Medium format scanning??

  • Thread starter Thread starter A.F. Hobbacher
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A.F. Hobbacher

I have several rolls of 120 film (2 1/2 x 2 1/2 inch) which I am
planning to scan for archiving purposes. It is groups of people at
celebrations, of which the pictures require full resolution of the 120
format.

A scanning service offered scans at 4000 dpi, which would result in
about 300 MB files. That is to big to handle. What should I do? There
are some possibilities:

1. Have scans at lower resolutions? What is the loss?
2. Have it shipped on CDs or DVDs and wait for bigger computers in
future?
3. Let it compress, but at what ratio? Then store it and wait for
bigger computers?

Is there any hint?

Regards AFH
 
Use JPEG format for storage? Even though the JPEG algorithm is lossy, you
can control the compression and quality level with many applications, and
even at fairly high compression levels (on the order of 100 to 1), the
results on most "natural" images are often very good, and should be aided by
your high resolution.

s/KAM
 
I have several rolls of 120 film (2 1/2 x 2 1/2 inch) which I am
planning to scan for archiving purposes. It is groups of people at
celebrations, of which the pictures require full resolution of the 120
format.

A scanning service offered scans at 4000 dpi, which would result in
about 300 MB files. That is to big to handle. What should I do? There
are some possibilities:

1. Have scans at lower resolutions? What is the loss?
2. Have it shipped on CDs or DVDs and wait for bigger computers in
future?
3. Let it compress, but at what ratio? Then store it and wait for
bigger computers?

Is there any hint?
Click to expand...


Your math is a bit off. That's 243 Mbytes, not
quite 300. (Using 24 bit color.)

These aren't really such large files, by current
standards. Most current PCs and Macs are well
up to the job. I've been dealing with 160 Mbyte
files for the last three years, first on a 700 MHz
Athlon, now on a 1.6GHz machine.

I recently started dealing with 330 MByte files
from 4x5" film scans (2500 dpi.) These files are
slower to process, but still tolerable.

You can get around twenty such files on one DVD,
without compression.

High quality JPG compression will reduce the file
sizes by 60-70%.


rafe b.
http://www.terrapinphoto.com
 
I have several rolls of 120 film (2 1/2 x 2 1/2 inch) which I am
planning to scan for archiving purposes. It is groups of people at
celebrations, of which the pictures require full resolution of the 120
format.

A scanning service offered scans at 4000 dpi, which would result in
about 300 MB files. That is to big to handle. What should I do? There
are some possibilities:
Click to expand...


Perhaps there is more to it that you did not state, but "pictures
require full resoluton" does not have meaning by itself.
The valid question is "how large an image do you need for your goal?"

The size question can only be answered after you determine your goal.
The purpose for the image determines what image size is acceptable.

For example, if the only goal is to view the image on the computer
screen, then an image size that fits on the screen is appropriate.
From 120 film, 600 dpi will create an image larger than most screens.

If the goal is to print it, then the ratio of
(scanning resolution / printing resolution) is the enlargement factor.

Scan at 4000 dpi, print at 300 dpi, and you get 4000/300 = 13x
enlargement, which is 29 inches square from 56 mm film. If this is your
goal, then you need 4000 dpi. If it is not, then probably not.
 
At 2400dpi, my Scanmaker 5900 produces 100MB TIFF files scanning 645's.
The At 4800dpi (Epson 4870) would produce 400mb files, which would be too large
for archiving.
Could I expect similar print quality from the resulting scans, if I convert them
to JPEG for archiving?

Jeff.
 
At 2400dpi, my Scanmaker 5900 produces 100MB TIFF files scanning 645's.
The At 4800dpi (Epson 4870) would produce 400mb files, which would be too
large
for archiving.
Could I expect similar print quality from the resulting scans, if I convert
them
to JPEG for archiving?
Click to expand...


Opinions vary about use of JPG. Some people go berserk if they can detect
any sign of JPG artifacts at all. Others go berserk about 400 MB files.
There are a few of us that are berserk regardless of the subject. <g> The
only thing that is sure is that you will hear many different answers, and of
course, there are many different goals too. There is no single answer,
except that you must establish your own goal, and then a plan appropriate
for that goal.

To be as small as it is, JPG file compression is intentionally lossy,
meaning quality is always lost and it is unrecoverable. However, there are
degrees, and via the JPG Quality setting, a JPG may be poor and small, or it
may be OK and large. Sometimes small size is more important than quality,
and sometimes quality is more important than small file size. One should
learn to be able to recognize JPG artifacts, which really helps when forming
our own opinion.

We do have a setting for JPG Quality. Higher quality JPG (like 1/3 file
size instead of 1/10 file size) can be fine for many purposes, certainly for
printing purposes or viewing purposes (and it is still 1/3 file size, which
is a drastic difference). I would exclude editing purposes, meaning that if
you may need to ever edit and resave the image again, then JPG is not the
best choice. Meaning also that even if you do archive as JPG, keep it as TIF
until the last archiving step, and save it as JPG only the one final time.

Storage space is very inexpensive today, and I prefer to use TIF for
important archives, then there is simply no question about quality.
But opinions do differ about the tradeoff between size and quality.

I think the better answer is to simply rethink if 4800 dpi and 400MB is
necessary for your purposes. If you are printing wall murals, surely it is.
If you are printing 6x4 inch snapshots, then 6 MB uncompressed is plenty.
If you are viewing on the computer screen, 2 MB uncompressed seems like a
lot.

