What is the BMP format for Gray scale Images?

Question

What is the BMP format for Gray scale Images (especially for 16 bit per pixel) ? The wikipedia just talks about colour images for bmp.

Update:

Answer 1

As it appears, TIFF and PNG natively support 16 bit grayscale.

http://en.wikipedia.org/wiki/Grayscale

Im assuming that these images you wish to save are not simply for display but for some sort of post processing where you need the extra precision? If not, then I would suggest deleting the least significant 8 bits, and storing a simpler 8 bit bitmap with a color map to map each value to an RGB with a value -> (value, value, value) RGB mapping.