Facts of life: there are many ways to store your photos on digital media. In this article, PMA magazine takes a look at CD, DVD, media card, flash memory drive, and hard drive alternatives.
On their 50th wedding anniversary: (1) Will that CD be readable, so their grandchildren will be able to see the pictures? (2) Will the technology be available to do so?
In the early days of CDs, there were some very real concerns about the lifespan. In some cases, the life of a CD could be measured in months. Today, that's not nearly the concern it used to be. Or is it?
The problem is there's been no standard testing methodology, no CD-equivalent to Wilhelm Imaging Research Inc. (www .wilhelm-research.corn), Grinnell, Iowa. So notes Ron Kubara, vice president, National Account Sales, Noritsu Canada Ltd., Richmond, British Columbia, Canada, who has studied CD lifespan for years, and whose article on it appeared in Photo Marketing in September 2004.
"Nobody has taken on research into CD lifespan like Wilhelm has for prints, although more and more organizations are getting involved."
That all changed in late July. The Optical Storage Technology Association (www .osta.org) and Ecma International (www .ecma-international.com) announced they have joined to finalize an industry-wide, archival-grade, optical disc specification.
The OSTA Optical Disc Archival Testing (ODAT) Committee has worked with a multi-national group of industry experts to develop a draft specification for an archival standard. This committee is composed of global manufacturers of 120mm optical media and drives, as well as university and government members. Participating manufacturers include Fujifilm, Imation, Maxell, Memorex, Panasonic (Matsushita Electric), Ricoh, Sony, TDK, Toshiba, and Verbatim.
Ecma is a nonprofit industry association of technology developers, vendors and users. Since 1961, Ecma has developed standards for Information and Communication Technology (ICT) and Consumer Electronics (CE).
"Under the OSTA organization, we brought together various independent groups that were working on similar ideas to reach a consensus on test methodology. Now we are partnering with Ecma to leverage their expertise in the creation of broadly adopted international standards," says Chris Smith, chairman of the OSTA ODAT Committee, and general manager of the Sony Data Media Business Development Center in Boulder, Colo.
"The anticipated end result is increased user awareness of archival quality of optical media as a critical purchase parameter," explains Smith. "This will enhance customers' ability to make informed purchases appropriate to their application needs by providing a standardized evaluation result indicator. This product differentiation is intended to eliminate any guesswork that takes place when deciding which media to use when long life of data is a desirable attribute."
"From consumers who want to protect treasured photos and important school, business or tax records, to commercial users who must comply with an increasing array of regulations requiring archiving correspondence, e-mail and financial records, we believe there is a demand for a reliable optical disc archive standard rated for a longer life for storing important files on CDs and DVDs," says David Bunzel, president of the Optical Storage Technology Association.
CDs are made of several layers of different materials (see illustration below). In the early days of CDs, delamination was a problem - the separation of the layers--leading to CD "rot"--the oxidization of the reflective layer--in turn leading to data degradation.
"CD and CD-R rot was a true problem that manufacturers have convinced me has gone away," says Kubara. But, we "don't know that for a fact," he adds, noting he can't find information on what materials manufacturers are using to make their CDs.
The quality of both the reflective layer and the recording or dye layer determines how long the CD will remain readable.
It's all about gold
What's best? CDs made with a gold reflective layer are claimed to have a lifespan in excess of 100 years (assuming proper handling - see sidebar on next page).
Early this year, KMP Media LLC (www .kmpmedia.com), Rochester, N.Y., worldwide distributor of Kodak Media Products, announced the Kodak Preservation CD-R and DVD-R. Using a 24-karat gold reflective layer, the Preservation CD-R "can safely store digital data for up to 300 years," says the company, and the Preservation DVD-R for 80 to 100 years.
"The standard silver CD-R on the market today has a typical life span of 2 years to 15 years, while the standard silver DVD has an even shorter effective life," says Steve Mizelle, president of KMP Media, at the time of the announcement.
