The same Lego spacecraft, edited with Gimp according to Zoe Piel’s tutorial, so as to add texture. The paper texture is added as a mask so that the texture affects the pigment, whereas if you simply add the texture as a multiplying layer on top of the rest, it shows throughout the picture, whites and colors alike.
As a goodie, here is a high-resolution (2048px) paper texture for free download (Canson paper shot with my Canon EOS 350D against the window pane for transparency). Use high-resolution textures (instead of the small textures available as default in Photoshop or Gimp) to avoid ’tiling’ artefacts which become atrocious when the image is downsampled. Find more textures with Google images.