Above and below: I searched and looked at a lot of photos with worms showing their mouths and amazed how they looked so alien then I imagined they would, almost as if they weren't worms at all.
But I wanted my sand worm to be different as it would be monstrous by size so I thought that the mandibles won't work .
1. Taking the original sketch and working on a few colour schemes starting with the brownish colour for the armour. Kept the jaw but with sharper teeth, wanting to experiment on the colours to see how it goes with brown and grey together.
2. Going for the more grey and dark theme but for the underbelly would be more dark brown but would be difficult to be seen with the amount of shadow it would cast and sand in the way.
3. Decided to lift the head up much higher. Worked on the shades under the edges, not too dark as the edges and space between the plates not too deep. But for the mouth it would be very dark. I wanted the worm to bring it's head out at such a surprise with the sand burst out after it was tunnelling beneath the sands. Throwing the sand everywhere and then opening it's enormous jaws.
4. Given the sky a pale blue background with faint streams of thin clouds which can be rare in most desert regions, lowering the opacity of the brush to create dust clouds all around the head and not too thick.