By Carlos Barria

I never imagined that a simple image on a piece of paper could have the power to transform someone’s suspicious look into an expression of surprise — the kind of surprise you might see on a child’s face as they watch their first magic trick.

But I saw this transformation a week ago, when I joined a group of journalists on a trip to North Korea. I brought a Polaroid camera along with the idea of taking a few portraits. I wanted to be able to offer these portraits to the subjects themselves.

I’ve always liked the idea of trading something with the subject of a photograph. I take his or her picture, or image, and in some circumstances, it seems appropriate to give something back. I can’t pay them, so ideally I send them a copy of the picture by email.

Knowing North Koreans have little access to the Internet, I brought a Polaroid camera instead. When I used it to take portrait pictures, I took two snaps. Then I gave one Polaroid to the person in the picture, and I kept the second for myself; one copy for them, one copy for me.

But, I didn’t count on the incredible expressions that would come over North Koreans’ faces as they watched the Polaroids slowly emerge.