Gray days can make for gloomy colored photos. But they make for fantastic Black and Whites. The cloud-diffused light means no shadows that will obscure details when converted to B&W. The gray sky can be lightened to white, providing a stark backdrop against which stuff really stands out. B&W works best when subjects are wearing black or white, for maximum contrast. Other shades will disappear into gray tones, like the grass.
Why the black border? Hmm. While I like the expanse of white sky, I didn't want the white-ness to overwhelm. The black border only works because there is heavy black within the picture too; otherwise it would be overwhelming. Also, I thought the contrast between the clean, graphic, black frame and the messiness of the family candids balanced each other out. And, it draws attention to the white negative space created by the black shapes.
Why such a thick border? It makes me think of postcards, or posters (strange that I think of both, since the scale is so different). Actually, none of this reasoning happened when I added the border. I just thought it looked interesting, and came up with reasons for this blog post.