Comments at bottom.
At 6:32 PM +0000 6/29/02, olympus-digest wrote:
>Date: Sat, 29 Jun 2002 11:18:10 -0700
>From: Winsor Crosby <wincros@xxxxxxxxxxxxx>
>Subject: Re: [OM] Archiving digital data
>
> >Although one can buy CD ROM disks that will (at least in theory)
> >last hundreds of years, it strikes me that if one has much of a
> >library, periodically copying old disks to new formats to preserve
> >compatibility with future recording formats causes great logistics
> >problems.
> >
> >The issue isn't restricted to photos. I need to save everything, basically.
> >
> >My approach is bulk storage, so that conversion to a new format
> >takes one operation, not hundreds to thousands of manual operations.
> >Nor is any thought required, which is good, as I now have 12 GBytes
> >of files in 103,000 files and folders, some 18 years accumulation.
> >It may sound like a lot, but it all fits on one or two tapes,
> >costing ten or twenty dollars.
>
>- -snip
>
> >Joe Gwinn
> >
>
>Hope you saved your original images. If you did, pick out a good one
>and perform a scan of it with a current high quality scanner. Touch
>it up a little in PhotoShop if it has faded a little. Print it.
>Print your archived file of your 1985 scan. Compare.
All on moldy negatives? I assume that your point is that the 1985 negatives
(and prints) are still far better than anything scanned back then, which is
certainly true (at least for amateur grade stuff), unless the negative/print
has suffered in storage.
My point was strictly about the preservation of digital data. Actually, I have
no scanned photos or digital photos. I plan to stick with silver-based
photography for some time, as it will probably be at least ten years before
digital can equal silver, for a price even obsessed amateurs can afford.
Scanners with adequate resolution and color depth are only now becoming
economically practical.
The following posting from last year is relevant:
>Date: Thu, 20 Dec 2001 22:54:30 -0400
>To: olympus@xxxxxxxxxxxxxxx
>From: Joe Gwinn <...>
>Subject: New Olympus digital camera
>
>I looked up the datasheet of the Kodak KAF-5100CE CCD imager chip that Olympus
>will use:
>
>Its imaging area is 17.8 by 13.4 mm, or almost exactly one quarter of a 35-mm
>frame. There are 2614*1966= 5,139,124 pixels. However, there is a catch:
>These pixels are either red, green or blue, so we actually have only 1,713,041
>three-color resolution cells here.
>
>The pixels are square, 6.8 microns (0.00027 inchs) on a side.
>
>Let's take a lens with resolution of 60 lines per millimeter. Each such
>"line" is in fact a pair of lines, one black, one white. There are
>24*36*(2*60)^2= 12,441,600 resolution cells in a 24x36 mm frame. Each such
>cell has three colors. [So, 35mm film has 37.3 megapixels, if one rates silver
>based film as if it were a digital camera.]
>
>So, a 35-mm film image contains (12441600)/(1713041)= 7.26 times as much
>information as does the 5.1 megapixel image. Using Moore's Law, it will take
>Log2(7.26)*18= 51.5 months, or 4.3 years for Kodak's CCD images to equal 35-mm
>film.
>
>The dynamic range [of the imager] is quoted at about 70 dB, or about 12 stops.
> The dynamic range of film is more like 7 or 8 stops. The linearity and large
>dynamic range of silicon image sensors is why they have [largely] displaced
>film in astronomy.
>
>
>Kodak also makes the KAF-16801CE imager, whose sensitive area is square, 36.7
>mm on a side, with square pixels 9 micron on a side. There are 4080^2=
>16,646,400 pixels, each of one of the three colors, for a total of 5,548,800
>three-color cells. This chip likely costs thousands of dollars today, but in
>ten years they will be giving them away.
So, it won't be that long. But I'll still be using my OM-1, and enduring the
laughter of children.
Joe Gwinn
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