I painted a section of Aegis Defence Lines for Warhammer 40k a while ago, keeping it simple. Codex grey and dull steel are my colours of choice for the Imperial Guard, reflecting the mass-produced origin of their gear and more generally the harsh and joyless existence of a common soldier in the forces of the Imperium.
While each battle-hardened man-at-arms might just be a small cog in a monstrous machine, they are nevertheless the closest to ‘you and me’ as one is going to find on the battlefields of the 41st millennium. So it seemed fitting to revisit the Aegis Defence Lines and add some personal touches, showing that these barricades are literally a matter of life and death for a guardsman if he finds himself fielded on some Emperor-forsaken outpost facing off against ravening hordes of aliens or frothing lunatic traitors.
I’ve coloured in some functional buttons (in appropriate emergency red for the most part, because pretty much everything happening around an Aegis Defence Line is going to be an emergency) and added a purity seal to one section, which the regimental priest attached in a solemn Ceremony of Protection before the impending battle.
Finally one of the soldiers has inscribed his own expression of faith in the almighty Emperor in white chalk in the face of the oncoming enemy.