When I first saw this pin I thought, "Cool!" for about three seconds, and then my logic kicked in. How could the skins be uniformly another color? And how does each individual piece of pulp get colored, but nothing happens to the white parts?
We had to try it.
So we got out some dark red food coloring and injected as much as we could. As you can see below, most of the ink settled to the bottom of the lemon, making it look sadly bruised. We tried at least three different places to make sure we got as much as possible in, but it also kept leaking out the other holes.
We let the lemon sit for awhile to make sure we gave it a change to spread and soak in. Then we cut it open, and below is the result. As I suspected, you shouldn't believe everything you see on Pinterest.