Jan 052008

This post isn’t about dating. I’m the last one to give advice on that topic. Instead this about what to do if you have a bunch of digital photos with the wrong date. This can be caused by forgetting to reset the clock when changing the batteries, or vacationing in a different time zone, or even scanning film photos.

Recently I ran into a folder of photos from a friend with the wrong date. The photos claimed to be shot in 2004, but I knew they were shot in 2006.

If it had been one photo, it would be easy to fix. Almost every graphic program I use or know of will allow you to access the EXIF data field in a photo file. This is were the shoot date is stored. But I had about 100 photos to change, and I like a challenge. I thought about writing a script (Action) in Photoshop but that would be too time consuming and I would like to offset the date, not just set all 100 photos to the same date and time.
I checked Irfanview and Xnview.
Irfanview could set the data one photo at a time.
Xnview could set all 100 photos but to the same date and time.

I have run into this before, so I had already tested a bunch of shareware programs. The answer is Exifer by friedemann-schmidt.com. It is a flexible tool for working with the data inside your jpg files. It can work with all the EXIF fields and IPTC fields. The best part is the price- free (he would like a postcard.)

The first thing I did was figure out how far off the date and time was. I happened to have a set of baptism photos shot with another camera. I was able to compare the dates and times. Because the date and time were so far off I couldn’t just do the math in my head. I made a simple Excel spreadsheet to calculate it.
I put the bad date in cell A1, the good date in cell B1, and this formula in cell C1:

In Exifer I click the ‘Change Directory’ icon and navigate to the folder of photos to change.
from the menu Edit:Select All to select all the files in the folder
from the menu EXIF/IPTC:Edit… to bring up the editing window
select the EXIF Data tab and then the Date tab

I need to add days to my photos so I keep the + sign (- subtracts days and time)
You either have to use the arrows or paste in the number of days, the control seems to have some trouble with just typing in the number of days you want except when less than 10 days.
The hours window may be confusing but just add your time to 12:00:00 AM (midnight). I needed to add 866 days so I cut it from Excel and pasted it to the days field. I needed an additional 4 hours and 3 minutes so I set the ‘clock’ to 4:03:00 AM.

Do NOT click the ‘Incremental’ button as this adds the date and time to each file so the first file would be right at +866 days but the next would be +1732 days and so forth. This might be handly if you wanted to add a set number of minutes and seconds to a set of images.
[Side note: either Excel or EXIFer has bad math. I had to run this procedure a second time to get the date right. It was off 14 days.]

I did click the ‘Apply to Date modified and Date digitized’ as I wanted to change the date that appears in Windows Explorer.

Click the Okay button at the bottom. Click the Confirmation window. Click No to back up the EXIF data. (If you’re unsure of what you’re doing you may wish to click ‘Yes’)

For some reason, the program doesn’t actually write this data to the file. So the next step finishes the project.*
from the menu Edit:rename/redate and copy
uncheck Rename
check Redate (by EXIF date fields)
click Okay and the Confirmation window.

Now, all your photos should have the right date and time. If you didn’t make any mistakes the entire process only takes a minute or so. A variation of this process can be use to write custom info to the other fields: Copyright, photographer, email links, whatever you have can probably find a home in the IPTC fields. [The EXIF fields tend to hold camera specific info.]

Exifer is a handy little program and I highly recommend it. It’s good for Professional photographer and even better for amateurs. (We’re more likely to make mistakes that need fixing.)


* This is a quick way to rename your photos using data in the EXIF and IPTC fields.

 Posted by at 2:58 pm

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