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settings for scanning 35mm negatives

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July 10, 2005 10:57:09 PM

Archived from groups: alt.comp.periphs.scanner (More info?)

Epson 2400 with film holder. P4, 3.2 with 2 gig of ram and 75 gig free
on hard drive.

Using Epson software - twain.

I would like to scan a 35mm negative at the highest resolution and color
depth possible so that when I work with it in Photoshop, I can get the
best possible quality.

My work will often involve extensive cropping and therefore, the final
photo will be only a small portion of the entire negative.

The Epson software gives me the option to scan as high as 48 bit and to
at a resolution of 12800. But when I try to actually scan at this high
end, my computer freezes although it "should" have enough power.

I seem to need to go down to 24 bit and either 4800 or 2400 resolution
for it to successfully save a scan.

Why can't I use the higher settings?

And, what would be reasonable settings to use to achieve good quality?
Do I need to scan at such a high bit rate and resolution?

TIA

Louise

More about : settings scanning 35mm negatives

Anonymous
July 11, 2005 4:06:43 AM

Archived from groups: alt.comp.periphs.scanner (More info?)

In article <MPG.1d3b3be22f626a29989899@news-server.nyc.rr.com>, Louise
<none@nospam.com> writes
>Epson 2400 with film holder. P4, 3.2 with 2 gig of ram and 75 gig free
>on hard drive.
>
>Using Epson software - twain.
>
>I would like to scan a 35mm negative at the highest resolution and color
>depth possible so that when I work with it in Photoshop, I can get the
>best possible quality.
>
>My work will often involve extensive cropping and therefore, the final
>photo will be only a small portion of the entire negative.
>
>The Epson software gives me the option to scan as high as 48 bit and to
>at a resolution of 12800. But when I try to actually scan at this high
>end, my computer freezes although it "should" have enough power.
>
>I seem to need to go down to 24 bit and either 4800 or 2400 resolution
>for it to successfully save a scan.
>
>Why can't I use the higher settings?
>
A couple of reasons.

Firstly, at 12800ppi and 48bit resolution, the entire image occupies at
least 1.3Gb of RAM. Windows itself occupies a fair bit, as well as the
TWAIN interface and applications, so perhaps there just isn't enough
memory to hold the entire file. The Epson TWAIN driver stores the image
temporarily in real RAM, rather that writing it to disk, so hardware is
sometimes a limitation, particularly if several frames are selected at
once.

There have been a couple of reports that the Epson driver encounters
problems with more than 2^30 bytes in the image, which is 1Gb - your
file is larger than this.

Are there any settings between 4800ppi/8bpc and 12800ppi/16bpc that
work? You might find the point that it falls over is just marginally
short of what you are trying.

>And, what would be reasonable settings to use to achieve good quality?
>Do I need to scan at such a high bit rate and resolution?
>
No, you don't need to scan at such high resolution. More importantly,
there is no advantage whatsoever in doing so. Your scanner has a
nominal resolution of 2400ppi. By half stepping the stepper motor it
can achieve 4800ppi in one axis, whilst interpolating the other axis to
get 4800ppi in that as well. Beyond 4800ppi everything, in both axes,
is interpolated - data invented by the software based on mathematical
rules applied to the real data. In practical terms, the maximum useful
resolution is 2400ppi, and even at that the contrast at the resolution
limit is negligible, so it is generally a complete waste of time using
anything more.

Whether you scan at 48-bit colour or 24-bit colour depends on how much
post processing you intend to do on the resulting image. You cannot
even see a full 24-bit colour range, let alone print it. But as much
overhead as possible is always useful if you intend to apply significant
alterations to the gamma and contrast of the image. Otherwise 24-bits
is more than adequate for almost all applications.

In fact, there is an outstanding challenge, which has never yet been
met, to produce an image using 48-bit scanning which could not equally
be achieved with 24-bit scanning and appropriate common sense in setting
the controls of the scanner.

So, for most of your purposes, the best you will get out of your scanner
will no be limited in any way by scanning at 2400ppi and 24-bit colour,
yielding a maximum image from a 35mm frame of about 3400x2268 pixels and
a file size of 23Mb - which your computer will handle very nicely.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)
July 11, 2005 4:45:43 AM

Archived from groups: alt.comp.periphs.scanner (More info?)

