This colorization was built using a series of layer masks. Some parts of the image, such as the skin tones, are comprised of numerous masks. In this case, the skin was colored using a half dozen layers of differing colors, shadows, and highlights. One thing that I didn’t do is fine tune the contrast before I began. If I had, certain areas such as the fence posts on the right-hand side of the photo would have shown better texturing. Additionally, I might not have failed miserably on the ivy in the background (and by “failed miserably” I mean “I gave up”).