As a skeptical consumer, you’ve probably looked at photos in the news or a piece of advertising and thought, “Hey, I bet that was faked, because no cat/person/burger is that perfect.” Now with a little help from Photoshop, and Tim Mathenson’s tutorial [NOTE: Looks like the page linked here has been changed or removed since this story was posted in 2007, but the steps remain below], you can tell.
• Open Photoshop
• Open questionable image
• Press CTRL+U or go to Image -> Adjustments -> Hue/Saturation
• Set Hue to low
• Set Saturation to high
• Scroll the light bar back and forth, looking for areas of the image that don’t match
• If you find a splotch of discoloration, that may indicate the picture was retouched.
Tim says this will work on any retouched photo, not just Photoshopped ones. — BEN POPKEN