Best way of preserving your digital images?

My belief is that the best backup policy is to diversify, diversify, diversify. The underlying principle is that if one backup set breaks, the others likely won't be ... if they're diversified.

What does this mean?
Don't keep all your sets on the same type of media. (What if it turns out the media you chose has some serious long-term issues that was only discovered yesterday?)

Don't keep all of your sets in the same geographic location. (What if you keep them all in your home, but the unexpected happens? Theft, fire, flood ...) I think a hybrid hard disk + a Hyperdisk disk memory strategy works well.

CD and DVD Longevity: How Long Will They Last? Good reading

For digital files, there are many file formats in use and no assurances that any will survive for 30 years. But most digital photographs today are stored in JPEG format, the compression standard used by most consumer digital cameras and supported by just about all the current imaging hardware and software. The digital-imaging industry is very unlikely to drop this support for it for a long time, even after better things come along. So store at least one copy of all your photos as a JPEG. Remember that just opening, viewing and closing a jpg file does NOT degrade the quality. It is only when you edit and save the edited picture that any degradation occurs.(JPEG Myths and Facts. Don't believe everything you hear about JPEGs. Read the facts here

Having said that I have to confess I store most of my master files as TIFF. JPEG uses lossy compression, which means that a decompressed image is not exactly the image you started with. Shoot and store one copy of your images at the highest quality and resolution your camera allows. If you plan to manipulate your images, convert them to a lossless format, such as TIFF, while you edit, then save the back to JPEG when you are finished if you do not have enough space on your harddrive to keep them as TIFF

With today's ( January 2013) price level of TB hard drives and Hyperdisk disk memory there is really no excuse any more not to save your master files as TIFF.

From Steves Digicam I Quote October 2004: "
What's the Bottom Line?:
The JPEG image format offers a way to save images using less space, but with some loss in image quality. Typically, a first generation save will be almost as good as a lossless TIFF as long as you use quality levels close to the highest available. Some "die hards" claim that you should never use a camera in JPEG mode when you have TIFF or RAW available as an option, and one cannot argue that you get the best quality and best editing capability with TIFF or RAW when compared to JPEG. That said, JPEG is a perfectly valid format to use even when capturing images the first time in your camera, especially when memory space, shooting speed, or the ability to print images without post processing is important. Remember that JPEG's are processed and ready to view/print, whereas RAW images require post processing to "develop" the images from the raw data. This takes additional time and can complicate your shoot-to-print workflow. A first generation JPEG will offer quality comparable to any other final or ready-to-print format, however, cannot offer latitude for correcting exposure and other shooting issues like a RAW image or a 48 bit TIFF. Bottom line: choose what works for you, but be sure to take the pros/cons of each format into consideration.
— Mike Chaney "

Tiff format for archiving digital images and CD-R for backing up!

TIFF Format (Tagged Image File Format)
TIFF Format Specifications:
TIFF is a tag-based image file format that is designed to promote the interchange of digital image data. The TIFF format originated in 1986 when Aldus Corporation and leading scanner vendors worked together to create a standard file format for images used in desktop publishing. The first version of the specification was published in July 1986. Version 6.0 of the specification was completed in September 1995. One can download both the original PDF and all supplements from this Adobe's Web site .

TIFF is primarily designed for raster data interchange. Its main strengths are a highly flexible and platform-independent format, which is supported by numerous image-processing applications. Since developers of printers, scanners and monitors, designed it has a very rich space of information elements for colorimetric calibration, gamut tables, etc. Such information is also very useful for remote sensing and multispectral applications.

Another feature of TIFF, which is also useful, is the ability to decompose an image by tiles rather than scanlines. This permits much more efficient access to very large imagery which has been compressed (since one does not have to decompress an entire scanline).

