Last week I got an e-mail from a reader that pointed at a serious problem he had. It seems to me more important to take this up in a column and push back the RAW column another week. This could save some people from serious grief.
Reader: Hi. I wonder if you have knowledge about corrupted photo files, why they occur, how to avoid and how to cure them. I am dealing with seemingly random corruption. Sometimes the files are a mess; sometimes a thumbnail appears but the file will not open. The programs that are advertised to deal with this problem get mixed—usually rotten—reviews.
Me: Dear Reader, If you're seeing lots of corrupted photo files (like more than one or two in your entire collection), that's evidence that there's something wrong with your computer system. If you have multiple hard drives, especially if they're on different data buses, and the corrupted files seem to be predominantly on one drive/data bus or another, that's a sign of trouble on that storage path.
It could be as simple as an inappropriate or slightly defective cable. Back in the old IDE/ATA days, I decided to replace the rats' nest of ribbon cables in my PC with more modern and orderly bundled types, and I ran into all sorts of corruption problems. The bundled cables had higher impedances and the driver circuitry on the motherboard simply wasn't up to pushing the data through the higher-impedance cables. "Better" in that case proved to be worse.
File corruption could also be evidence of an unreliable hard drive.
Another place to look for evidence of data path problems is in your backups. If you have a way of running verification or checksum passes on backups, enable that and see what you get. If the backup software reports back with occasional problems validating a backup, that says you have a problem. A corrupted backup is a much bigger problem that a corrupted photo file. You'd be surprised how many people get bit by this one because they just assume the backups are good, and then, when they need them....
There are also test utilities out there, either cheap or free, which will heavily exercise data paths and hard drives to try to find errors. Something you set up and let run overnight or even for a couple of days, while it shuffles terabytes back and forth, and then you look at the report. Can't recommend a specific product, but Google will be your friend in this area.
No, I don't know of any good repair programs. The best scheme is to just have a whole bunch of image processing programs, both high-end and low-end, that can read a whole bunch of file types and will tolerate screwed up files. The freeware ones are frequently better at this than the expensive ones; Photoshop is particularly fussy about file quality. It will often tell you that it cannot open a file at all that another program will open and find only a few bad pixels or one bad row in.
Reader: Ctein, thanks for this extensive comment. I am experiencing backup issues. Will check as you suggest. I begin to think that cloud storage is superior to multiple externals. Again, thanks. Much appreciated help.
Me: Dear Reader, Then you need to get on this sooner rather than later. The corruption isn't necessarily happening in a data path that can affect files that your system writes to and uses. But, if it is, eventually your OS will start misbehaving and possibly become entirely unbootable, and you will not have a trustworthy backup that you can restore it from.
I don't know what kind of system you have or your level of computer expertise, so I'll make these very general remarks. First, get one of those drive-exercising utilities so you can test as you go along. Next, decide if you're interested in figuring out exactly what is wrong or just fixing the problem.
If the former, you need to make a systematic changes to your hardware and run tests after each one, until you isolate the bad actor. Try replacing the drive cable, try using the drive on a different I/O port, try using a different drive, etc.
If you just want to fix the problem, the best way is to buy an external hard drive as different in every way from your current one as is possible. Buy it from a different manufacturer and use it with a different interface, assuming that your computer has more than one external interface. For example, if your current drive is a Seagate USB (Seagate drives, in my experience, are not reliable) get a different manufacturer's FireWire or eSATA drive (assuming you can support either of those). That should make your problems go away entirely. If you don't have a choice of interfaces, don't make yourself crazy; the most likely point of failure for external drives is the drive or cable, not the interface. Remember to buy a new cable to go with whatever drive you get.
You need to deal with this now. Cloud storage backup isn't going to fix anything that's wrong with your system.
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That's it for this time. Next week should be the long-awaited RAW column, unless another fire turns up that needs putting out.
CteinCtein (it's pronounced "kuh-TINE," and yes, it's his only name) ferrets out bad busses on Wednesdays on TOP.
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A book of interest today:
(To see all the comments, click on the "Comments" link below.)
Featured Comments from:
robert e: "You and your reader probably looked into this already, but sometimes an unseated cable connector can cause intermittent file corruption and other disk problems. I've seen it happen (though that was in the old days of wide ribbon cables). A connector that was marginally seated (perhaps at the factory, or during an upgrade) could work fine for weeks or years before it worked loose to the point where problems happen. Connectors have improved, but you never know.
"So if you start having weird file problems, check all the cable connections you can get at comfortably. Really.
"If you're uncomfortable opening electronics in boxes, then it's good enough to narrow down the problem to a particular box or cable.
"But if your computer is a box that sits on the floor or a desk, it probably needs periodic cleaning inside anyway, whether it's done by you or a tech (whoever it is should know what they're doing). The last step to cleaning it out should be to check the cables and connections. Pay attention to fans, too. Dust buildup can make them vibrate, among other bad effects, which only helps connectors work loose.
"External drives, too, can have cabling inside, and sometimes fans, and dust. Even laptop drives often depend on cable connections—these are usually accessible through a hatch."
David Dyer-Bennet: "I've been scanning 1960s photos since mid August, and let me tell you, the bit rot is terrible. Neither I nor the other photographer whose work I was scanning appear to have had water filters in our darkroom, and commercial processing wasn't any better. And, now, there are layers of scratches on top of all that. I've spent over an hour spotting out crap on a few of the shots (ones I have some plans for and think are worth the effort; it's essentially a restoration job even though I have the original negatives for my own work). As a general rule, I advise against inventing organization and storage schemes for negatives if you haven't had any experience in darkroom work. (But, you'll notice, I still have the negatives from snapshots I took in second grade, which puts me ahead of most people.)"