"The silver reflective layer eventually tarnishes through exposure to light, oxygen, heat, humidity, and rough handling. For consumers, the result may be the loss of precious memories, such as wedding and family photos."
KMP Media claims the 24-karat gold reflective layer on its discs will not tarnish or oxidize. Aiding the longevity is a proprietary phthalocyanine dye, which is the primary data storage layer. The substrate of the CD-R is optical grade polycarbonate, which KMP Media claims is better than many CDs on the market.
Delkin Devices Inc. (www.delkin.com), Poway, Calif., points to its Archival Gold CDs, with Scratch Armor coating, as the ultimate in storage technology. The Scratch Armor protective layer prevents scratches, scuffs, dirt, chemicals, and fingerprints, says Delkin.
CD burners create pits in the dye layer when it burns a CD-R; the pits are the digital information. Phthalocyanine dye reacts quicker to the writing laser than dyes found in most CD-Rs on the market, Delkin notes, thus making sharper pit edges and making the CD-R easier to read by CD drives. Compared to cyanine and azo dyes found in the majority of CD-Rs on the market, the company continues, phthalocyanine dye lasts significantly longer when subjected to the harmful effects of UV light, heat, and humidity.
The gold in the reflective layer prevents oxidation, one of the most common causes of CD-R failure. The combination of phthalocyanine dye and gold delivers a lifespan claimed by Delkin at 300 years, using the accelerated aging process of the U.S.-based National Institute of Standards and Technology (N.I.S.T.) to test the longevity of CD-R media.
A study published in the September-October 2004 issue of the N.I.S.T. journal, "Stability Comparison of Recordable Optical Discs--A Study of Error Rates in Harsh Conditions," came to some interesting conclusions. The study notes several factors that may contribute to the stability of CD-R and DVD-R media, with dye type generally considered one of the more important ones.
"Based on the test results for CD-R media, this expectation appears to hold true," says the study. "Samples containing phthalocyanine performed better than other dye types. In particular, phthalocyanine combined with a gold-silver alloy as a reflective layer, was consistently more stable than all other types of CD-R media."
The study also states discs using azo dye as the data layer "had less stability in light exposure and temperature/humidity stress testing. Media using cyanine dye performed well when exposed to light, but had problems under temperature/humidity stress conditions."
Further noting information is less accessible regarding the dye type used in DVD recordable media, the study says it is believed DVD-R media use a modified form of stabilized cyanine dye for the recording layer. As in the case of the CD recordable media, "the variation of stability among different brands of DVD recordable media is considerable."
Keep discs out of the light. "Depending on the media type and intensity of the light, a disc may fail due to exposure to direct sunlight in as little as a few weeks. This will be especially true when coupled with the heating effect of exposure to sunlight or combined with any other heat source."
The stability study found "the dye layer is probably the most significant layer for media stability. Other layers, such as the polycarbonate layer, may also degrade, but at a slower rate than the dye layer. Furthermore, a disc with a faded or damaged polycarbonate layer may still have all the data intact and, therefore, the data may be recovered and migrated to new media. If, however, the dye layer becomes damaged or has degraded, causing uncorrectable errors to occur, the uncorrectable data cannot be recovered."
The conclusions of the study point out "CD-R and DVD-R media can be very stable," noting some of the test results. "Results suggest these media types will ensure data is available for several tens of years and, therefore, may be suitable for archival uses. Unfortunately, it is very difficult for customers to identify these more stable media."
Given statements by some disc manufacturers that products using gold as the reflective layer are more stable, will the extra cost of each disc be a deterrent to their use? Are consumers going to balk at spending more money?
No, says Duke Doudna, marketing specialist for Delkin.
"It's easy to get customers to pay extra for Archival Gold discs. The general populace is getting the word that cheap CDs aren't always very good. I think most people know this intuitively. Even people who are not knowledgeable about how CDs and DVDs are made understand gold is extremely durable and expensive. Gold resists heat and corrosion much better than anything else.
