python export 16 bit tiff
>>> import skimage.io
>>> im = skimage.io.imread('a.tif', plugin='tifffile')
>>> im.dtype
dtype('uint16')
>>> im.shape
(288, 384, 3)
>>> im = skimage.io.imread('a.tif', plugin='freeimage')
>>> im.dtype
dtype('uint16')
>>> im.shape
(288, 384, 3)