The exports are / should be gray scale.
Not on my computer, that is where I got the original post from. When you export water to bitmap and check properties it even says 256 color .bmp. The elev.bmp, which is a grayscale, will show as 8-bit grayscale when you right-click and check properties.
I work/save/edit using these colors and everything is working wonderfully. If I import this and then export it back out I would get the same image.
Strip