This work by Cayetano “Tano” Ferrer is two years old (here’s some more recent stuff), but it’s been making the internet-rounds again because of similar effects used in new Amnesty International Ads (the tagline on those posters translates to “It’s not happening here but it’s happening now”).

To be clear what’s going on in both of these cases, a photo is taken of the background, photoshopped with the sign/person, and then the sign pasted over/a poster mounted. So you do have to stand in the exact right place to get the maximum ‘transparency’ effect. But impressive none-the-less.

(via Boing Boing)