Andrew Kantor's Place: A scary zip file moment

A scary zip file moment

Published 5/16/05

I have a ton of photos of my son, almost all of them in electronic form. Further, I tend to save photos as TIFFs, not JPEGs (or at least in addition to JPEGS) because JPEGs use lossy compression, meaning that saving it that way loses some information. Usually it’s too subtle for human beings to notice, but if you re-save a JPEG too many times, eventually you will see the file degrade.

So TIFF it is. But TIFF files are much larger than JPEGs. And because I’m a Smart Guy and back up my photos regularly, I figured that I would use WinZip to compress those TIFFs without losing data, and thus fit more photos on each CD. Zip files being the standard compression format in the world, I figured I would always be able to re-open them.

So I created zip files, one zip for each month of photos — 2004-04, for example. And then I backed up those files to multiple places.

And then I needed those photos. And then I found that a bunch of those zip files were corrupt. Somehow, WinZip screwed up, and I couldn’t open them.

And all my backups were copies of those bad zip files. Oh-oh.

I got lucky. I found a backup CD that contained the originals, unzipped. And I quickly made copies of those files.

I don’t know, yet, if I shouldn’t trust zip files in general, or if this was a WinZip problem. But I won’t be zipping any of my files for backup anymore until I know the culprit. (Or I’ll at least test my backups immediately.)

The Fray

5 responses (add yours)

Dusty says:

Great article on archiving digital photos (USA Today, 5/20). You are following about the same route that I seem to be travelling and your research has helped me speed up the process. The panic I felt when I thought I had lost a disk of pictures was something I don’t want to go through again, even though I know I will for reasons which may not yet exist. I have you bookmarked. Thanks.

May 22nd, 2005 at 9:01 PM

Chuck Staples says:

I can sympathize with the panic of potentially losing original work that can’t be recreated. I’m not trying to sound like a jerk, but with the cost of media (CD or DVD) these days, why compress all of your photos when you archive? The savings (for JPEGs and RAW files) is negligable and the time spend encoding and decoding can be eliminated. Make the technological gap between you and the ACS even greater by picking up dual-layer DVD burner for short change.

May 23rd, 2005 at 12:53 PM

Andrew says:

Chuck: You’re absolutely right, which is why I’m not compressing backups anymore. The original reason was not to save money, but to save space — I was trying to avoid having so many disks.

Of course, by fitting more on each disk I increased the risk; losing one would mean losing a lot more files. So all in all a bad idea. Lesson learned.

May 23rd, 2005 at 12:56 PM

alan says:

ZipZag is an advanced archiver that handle over 180 extensions:
Windows/DOS Archives (Zip, 7z, Ace, Arc, Arg, Arj, Asd, Bel, Bza, Cab, Czip, Dz, Ear, Gca, Gza, Imp, Jak, Jam, Jar, Lha, Lzh, Lzs, Rar, Rez, Spl, Sqx, War, Yz1, Zac, Zoo)

http://www.yaodownload.com/utilites/file-compression/zipzag/

May 8th, 2006 at 11:48 PM

Leland says:

I don’t zip them. I burn twin CDs. One goes in a vault, the other is for use. The CDs are dated. Once they get to five years old I begin looking at copying the CDs again to avoid loss from CDs the foil in the CDs failing apart.

May 10th, 2006 at 11:20 AM