Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and more.

[Arthur Entlich <artistic@ampsc.com>]

Harvey,

If I'm reading your comments (below) correctly, the only difference
between your old scanner and your new one in this matter is how the
software operates.  A 72 dpi scan at 200% making a 8 x 12" screen image
is the exact same thing as a 144 dpi scan of a 4 x 6" print.  And you
don't need Photoshop if you are going to do it that way.  It is possible
your new scanner has better downsampling software, also, which makes
the process easier.

In both cases, however, you might not be getting the optimum scan
quality from the scanner hardware. Neither 72 nor 144 is a native
divisor of standard flatbed optical resolutions, which usually are 300,
600, 1200 dpi...

That's where Photoshop can be helpful, because it's software is very
good at downsampling (and upsampling, BTW) using the bicubic formula.

Personally, I probably wouldn't do either of the approaches mentioned
above to get best results.  I would use optical resolution of the
scanner, or at least an exact divisor to 300, 150, and then downsample
in Photoshop, unless the scanner is actually scanning at full optical
resolution and downsampling afterward.

Studies have shown that using this approach gives the best "reduced
size" scan in most cases, based upon people's perception of the image.
If speed is absolutely most important, then scanning at 75, 100 or even
150 dpi is preferred, as native scans of 600 dpi, for instance, are
slower and take up large file spaces.

Art



SKID Photography wrote:

  > "Maris V. Lidaka, Sr." wrote:
  >
  >
  >>Screen dpi is not necessarily 72dpi - it depends on the size of the
screen and what resolution you set your monitor to - consider a 17"
monitor at 600x800 pixels v. set at 1200x1600 pixels - the second will
have double the dpi of the first.
  >>
  >>Ignore dpi for web use - pay attention to the pixel dimensions of the
image only, e.g. 480x640 or whatever.
  >>
  >
  > No matter which set of parameters (pixel count or 72 dpi) you still
end up with images of different sizes on monitors set on to different
resolutions.  It finally makes no difference which set you use.  I say
use whichever is more comfortable
  > to you.
  >
  > When we scan for web viewing, we scan at 72 dpi, to whatever final
dimensions we want the image to be.  If we want a 4x6 print to be viewed
at 8x12, we would scan it at 200% and 72 dpi.  We use a 42 bit Microtek
Scanmaker X12 USL scanner, ant
  > it works well.  On our old, cheaper 24 bit Umax we could not do
this.....On that one, we needed to scan at full resolution and then
convert in Photoshop.
  >
  >
  > Harvey Ferdschneider
  > partner, SKID Photography, NYC
  >
  > .
  >
  >