Archive film scans

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>From: "Oskar" garbage@vondemhagen.de

>How do you archive film (24x36) scans? One of my possible choices is
>48bit RGB/4800dpi - that's lots of data (DVD-5 fits less than one
>film).

External hard drives. They are usually around $1 per gigabyte now and I see
them on sale at Fry's as low as 50 cents/gigabyte ... use at least two with
copies of your data on both, ideally kept in separate locations, since they'll
eventually fail but having two copies is safe.

>I posted a similar question in this group but did not get any comment.

IIRC you asked about different compressions for archiving, like 24 bit or
jpegs, and most people probably felt you shouldn't compress or convert to jpeg
at all, which is likely why you didn't get an answer.

If you're short on disk space it's probably a good idea to make the first set
of tonal corrections in 16 bit/channel mode and then converting to 8 bit since
saving 8 bit tiffs to cut the storage requirements in half, but few people
recommend going to jpegs (except maybe Littleboy).

Bill

Archived from groups: rec.photo.digital (More info?)

Thanks. The reasoning behind the idea using jpeg-compression was: The
effective resolution of the flatbed scanner is about half the nominal
resolution (according to the German c't magazine).
jpeg-compression will, therefore, not destroy much information.
Basically I think jpeg-compression of 16bit data would suit me and my
data best.
But for the time being I'll use 8bit-tif LZW compressed.
Oskar

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"Oskar" <garbage@vondemhagen.de> wrote in news:1102808401.316208.318410
@z14g2000cwz.googlegroups.com:

> How do you archive film (24x36) scans? One of my possible choices is
> 48bit RGB/4800dpi - that's lots of data (DVD-5 fits less than one
> film).
>

Before I started storing that much data, I would want to make sure that
there was really that much information. If you scale the data first, then
there won't be any point to saving 48 bits (apply levels and curves to
most of the images and then save as 24 bit). There could be some images
that you feel will benefit from the 48 bits with some new technology in
the future, and you should save those as 48 bit.

4800 x 3200 (roughly) is around 15 megapixels. Are your film equipment
and your techniqe really up to 15 Mp? I know that when I started making
enlargements of film bigger than 8" x 10" that it became really clear
that in most cases there just wansn't enough there. As I improved
technique and equipment I eventually got up 11" x 14", but that's about
all.

4800 / 300 = 16". That's a mighty big print. Do you really need that
resolution.

Again, there could be some particular images that you might feel very
strongly about, but are *all* of them that important to you?

I wouldn't trust anything to plastic discs with organic dye (DVD-R, CD-
R). Nothing that was that important, anyway.

Bob


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Archived from groups: rec.photo.digital (More info?)

>> How do you archive film (24x36) scans? One of my possible choices is
>> 48bit RGB/4800dpi

>From: bob usenetMAPS@2fiddles.com
>
>4800 x 3200 (roughly) is around 15 megapixels.

He's scanning at 4800 dpi so should be getting around 6,800 x 4,400 pixels or
almost 30 Mpixels, so 90 MBytes in 8 bit mode or 180 MB in 16 bit mode per
image.

As someone who has wrestled with archiving medium format scans up to 550 MB I
feel his pain  

>Before I started storing that much data, I would want to make sure that
>there was really that much information.

Excellent point, since I think he's scanning with a flatbed.

>I wouldn't trust anything to plastic discs with organic dye (DVD-R, CD-
>R). Nothing that was that important, anyway.

Another good point ...

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bhilton665@aol.comedy (Bill Hilton) wrote in
news:20041213204753.16189.00002001@mb-m02.aol.com:

>>4800 x 3200 (roughly) is around 15 megapixels.
>
> He's scanning at 4800 dpi so should be getting around 6,800 x 4,400
> pixels or almost 30 Mpixels, so 90 MBytes in 8 bit mode or 180 MB in
> 16 bit mode per image.
>

Oh. I got my metric conversion factor confused! For some stupid reason I
was thinking 3.54 cm per inch.

There are probably few lens/film combinations that can make use of 6800 x
4400 pixels, even with flawless technique.

Bob

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Archived from groups: rec.photo.digital (More info?)

Yes the scanner is a flatbed (Epson Perfection 4870 Photo). An
affordable way to scan 35mm and medium size. (And it delivers much more
detail than my old CanoScan 2700F with its nominal 2700dpi.)

Many of my slides are Kodachrome 25. I think they deliver even more
detail than the scanner can extract.

My - possibly naive - intention/reasoning was:
The resolution of the scanner has reached a level where there is little
room for improvement (given the quality of the film). Why not archive
all films - and reduce the fear that the negatives/slides might be
destroyed. (But maybe the storage media are not up to that challenge
yet.)

The resolution is not for printing but for detail/zoom on a computer
monitor.

One of the things I (thought I) learned, correct me if I am wrong, is:
Of two files with equal (file) size, the one with maximum resolution
and jpeg compression is always better than the one with lower
resolution but without compression.

Oskar

Archived from groups: rec.photo.digital (More info?)

"Oskar" <garbage@vondemhagen.de> wrote in news:1103069561.813206.172830
@z14g2000cwz.googlegroups.com:

> One of the things I (thought I) learned, correct me if I am wrong, is:
> Of two files with equal (file) size, the one with maximum resolution
> and jpeg compression is always better than the one with lower
> resolution but without compression.
>

I don't know about "always," but in general yes, a bit more resolution with
a bit more compression is usually better than a bit less resolution with
less compression.

Here's a specific example: 1024x768 with very heavy compression will almost
always look better than 320x240, even with no compression at all, for a
given print size.

As to your original question, I suppose it's really up to you. If you have
the time and the money to deal with such large files then you can. I know
my slide collection has a few images that are worthy of 90mb files, but I
also know that many of them are not; there's no reason you can't use a
variety of sizes to store the data. Slide film is pretty contrasty, too. It
might make sense to scan it at 48 bits, but it probably makes as much sense
to adjust the levels and then convert it to 24 bits for storage.

Bob

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