My idea with this shot was to use the same technique as I did with my Cherry Branch on White—using a group of Hellebores. In some respects these flowers are a tougher compositional target than the cherry branches—and you don’t have the immediate visual associations with cherry-blossom goodness to draw upon.
To make this photo first I cut the Hellebore stems from our garden. I placed them upright in a vase, and carefully arranged them against a light box placed vertically. Note that if I had shot against a normal white background (rather than the illumination of a light box) the background would have seemed a dull off-white or gray, rather than the striking white in the photo.
With the camera on a tripod and a macro lens in place, I shot a number of bracketing exposures, all biased to the right side on the histogram (overexposed). You’d expect a right-biased histogram with so much white in the photo, but I continued overexposing way past the normal range. I also did a little light painting as fill on the two larger blossoms.
In Photoshop, I combined the bracketed captures, starting with the lightest one as the background.