In article <FmDvAhCDoa0CFwwH@kennedym.demon.co.uk>,
rkm@nospam.demon.co.uk says...
> In article <MPG.1d3b3be22f626a29989899@news-server.nyc.rr.com>, Louise
> <none@nospam.com> writes
> >Epson 2400 with film holder. P4, 3.2 with 2 gig of ram and 75 gig free
> >on hard drive.
> >
> >Using Epson software - twain.
> >
> >I would like to scan a 35mm negative at the highest resolution and color
> >depth possible so that when I work with it in Photoshop, I can get the
> >best possible quality.
> >
> >My work will often involve extensive cropping and therefore, the final
> >photo will be only a small portion of the entire negative.
> >
> >The Epson software gives me the option to scan as high as 48 bit and to
> >at a resolution of 12800. But when I try to actually scan at this high
> >end, my computer freezes although it "should" have enough power.
> >
> >I seem to need to go down to 24 bit and either 4800 or 2400 resolution
> >for it to successfully save a scan.
> >
> >Why can't I use the higher settings?
> >
> A couple of reasons.
>
> Firstly, at 12800ppi and 48bit resolution, the entire image occupies at
> least 1.3Gb of RAM. Windows itself occupies a fair bit, as well as the
> TWAIN interface and applications, so perhaps there just isn't enough
> memory to hold the entire file. The Epson TWAIN driver stores the image
> temporarily in real RAM, rather that writing it to disk, so hardware is
> sometimes a limitation, particularly if several frames are selected at
> once.
>
> There have been a couple of reports that the Epson driver encounters
> problems with more than 2^30 bytes in the image, which is 1Gb - your
> file is larger than this.
>
> Are there any settings between 4800ppi/8bpc and 12800ppi/16bpc that
> work? You might find the point that it falls over is just marginally
> short of what you are trying.
>
> >And, what would be reasonable settings to use to achieve good quality?
> >Do I need to scan at such a high bit rate and resolution?
> >
> No, you don't need to scan at such high resolution. More importantly,
> there is no advantage whatsoever in doing so. Your scanner has a
> nominal resolution of 2400ppi. By half stepping the stepper motor it
> can achieve 4800ppi in one axis, whilst interpolating the other axis to
> get 4800ppi in that as well. Beyond 4800ppi everything, in both axes,
> is interpolated - data invented by the software based on mathematical
Thanks so much for the helpful description of what's "really" happening.

By shutting down almost all other running programs, I can - if I wish to
- go to 48bit by 4800 resolution saved as a tiff, although it takes a
while.

But my question now is: if I use 4800ppi, one axis is being
interpolated. Am I doing my photograph any favor at all by doing this?
Am I enhancing the final image (which I plan to adjust in Photoshop), or
am I filling my image with "interpolation" rather than quality?

Also, am I better off with tiff or psd since I plan to work with it in
Photoshop?

Thanks again.

Louise
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Anonymous
July 11, 2005 12:20:21 PM

Archived from groups: alt.comp.periphs.scanner (More info?)

In article <MPG.1d3b8d901054d8a998989c@news-server.nyc.rr.com>, Louise
<none@nospam.com> writes
>In article <FmDvAhCDoa0CFwwH@kennedym.demon.co.uk>,
>rkm@nospam.demon.co.uk says...
>> In article <MPG.1d3b3be22f626a29989899@news-server.nyc.rr.com>, Louise
>> <none@nospam.com> writes
>> >Do I need to scan at such a high bit rate and resolution?
>> >
>> No, you don't need to scan at such high resolution. More importantly,
>> there is no advantage whatsoever in doing so. Your scanner has a
>> nominal resolution of 2400ppi. By half stepping the stepper motor it
>> can achieve 4800ppi in one axis, whilst interpolating the other axis to
>> get 4800ppi in that as well. Beyond 4800ppi everything, in both axes,
>> is interpolated - data invented by the software based on mathematical
>Thanks so much for the helpful description of what's "really" happening.
>
>By shutting down almost all other running programs, I can - if I wish to
>- go to 48bit by 4800 resolution saved as a tiff, although it takes a
>while.
>
>But my question now is: if I use 4800ppi, one axis is being
>interpolated. Am I doing my photograph any favor at all by doing this?

The answer to that is in the part of above paragraph that you snipped:
"In practical terms, the maximum useful resolution is 2400ppi, and even
at that the contrast at the resolution limit is negligible, so it is
generally a complete waste of time using anything more."

>Am I enhancing the final image (which I plan to adjust in Photoshop), or
>am I filling my image with "interpolation" rather than quality?
>
There is some minor benefit to scanning at 4800ppi in that you are
collecting twice as many real data samples and thus improving the signal
to noise ratio of the scan in the same way as 2x multiscanning on a
dedicated film scanner. However you are unlikely to see any discernable
resolution difference. Interpolation actually produces a desharpening
effect, and the interpolation in one axis more than offsets the improved
resolution in the other.