"It doesn't take a big technical sales pitch. People want their precious images on the best media available, and they're willing to pay extra when they understand they're getting value for their dollar."
Doudna says dealers and photographers "are educating their customers by offering digital copies of images stored on Archival Gold. This creates an image of quality. Customers feel assured they're doing business with a professional who can offer products not available in the big box stores."
"Certainly, the manufacturers of the bargain-basement variety of low-priced CDs aren't saying how long their CDs will last," notes Kubara.
Other digital storage
CDs and DVDs have been adopted by many as "safe" backup media for their digital images. But we know just as many, if not more, continue to use their computer hard drive as their primary media storage.
In the 2005 annual consumer survey by PMA Marketing Research, consumers were asked how they stored their digital images. Seventy percent of digital camera owners said they kept them on their computer hard drive, 50 percent burned them to a CD, 40 percent kept them on their camera memory card, while 34 percent of digital camera owners also cited prints as their storage method (respondents were able to choose multiple methods), according to PMA Marketing Research.
You know hard drives fail. Everyone either has experienced it, or has known someone who has suffered through it. A hard drive is an electro-mechanical device. Parts wear out.
Some suggest you check out a hard drive manufacturer's statement about MTBF--mean time between failures--to determine how long a hard drive will last. MTBF numbers can be misinterpreted. A better idea is to check out the hard drive manufacturer's warranty; it's conservative, and you'll probably get more from the drive, but at least it's a good indication of lifespan. Generally, the warranty period is no more than 1 year or 2 years, with a small number of drives offering slightly higher warranty periods. This indicates storage of images on hard drives is not a long-term solution.
Interestingly, Iomega Corp. (www .iomega.com), Roy, Utah, which has a long history of data storage solutions, has another idea for consumers and businesses. Todd Schuelke of Iomega notes the huge growth in digital content, and suggests the Iomega 35GB or 70GB REV disc drive, with its removable discs. Iomega claims a 30-year shelf life for each disc, which has a price tag of about $60.
Everyone with a digital camera has a flash memory card of some type and size. Some consumers will buy a handful of them to swap out before turning to the conventional wisdom solution of downloading them to a PC. But what's to say the cards themselves can't be used as a long-term storage solution? Flash memory apparently is about to make its way into PCs as a replacement for the hard drive.
But long-term storage of images on flash memory cards? Mike Wong of SanDisk Corp. (www.sandisk.com) notes that flash memory has no moving parts, and it's a stable medium, "therefore there's no reason why not. It's ideal; it doesn't wear out."
There is the cost. True, notes Wong. Flash memory typically is too expensive to use as storage when compared to CD ... but what if there was a low-priced card?
That would then make sense, he suggests, alluding to efforts by SanDisk to create such a thing. The company is aiming such media at the food and drug channels, geared toward the point-and-shoot crowd, says Wong.
"If the cost was low enough, consumers might consider taking their pictures and leaving them on the card--the equivalent of digital negs."
The target price is the same as the price of a roll of film.
SanDisk, headquartered in Milpitas, Calif., is working on new technologies to bring the price down, says Wong, suggesting we should see something in less than a year.
Not so fast, says Imation Corp. (www .iomega.com), Oakdale, Minn. USB flash drives make more sense. While cards and USB drives use the same solid-state technology, "Flash Memory Cards are device dependent, and cannot be used for portable external storage," says the company in a white paper titled "USB Flash Drives: How they stack up against other storage options."
Still and all, just how long will the data--the digital pictures--be accessible on either flash memory cards or USB drives? Assuming our consumer doesn't stand out in the middle of a field during a lightning storm, clutching a handful of cards or USB drives, and doesn't store the media next to a powerful electric motor ... indefinitely, especially if data is only written to the device infrequently.
