Digital Light & Color

From what I can figure, when applying a mask to an image, the histogram of the image continues to represent the distribution of tones throughout the entire image. To better manipulate the tones in just a portion of the image, is there a way to have the histogram reflect only a portion of the image, based on the mask area? In other words, mask out the sky and do a tone curve just for the foreground etc. where the histogram only shows the distribution of the tones for the foreground.

Thanks

There is no direct way, but you could use the mask to make a version of the image where the unmasked area was, for example, black (one way is to use the Composite transformation with black as the overlay color and reversing the black and white Amount sliders). The histogram of the resulting image will have a spike at the left end (where black is represented), but the rest of the histogram will represent the non-black masked area. If the spike makes the rest of the histogram too small to see, try using the Medium or High Histogram Expansion options on the Curve.

Thanks. I will give that a try.