>Also, am I better off with tiff or psd since I plan to work with it in
>Photoshop?
>
There is little difference for the scanned image and both formats are
losslessly compressed. Tiff files are more portable, but psd is a useful
intermediary format that will allow you to save all the Photoshop layers
and their interactions should you wish to change your edits in future.
However, when used in this way, psd files can become enormous. I would
recommend tiff formats in general unless you really need the options
that the psd offers.
--
Kennedy
Yes, Socrates himself is particularly missed;
A lovely little thinker, but a bugger when he's pissed.
Python Philosophers (replace 'nospam' with 'kennedym' when replying)
Anonymous
July 11, 2005 6:33:21 PM

Archived from groups: alt.comp.periphs.scanner (More info?)

"Louise" <none@nospam.com> wrote in message
news:MPG.1d3b3be22f626a29989899@news-server.nyc.rr.com...
> Epson 2400 with film holder. P4, 3.2 with 2 gig of ram and 75 gig free
> on hard drive.
>
> Using Epson software - twain.
>
> I would like to scan a 35mm negative at the highest resolution and color
> depth possible so that when I work with it in Photoshop, I can get the
> best possible quality.
>
> My work will often involve extensive cropping and therefore, the final
> photo will be only a small portion of the entire negative.
>
> The Epson software gives me the option to scan as high as 48 bit and to
> at a resolution of 12800. But when I try to actually scan at this high
> end, my computer freezes although it "should" have enough power.
>
> I seem to need to go down to 24 bit and either 4800 or 2400 resolution
> for it to successfully save a scan.
>
> Why can't I use the higher settings?
>
> And, what would be reasonable settings to use to achieve good quality?
> Do I need to scan at such a high bit rate and resolution?
>
> TIA
>
> Louise
>
Never scan at a higher resolution than the optical resolution of the
scanner.
Any greater value than the optical resolution causes software interpolation
which only "guesses" at the manufactured pixels.

If you need greater detail than your Epson 2400 offers, get a dedicated film
scanner.
Scanning at 48 bit is fine, but be aware, it doubles the files size with
little benefit.
http://www.scantips.com/basics14.html
The above page talks about 24 bit vs 36 bit, but 24 bit vs 48 bit would
apply.

For a good online source of information on scanning go to:
http://www.scantips.com

This page on Interpolated resolution - what is it?:
http://www.scantips.com/basics07.html
Is a good place to learn what interpolation is and why it is bad.

--
CSM1
http://www.carlmcmillan.com
--
July 12, 2005 8:20:08 AM

Archived from groups: alt.comp.periphs.scanner (More info?)

In article <RqvAe.418$zw4.168@newssvr12.news.prodigy.com>,
nomoremail@nomail.com says...
> "Louise" <none@nospam.com> wrote in message
> news:MPG.1d3b3be22f626a29989899@news-server.nyc.rr.com...
> > Epson 2400 with film holder. P4, 3.2 with 2 gig of ram and 75 gig free
> > on hard drive.
> >
> > Using Epson software - twain.
> >
> > I would like to scan a 35mm negative at the highest resolution and color
> > depth possible so that when I work with it in Photoshop, I can get the
> > best possible quality.
> >
> > My work will often involve extensive cropping and therefore, the final
> > photo will be only a small portion of the entire negative.
> >
> > The Epson software gives me the option to scan as high as 48 bit and to
> > at a resolution of 12800. But when I try to actually scan at this high
> > end, my computer freezes although it "should" have enough power.
> >
> > I seem to need to go down to 24 bit and either 4800 or 2400 resolution
> > for it to successfully save a scan.
> >
> > Why can't I use the higher settings?
> >
> > And, what would be reasonable settings to use to achieve good quality?
> > Do I need to scan at such a high bit rate and resolution?
> >
> > TIA
> >
> > Louise
> >
> Never scan at a higher resolution than the optical resolution of the
> scanner.
> Any greater value than the optical resolution causes software interpolation
> which only "guesses" at the manufactured pixels.
>
> If you need greater detail than your Epson 2400 offers, get a dedicated film
> scanner.
> Scanning at 48 bit is fine, but be aware, it doubles the files size with
> little benefit.
> http://www.scantips.com/basics14.html
> The above page talks about 24 bit vs 36 bit, but 24 bit vs 48 bit would
> apply.
>
> For a good online source of information on scanning go to:
> http://www.scantips.com
>
> This page on Interpolated resolution - what is it?:
> http://www.scantips.com/basics07.html
> Is a good place to learn what interpolation is and why it is bad.
>
Thanks - very helpful links.

Louise
!