What can threaten access to the data is wear on either device's contacts. The contacts are gold, which, as noted above with gold CDs, doesn't oxidize (rust), but that gold can be worn down with repetitive device inserts and removals.
What's more likely to affect the lifespan of the images stored on any of the digital media mentioned above is the longevity of the technology using it. How many computers now come without floppy drives? How long before CDs are a thing of the past? DVDs are now being replaced by dual-layer DVDs. True, there's no obvious replacement for flash memory currently on the horizon, but humanity does have a habit of introducing new technologies at the drop of a hat.
So, ultimately, finding a long-term digital storage medium for picture files--say 25 to 50 years--is a fool's errand, a wild goose chase, because storage technology will change (perhaps several times) between now and then, leaving whatever medium we choose today obsolete long before its expiration date. The choice of digital storage medium perhaps should be based on security in the short-term--say 10 years ... or less--with the assumption, as time rolls on, we'll need to change media frequently.
Proper CD/DVD handling
1. Handle discs by the outer edge or the center hole.
2. Use a nonsolvent-based felt-tip permanent marker to mark the label side of the disc.
3. Keep dirt or other foreign matter from the disc.
4. Store discs upright (book style) in plastic cases specified for CDs and DVDs.
5. Return discs to storage cases immediately after use.
6. Leave discs in their packaging (or cases) to minimize the effects of environmental changes.
7. Open a recordable disc package only when you are ready to record data on that disc.
8. Store discs in a cool, dry, dark environment in which the air is clean.
9. Remove dirt, foreign material, fingerprints, smudges, and liquids by wiping with a clean cotton fabric in a straight line from the center of the disc toward the outer edge.
10. Use CD/DVD-cleaning detergent, isopropyl alcohol, or methanol to remove stubborn dirt or material.
11. Check the disc surface before recording.
1. Touch the surface of the disc.
2. Bend the disc.
3. Use adhesive labels.
4. Store discs horizontally for a long time (years).
5. Open a recordable optical disc package if you are not ready to record.
6. Expose discs to extreme heat or high humidity.
7. Expose discs to extremely rapid temperature or humidity changes.
8. Expose recordable discs to prolonged sunlight or other sources of ultraviolet light.
9. Write or mark in the data area of the disc (the area the laser "reads").
10. Clean by wiping in a direction going around the disc.
For CDs, especially do not:
1. Scratch the label side of the disc.
2. Use a pen, pencil, or fine-tip marker to write on the disc.
3. Write on the disc with markers that contain solvents.
4. Try to peel off or reposition a label.
-- National Institute of Standards and Technology, Publication 500-252: "Care and Handling of CDs and DVDs A Guide for Librarians and Archivists."
Deciphering the dye layer
Phthalocyanine dye is more responsive to the writing laser; cleaner, better-defined pits are created, resulting in fewer errors when burning data to the CD. This dye has the longest lifetime of any photosensitive dye. It also is more transparent, for a high reflectivity, resulting in better compatibility among readers.
Phthalocyanine naturally resists the harmful effects of UV light; cyanine and metal azo dyes are very reactive to UV light. The stability of phthalocyanine dye makes it more resistant to damage from heat sources.
Discs with a cyanine dye reflective layer have a shorter lifespan than discs using phthalocyanine-based dye. As well, the quality is variable. Given the dye color, light reflection is lower, producing less accurate burning.
Metal azo dye is less stable than phthalocyanine, has a higher error rate incidence when recording, and has a shorter lifespan. CD-Rs made with metal azo dye usually are blue and use a silver reflective layer.
|Printer friendly Cite/link Email Feedback|
|Comment:||Facts of life: there are many ways to store your photos on digital media.|
|Publication:||PMA Magazine - Connecting the Imaging Communities|
|Date:||Oct 1, 2006|
|Previous Article:||PMA data watch: higher capacity memory cards do not discourage printing.|
|Next Article:||Instant information: digital signage company GFX Dynamics uses RFID and other technology to provide info on any product a customer touches.|