Dear George … or, “How I learned To Love GMT, One More Time.”

Fisherman On The Andaman Ocean

Fisherman on the Andaman Ocean

Photographs © George A. Jardine

Yesterday I was presenting Lightroom at the APA Workshop for assistants here in town, and we had a pretty lively discussion about date stamps, time zones, and filenames. If you’ve read some of my previous postings on filenames or on time stamps, you already know that I have some pretty strange ideas on the subject.

As time has passed, I’ve become more convinced than ever that the one, natural, already-existing, best, all-around sequence number in the universe is already there right in front of us. Why invent a new sequence number, when the actual moment a photograph was taken is an easy to access, and perfectly valid universal sequence number?

Collections of photos assembled to tell a story have their own logical sequence. Which is obvious, and needs to be preserved so that the collection can tell its story. That’s why we have collections. But collections aside, no matter how I choose to search or view the photos in my library, by text search, by keyword, by folder, or whatever, I always—and I do mean always—want to see the results of that search in chronological order. A text or keyword search is a way to narrow down a library into a manageable chunk, and after that your search becomes visual. In a visual search, shoot chronology gives a meaningful context to the results. And my file naming gives me that context—both in the catalog, and in the file system.

That… in the file system part of the criteria is important for legacy and archival reasons that many photographers don’t get when they ask ‘Why not just sort by capture time, in the catalog?’

So, I have a bunch of reasons why the actual time stamp is the basis for the filename sequencing in my photo library. The only fly in the ointment is if you’re shooting, while actually crossing time zones.

When I returned home after the workshop, I found this in my mailbox:

Dear George,
What do you do with the capture time when you cross ‘backwards’ in time to a new zone. If the time on the camera is changed to the new time zone and the files are named using the capture time they will not appear in the sequence in which they were taken on that day. For example, we travel from Australia to Hawaii every year for holidays. When we go there we cross the International Date Line and arrive there at an earlier time on the same day that we left Australia. Obviously if the date in the camera is changed to US Pacific time, the early photos taken on arrival in Honolulu will sort ahead of those taken just before we left Sydney.

Do you have a technique for dealing with this?

Since I made my New Year’s Resolution last year to always keep my cameras set to GMT, that’s what I’ve been doing, and it seems to be working out pretty well so far. (I haven’t lost weight, but at least I’ve been sticking to that one resolution.) Admittedly, I also have not been traveling as much either, so that one resolution probably hasn’t been tested well enough in the long term to prove bomb-proof. And that little thing about ‘what happens when you cross time zones while shooting’… has been in the back of my mind too, but so far, it hasn’t came back to bite me in the butt.

Long story short, this e-mail question from a customer caused me to start thinking a bit harder about the problem, and I began writing back a long thing about how ‘what you really want is something that sorts by YOUR internal time clock… not the local time!’… or some crap like that—essentially dodging the question. It’s when I got to there… that I realized he was right! What’s needed truly is a way to sort by the actual moment the photos were taken.

Why not encode GMT into the filenames rather than the “corrected”, local time. So the solution turned out to be pretty easy. It’s back to GMT again.

Weighing A Valuable Idea

When I made my New Year’s Resolution, I started keeping all my cameras set to GMT. When I get home from a shoot I first adjust the time stamp to the local time, and then create the new filenames using the adjusted time stamp.

That process gave me filenames that look like this:


(I also encode the time zone abbreviation into the filenames, because without that, the actual time stamp is meaningless… something I wish the EXIF committee would wake up to. The original filename is also appended to the new filename for legacy reasons, and… to give me an accurate sorting sequence when I’m shooting more than one frame-per-second with a motor drive.)

The solution is to create the filenames using the GMT time stamp, and only after that change the time stamps in the catalog. This workflow gives me the best of both worlds: a filename that sorts chronologically no matter how or where I view it—just as before—and… a time stamp in EXIF that allows me to view and sort by that, if I need to (at least within the catalog…).

This process gives me filenames that look like this:


Which is exactly the same, only with the 6 hour difference between GMT and MDT added back in. If I need to see a time stamp reflecting local time, I look at the Info Overlay or the EXIF anyway. This filename only serves as a sorting mechanism, so it’s all the same. And next time I cross a time zone shooting pictures, they will still sort “chronologically”, at least according to my clock. 🙂

So thanks to Geoff for sending in that question. It’s that kind of carefully thought out and crafted question that sometimes causes me to rethink things, and maybe even come up with a better solution for a problem. And in the end, they’re also the ones that show me which customers out there are truly paying attention, and make it all worth while.

Posted in Essays, Thoughts & Photos.