixelize filter
>and then resized to 150x200 pixels(72dpi) but didn't achieve any visible
>quality increases. Also, I don't know if retouching at higher depths
>helps more than retouching at 300 dpi.

Well, yes and no. There may be some benefits in the greater control given
to you by the higher resolution, but if 
the image quality is bad, you may be retouching many details that you don't
want in the final image, that don't actually show up in the lower
resolution version, thereby wasting time.

>I also found some info on interpolation, it says it is usefull only for
>line art:

The point about interpolation was that you should be avoiding it, and that
the good quality scanners don't do it, but that yours probably does.

The way I see retouching of poor-quality low-resolution images is that
there is so little of the information you want in the final image actually
present in the original, and that you have to fill in the rest yourself,
that you are effectively painting, not retouching. And in that case, why do
you need the original? If someone gave you a run-down shack and asked you
to turn it into a mansion, you'd probably start by bulldozing the shack.



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