Over the years, new strains of Orcs appeared in the armies of Mordor. Morannon Orcs are just one of many breeds of Orcs. Stronger and more heavily armoured compared to normal Orcs, Morannon Orcs form the bulk of Sauron's army in the Battle of Osgiliath, the Siege of Gondor and the Battle of Pelennor Fields.
Here's how I painted and based them:
1) Using Green Stuff, make a tile pattern on the base of the model, leaving a small gap or two on each base.
2) When the Green Stuff has cured, undercoat it with Abaddon Black (Chaos Black).
3) Paint the tiles with Dawnstone (Codex Grey).
4) Apply Astrogranite to the gaps.
5) Drybrush the entire base with Administratum Grey (Fortress Grey)
6) Next, drybrush the base with White Scar (Skull White).
7) Finally, repaint the rim with Abaddon Black (Chaos Black).
1) After undercoating the model with Abaddon Black (Chaos Black), drybrush the armour, weapons and other metal parts with Leadbelcher (Boltgun Metal).
1) Basecoat with Doombull Brown (Dark Flesh).
2) Paint Khorne Red (Scab Red) over the top, leaving the Dark Flesh in the recesses.
Leather and Wood:
1) Paint the leather and wood with Rhinox Hide (Scorched Brown), leaving Abaddon Black showing in the recesses.
1) Paint the red eye with Wazdakka Red (Red Gore).
1) Basecoat the flesh with Balor Brown (Snakebite Leather).
1) Basecoat the flesh with Castellan Green (Catachan Green).
1) Basecoat the flesh with Dawnstone (Codex Grey).
1) Basecoat the flesh with Doombull Brown (Dark Flesh).