There's a little airbrushing here and there, but for the most part it's all hand done with model railway weathering powders. A medium gray, dark grey, and black. Takes FOREVER! but it works well. The front had three passes and the rear one, with some secondary work on the 'mechanical' parts. Most don't notice but in ALIEN the rear is completely white with no weathering as it was under the cover. I did that first, and then gave the whole thing another pass so it's more as seen in ALIENS. Just looks too clean without it.