Photoshop - Colouring of a bug

Today we had an assignment in class to recreate a digital drawing of a bug by Arne Niklas Jansson. I had to recreate it step by step from flats to shadows to detail painting. The most interesting part of this work for me was the fact levels can be used to remove the initial sketch and to recolour the black outline to a nicer grey. The way the shading was done is something I would like to take and use in my own pieces. 

I would like to point out that I did not draw this. All I did was add colour and a hasty background.