Theoretically, TIFF can support imagery with multiple bands (up to 64K bands), arbitrary # bits per pixel, data cubes, and multiple images per file, including thumbnail subsampled images. The old 'unofficial TIFF home page has not been updated since 1995, and is full of link rot. To replace it, the TIFF community has helped AWare Systems to build a new TIFF home, including a TIFF FAQ, tag directory, mailing list archive, and much more. This is all available from here!
Best Uses for TIFF Images
The most common file format that popular imaging applications support, and not to forget the printing industry, is TIFF. You can save both RGB and CMYK files in TIFF-format and TIFF is supported both by Mac and PC. TIFF format also saves your mask channels and in Photoshop supports 24 channels. Even more impressive is the nowadays with Photoshop 6 it also supports several layers. When you save a file with layers you check "layers" in the "Save as" dialogue box. The TIFF dialogue box in Photoshop 6, lets you, as one alternative, choose the lossless LZW compression. It is a lossless compression and you usually get a file that falls somewhere between 1/3 and 2/3 as large as the original. However LZW is pretty old technique. I would be inclined to store in tiff with zip compression instead of LZW. One problem is that Photoshop is still one of the few programs supporting ZIP in TIFF-files for the moment.

Backing up:
Don't forget that TIFF format is a lossless compression compared to JPEG. Use always a lossless 24-bit format as TIFF (or PNG, PPM, etc) while working on the image, then JPEG it when you are ready to file it away or send it out on the net. If you expect to edit your image again in the future, keep a lossless master copy to work from. The JPEG you put up on your Web site should be a derived copy, not your editing master.

Therefore I always save my original files, as master copies, in TIFF-formats, in spite if that most digital cameras store the images as JPEG'S, and save and back them up on a CD-R disk. And for all of you, who are shooting RAW files and converting to 16-bit tiffs, it is a must, if you are not going to lose all that information.) Not a CD-RW as you accidentally can overwrite your originals. There's considerable information on CD-R stability. Life expectancy is measured in decades not year, as in a century or more. I am told! It is very inexpensive but not perfect. Writing to a CD-R is a two-step process, and scratching a CD-R is easy. However the main reason I like CD-R is that it is a universal format. The makers of hard drives, Zip Drives, and CD's all say these media will last a very long tome if you handle them properly. but that will not matter if you do not have a device that reads them. Ten years from now, we may not have USB ports, Zip Drives, or any of today's media cards, but I bet that you will have a drive that can read a 5.25-inch optical disc. There is too much content out there for them to disappear quickly. I will not recommend any DVD formats yet, because the standards war are still raging.

Will your grandchildren be able to figure out what those shiny round discs in the shoebox in the attic really are?
("The Mitsui Photo Worried About Your CD-R Disc Archive? This week's Sunday Morning Photographer column, (May 09, 2004) might just save you some major grief in the near future. Lately there has been a lot of talk about CD-R corruption and failures. Want to know what the best brand of CD-Recordable discs is and where to get the "gold?" -- give Mike's column a read. Maybe MAM-A the leading manufacturer of quality recordable CDs and DVD, is maybe the only archival available nowadays?
Note: CD-R was a good way to archive images. You can find more information on following links.
-Andy McFadden's CD-R FAQ
-Recording LP records to CD-R FAQ
-Other CD-R FAQ (Goggle search)
-Things you should Know about CDs

Can I archive my raw-files?

The public, archival format for digital camera raw data Raw file formats are becoming extremely popular in digital photography workflows because they offer creative professionals greater creative control. However, cameras can use many different raw formats — the specifications for which are not publicly available — which means that not every raw file can be read by a variety of software applications. As a result, the use of these proprietary raw files as a long-term archival solution carries risk, and sharing these files across complex workflows is even more challenging.

The solution to this growing problem? The Digital Negative (DNG), a new, publicly available archival format for the raw files generated by digital cameras. By addressing the lack of an open standard for the raw files created by individual camera models, DNG helps ensure that photographers will be able to access their files in the future

File Formats for Digital Masters , a very informative article by The Research Libraries Group, a nonprofit coalition of universities, libraries, and archives, maintains some excellent pages
What do they say about archiving photo images in the newsgroups? I have collected some questions and answers hear

Archiving Images: Approaches to Storage & Retrieval by Michael H. Reichmann at The Luminous landscape.
Everyone has their own approach to image storage and retrieval. Today's 6MP digital cameras produce 18MB RAW files, and at about 30 Megabytes for each scanned 35mm frame even the largest built-in hard disk fills up quickly. How to store, index and safely archive all of these files? There are a number of conflicting issues, including cost, convenience and speed of retrieval, and finally, security. What to do?
Photographers have several choices, each with benefits as well as downsides. Here is my current approach. It has recently changed — and I'll explain both what I used to do, and what I now do to store, retrieve and archive my work.

