[vtkusers] Saving images with greater than 8-bit depth

[James Geach]

Hi all -

I'm volume rendering using a fixed point volume mapper and a scalar to 
color table with up to 65536 colours, rendering to a virtual frame 
buffer (initialized with Xvfb and 16-bit depth).

I'm using window to image filter and then the standard PNG and TIFF 
image writers to save the frames, however these always seem to save as 
images with 8-bit depth.

Is there a straightforward method to write images using the full colour 
depth of the frame buffer?

Note - I am using VTK via python.

Thanks in advance for any help.

Jim