Actually it looks like the person probably took the photo outside but in a bit of shade using a very low soft white spot light held off to one side. They also probably used some kind of filmy filter, likely cheese cloth or a very thin cotton cloth to greatly diffuse the light, and maybe a small hand held reflector below the baby to put some light on the face.
You could get a similar effect using some kind of a spotlight portrait filter in Photoshop on the lowest settings and buy messing with the shadow and highlights settings, but it wouldn't be quite as nice. If you are actually taking the pictures you're better off using that small spot, cloth, and the light filter below.
Baby skin is just lovely in the right light and I've never seen an artificial filter yet that could make it look better than doing it the old fashioned way.
A good way to get this soft effect is also to put the baby near a window that has very sheer white curtains and to open the curtains just enough to get good natural light for the shot and/or use a hand held light, soft white bulb, down and off to the right of the baby.
I'm no pro, yet, but I've taken my fair share of baby shots, for fun, family stuff mostly, and that's how I do it. With the window set up I've described.
What you are looking to do is to stay away from any kind of harsh outdoor back light. You want diffused soft white light preferably coming through curtains, or trees, or cloth. Baby skin is very luminous, often almost perfect. It doesn't take much to make it look gorgeous. It already is a lot of the time. |