At last my personal advice.
Save in TIFF format. You'll probably take the pictures in JPEG format, but plan to save them in TIFF format on your hard disk. TIFF is preferable to JPEG because the latter is a "lossy" format. You'll lose image information each time you change and resave a JPEG file. TIFF is a "lossless" format, so image quality will not be degraded. So don't ever save your master file as JPEG if you plan on doing any more editing to the image in the future as each recompression destroys a little more detail, rather like photocopying a copy then photocopying that copy etc .

Tip: Do you find TIFF files too large? If so, check to see whether your image-editing software offers a lossless compression option, such as ZIP. That will make the image files smaller without losing valuable data. I quote from the Photoshop guru Bruce Fraser: " I've been using TIFF with ZIP compression for both layers and background as my standard format for about 4 years now.... TIFF stores everything that PSD can hold, and it always contains a flattened composite so even if the TIFF reader can't understand layers it should be able to read the flattened version. ZIP-compressed TIFFs are typically about the same size as PSD saved without backwards compatibility (no composite), and much smaller than PSD caved with the composite.&

Save the master file. Even a large computer hard disk can quickly fill up with numerous image files. Yet it's important to save the master file: the original, unedited image. Saving the master file without changes lets you return to the original image later to make a third version, with special effects, for example.

(Note: Comparison of typical file sizes produced by the 8-megapixel Nikon Coolpix 8700 with 3,264x2,448-pixel image size.
RAW (12-bit NEF) 11MB
HI (8-bit RGB TIFF) 23MB
FINE (High-quality 8-bit RGB JPEG) 3.6MB
NORMAL (Standard 8-bit RGB JPEG) 1.6MB
BASIC (Highly compressed 8-bit RGB JPEG) 0.9MB)

Checking your CDs!
One way, of course, would be to copy the contents of the CD back onto your hard disk, which can be a slow process. However, there's a free utility, CD Speed 2000, available from CD Speed. You can i.e. perform a surface test before you start backing up. Or a quality check. (This is part of the same mob that produces Nero, the CD/DVD writing software package; CD Speed comes as part of the Nero Suite).

CD Tips- Things You Should Know About CDs and the proper care and handling of CDs - you won't believe this

DVD And CD Longevity Examined! Recently, scientists at the National Institute of Standards and Technology (NIST) looked at CDs and DVDs to see how long digital information recorded on to them would survive. They concluded that most CDs and DVDs will last 30 years or more if handled with care, but many factors can slash their longevity. However,a big part of the problem is that nobody really knows exactly how they're going to age, and there are many other factors at play. Researchers can simulate what they think will happen in 20 years, but unless you've got a large sample of DVD-Rs that are 20 years old (which you don't) you're not going to know for sure.
From The Nordic Museum in Sweden i quote and translate January 2006:

How to preserve your old images?
CDs are NOT a solution for long term storage of digital images. For occasional and short term storage you can use CDs, provided they are stored correctly ( not exposed to moisture, sunlight and so on.).

For long term storage you need to renew the media, on which the images are stored. Instead buy an external hard disk which today is affordable. For US$ 140 you get one with 1 TB to connect to your PC and which you can use for back-up.

Note. This museum has digitized a lot if images with the purpose to preserve them for generations to come

IBM expert warns of short life span for burned CDs (Burned CDs have a life span of between two to five years, storage expert says January 2006)
What happens with a JPEG image if you resave it 600 times? Look here, only rubbish
If you have the file in Raw-format how can I save space? I have already mentioned before but...With Adobe DNG lossy compression the user can half the file size at full resolution with minimal artefacts and all of the flexibility of raw. The question the user must ask themselves is - does every file need to be saved at full, lossless compression file size? Probably not. But rather than archiving 8-bit lossy compressed JPEGs why not archive the more flexible, higher quality, lossy compressed DNG files?

This page was updated January 19 Year 2013.