What happens when you apply this filter vertically , is that the image is copied, the copy is rotated 180 deg, thinly slashed and then combined with the original image. The same will happen if you choose Horizontal but from a horizontal perspective. You can also combine it so it will do both . Emboss Stamps or carves out a three-dimensional look to your image. Emboss only works for RGB images.
Depth determines the embossed carve depth.
The Azimuth slide determines light direction, but so does Elevation . Think of Azimuth as a shining satellite, moving around your image - the light in the image will change as it moves. Think of the sun when it reaches zenith. There will be no shadow. When the sun falls or rises, the shadows will get longer or shorter, and the direction of the shadows will also change.