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For for my job doing environmental consulting, legal liability is a forethought with every product we put out. I have a project right now that requires photo documentation of a construction site. Our new Canon point-and-shoot cameras apparently do not allow you to put a date stamp on the photo, which is how we have typically done things in order to "prove" when a photo was taken.

However, my boss, a self-admitted technophobe, does not understand the benefits of the EXIF data nor the lack of credibility of date stamps. I have on rare occasions had to Photoshop out the date stamp and replace it with a different date because the camera's time was set on the wrong 12 hour time. So I have tried to explain how easy it is to change the date on the photo, but that the EXIF data stays with the photo even if it is manipulated. If a regulatory agency doubted the authenticity of our photos, I figured that we could just send them the original photo and they can look at the EXIF data.

So my question to you is, how easy is it to change the EXIF data? I personally have no idea how to do that, and I suspect that many other people who know less about photo editing would be as equally clueless. I am going to assume that the EXIF info is not as credible as I think it is, but would you agree that it is more credible than a date stamp?
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Virginia Herping
http://groups.yahoo.com/group/VaHS
Virginia Herpetological Society online store
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"The irrational fear of snakes is the only excuse a grown man has... to act like a complete sissy" - Colchicine

So my question to you is, how easy is it to change the EXIF data? I personally have no idea how to do that, and I suspect that many other people who know less about photo editing would be as equally clueless. I am going to assume that the EXIF info is not as credible as I think it is, but would you agree that it is more credible than a date stamp?

I actually don't know how credible a date stamp on a photo is in this day of digital manipulation. It would be easy to fake a date stamp on a photograph in photoshop. You couldn't do the negative, but the print would be easy.

There are a variety of EXIF editors and you can actually edit some parts of the EXIF in photoshop as well. It is basically just a file of data attached to the photo and can be manipulated without too much trouble by anyone who really wanted to make the effort. I don't know how well it would hold up legally as proof of the time/date of the photo.

And, of course, it can be easily faked without editing by simply setting the camera's date and time to the desired values and then taking the picture.
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Chris Harrison
San Antonio, Texas

Thanks Chris, I was hoping you'd chime in on this one.

The bottom line is that none of it is fully credible. I was able to fake a date stamp by removing it in PS, and then using MS Word, of all things, to mimic the text of the Kodak cameras we were using. The photos were used side by side of other photos with the Kodak date stamp straight out the camera. Nobody caught it! So you brought up a good point that even the camera has no legally defendable way of provided the correct date and time.

Photo editors are ubiquitous, but I know a lot of photography enthusiasts that knowing nothing of the existence of Exif data, much less how to manipulate it. So no matter what is done, none of it credible.
THANKS
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Virginia Herping
http://groups.yahoo.com/group/VaHS
Virginia Herpetological Society online store
http://www.cafepress.com/vaherpsociety

"The irrational fear of snakes is the only excuse a grown man has... to act like a complete sissy" - Colchicine

>>So no matter what is done, none of it credible.

I would say that's pretty accurate. I would not consider either to hold much weight. A sworn affidavit saying they were accurate might work for most legal purposes. Remember, film photos were used as legal proof of all kinds of things without any date stamp.

If anything, I would think the on-photo date stamp should mean just a little more simply because if it's changed later and not exactly right it would be possibly for a tech to prove that it was not created by the camera (what you did in photoshop COULD be detected). Any 12-year-old hacker with a binary editor could change the EXIF data and there would be absolutely no trace of it being changed. With most cameras, you could even edit the photo and put it back on the camera (I can't be sure that that is not detectable, but I doubt it).
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What goes up must come down...unless it exceeds escape velocity.

I agree with what has been posted so far, but I thought I would add that this technology is evolving and apparently there are ways to corroborate EXIF data and time stamps (probably on an individual basis) as well detect alteration. In these scenarios if a photograph along with EXIF is entered into court as evidence, it could then be used to corroborate other pieces of evidence or create reasonable doubt.

Probably no one would be convicted or absolved on a photo w/ EXIF data alone. Chris and I saw a great example posted right here on these forums. There was a photo posted with EXIF intact. By itself the photo was no big deal. But the information provided by the poster along with the posted photograph painted a very different picture. Just something to watch out for.
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