Wednesday 18 April 2012

Me tampering with a photo

The original
I decided to tamper with one of my own photos tonight to see what it looks like after put through error level analysis - how clear is the tampering?

All I have done to the top photo is to compress it a bit - I compress all my photos because long upload times annoy me. But apart from that, there are no changes from when it came out of the camera.

Tampered cloud
I then used the lasso tool to copy a cloud, and I then played with the cloud to make it darker by adjusting the lightness. You can now see a light grey cloud above the big green tree. 

Error level analysis
I then ran this through FotoForensics - you can see that the cloud in question sticks out relatively strongly from the other clouds - including the one I copied it from. However, I didn't tamper with it much, so the error levels aren't that high (the whiter the pixels, the higher the error levels, which means more fiddling).

Have a look at these Fairfax photos and ponder how much they might have been fiddled with in order to produce the error levels that are evident.

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