I see what you mean. It looks like he used a desaturated background and added the figures with different lighting and maybe a little color for the foreground.

I separated the girl from the original b&w background and then used a couple of 50% grey layers with patterns in between the two to darken and de-emphasize the background. The background, as it was, was too distracting with too many people and even leaves growing out of the girl's head.  So, I toyed with the idea of using a typical studio background (digitally created). In the end I decided just to retain some of the original background, as a remembrance of the setting, but to update the portrait in time by using color and the frame effect. Hope she likes it. Not something everyone has.

 The next step will be to finalize colors (not fond of the yellow duck purse - maybe it should be white.) Maybe the dress should be a different color also, and that gap in the lower right tail of the dress should probably be filled in. Too much contrast in the facial features also.  The eyes are the soul of a portrait and these lack detail.  If the lady has another photo with better eyes, I could replace them and make her face come to life.  I've been known to discretely use eyes borrowed from someone else. See, it just never ends!

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears