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

["Hemingway, David J" <HEMINGD@polaroid.com>]

One of the new features of the upcoming release of Polacolor Insight is the
ability to use one of several decimation techniques from nearest
neighbor(lowest quality) to bicubic(highest quality also longer). Your
choice would depend on use.
David

 -----Original Message-----
From:   SKID Photography [mailto:skid@bway.net] 
Sent:   Tuesday, October 23, 2001 5:10 PM
To:     filmscanners@halftone.co.uk
Subject:        Re: filmscanners: RE: filmscanners: Re: Hello, thanks, and
more.

Arthur,
You bring up interesting points.  I have never actually done side by side
comparisons of the PS or scanner
downsampling to see if there is a noticeable difference.  However, I have
not comprehended a difference by 'my
memory' (always a scary proposition) going either way.  I will try to do
some side by side comparisons and
report back.

Another aspect to could affect the differences between the cheaper and
slightly better scanners, beyond the
software, is the mechanical qualities....Like the better machine having a
better (more well calibrated)
stepper motor.

Harvey Ferdschneider
partner, SKID Photography, NYC




Arthur Entlich wrote:

> 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
>   >
>   > .
>   >
>   >