I've been experimenting with doing a graphite drawing on one side of drafting film and then turning it over and working with coloured pencils on the reverse side.
I drew in the cat's eye and some of the surrounding fur making sure not to smudge the graphite.
Once I'd done a couple of inches of I turned the drafting film over and started working in coloured pencils.
Because the graphite is on the other side of the drafting film it doesn't smudge and muddy the colours.
One thing I need to keep in mind for next time is that I need to draw the graphite image in reverse so that when I turn the drafting film over I'm working the right way.
The final image is replacing the white backing board with a black one, a mid tone will work better but I can't find one at the moment.