Scanning at 4800 dpi and printing at 300 dpi will give 16 enlargement, which
is about 3 feet from medium film. Again, if that is the goal, it is a good
plan. If it is not the goal, then there is likely another more realistic
plan.

There must be some reason you are scanning the image. You should archive
enough for your realistic future goals, we do need enough, but frankly, more
than is needed is not needed. That seems a much better answer than "the
absolute maximum regardless".
 
Well, one 400 mb file would fit with room to spare on a CD. Ten such files
would fit with room to spare on a DVD. Whether this makes them too large
for archiving depends on how many CDs or DVDs you wish to keep around.

And, of course, you can use non-lossy compression on Tiff files or with
Genuine Fractals files. These files are much smaller that the uncompressed
Tiff.

Jim
 
Recently said:
At 2400dpi, my Scanmaker 5900 produces 100MB TIFF files scanning
645's.
The At 4800dpi (Epson 4870) would produce 400mb files, which would be
too large for archiving.
Could I expect similar print quality from the resulting scans, if I
convert them to JPEG for archiving?
Click to expand...
To address a different aspect of your question: you've used the term
"archiving" a few times, now. If that is your goal, the best format to
archive your medium format images is on the film! Save yourself a lot of
grief, and get archival sleeves for the film, and store them properly. Not
only will it retain your image quality over time, but it will likely
outlast any digital media that you would store a scan. And, as you're
discovering, low-end scanners will compromise the resulting image,
regardless of the size of the file.

Regards,

Neil
 
Raphael Bustin said:
Your math is a bit off. That's 243 Mbytes, not
quite 300. (Using 24 bit color.)

These aren't really such large files, by current
standards. Most current PCs and Macs are well
up to the job. I've been dealing with 160 Mbyte
files for the last three years, first on a 700 MHz
Athlon, now on a 1.6GHz machine.

I recently started dealing with 330 MByte files
from 4x5" film scans (2500 dpi.) These files are
slower to process, but still tolerable.

You can get around twenty such files on one DVD,
without compression.

High quality JPG compression will reduce the file
sizes by 60-70%.


rafe b.
http://www.terrapinphoto.com
Click to expand...

What is the film? If Tri-X, or similar grain size, 2500-3000 dpi range
scans should be sufficient. LZW compressed tiffs will give you about
20% size reduction, without loss.
 
I'm not sure what the purpose of your "archiving" is. Assuming your talking
about color negative film, if the intent is to maintain maximum quality of
the images, then you will indeed need to scan at something close to 4000
dpi, but will also need to scan at 16-bit depth per color. This will result
in a 600 MB file uncompressed, and perhaps 400-500 MB with a lossless
compression such as TIFF with LZW. If you store with a lightly compressed
JPEG 2000 format (ordinary JPEG won't accomodate 16-bits per color) you will
lose some fidelity but probably reduce the file size by a factor of 3 or 4.

A worse problem, though, is that no matter what file format you choose, it
will be expanded to 8 bytes per pixel when read into most photo processing
programs with 16-bit depth. This will occupy 800MB of memory. While
photoshop, for instance, can handle that, with 2GB of memory it will quickly
revert to virtual memory when you start processing the image and become
*extremely* slow. This will probably change as 64 bit software and
processors, with multi-gigabyte memories, beome commonplace, but not now.

If possible for your purposes you might consider scanning at something like
1500-2000 lpi at 8-bit depth. This will by no means retain the full quality
of the film image, but should still produce good prints up to at least 8 x
10. You will likely lose highlight detail with the 8-bit format, though.

Don
 
Don said:
I'm not sure what the purpose of your "archiving" is. Assuming your
talking about color negative film, if the intent is to maintain
maximum quality of the images, then you will indeed need to scan at
something close to 4000 dpi, but will also need to scan at 16-bit
depth per color. This will result in a 600 MB file uncompressed, and
perhaps 400-500 MB with a lossless compression such as TIFF with LZW.
Click to expand...

Supposed you mean 35mm I think you are wrong. When I scan 35mm film at
4800 dpi, the files have about 160 MB at 48 Bit, 16 Bit infraread
channel included.

regards
Markus
 
A.F. Hobbacher surprised us all by writing:
I have several rolls of 120 film (2 1/2 x 2 1/2 inch) which I am
planning to scan for archiving purposes. It is groups of people at
celebrations, of which the pictures require full resolution of the 120
format.

A scanning service offered scans at 4000 dpi, which would result in
about 300 MB files. That is to big to handle. What should I do? There
are some possibilities:

1. Have scans at lower resolutions? What is the loss?
2. Have it shipped on CDs or DVDs and wait for bigger computers in
future?
3. Let it compress, but at what ratio? Then store it and wait for
bigger computers?

Is there any hint?

Regards AFH
Click to expand...

A "full resolution" scan from a Epson 4870 PHOTO scanner from a 6x9cm
negative is over 350 megabyte file! If you are lucky, you might fit two
on a CD!!!
Re-define what you want to do. save as JPEG. Compress files. WHat
purpose will "full resolution" serve for the future?

Douglas
 
A "full resolution" scan from a Epson 4870 PHOTO scanner from a 6x9cm
negative is over 350 megabyte file! If you are lucky, you might fit two
on a CD!!!
Click to expand...

Use DVD or firewire hard drives to archive.
Re-define what you want to do. save as JPEG. Compress files. WHat
purpose will "full resolution" serve for the future?
Click to expand...
It will make sure that should you need to return to the original you
still have one. I've seen too many mistakes made on original files
with no means of returning to the original to think that lossy saving
is a good method of archiving.
 
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