Today however, resolution is much less of a problem, and color depth is one of our best and most attractive friends. We no longer have an excuse for churning out bland textures. Now that our palette is large, we need to use it. Of course I am not suggesting that cramming a scene with every color available is automatically a good thing. Rather, tonal variation within a texture, as well as the range covered by the whole of your texture set, should, where appropriate, make full use of the colors available.
Rock textures are some of the hardest to deal with.
The above examples hopefully give some indication of the variety of color information that can be contained within a rock texture, while still retaining a decent level of realism. Obviously in cases like this, the source image from which the texture is derived needs to be reasonably interesting, but it will usually be the hand-coloration that makes the difference. When applied with skill and moderation, vertex coloring can liven up the dullest areas, reducing the chances of producing a bland environment. The effect achieved through adding color values at vertices will naturally depend on the placement of the vertices, so obviously large-scale diffuse color changes will be all you can manage across large polygons. If you intend to rely heavily on vertex coloring, you'll get the best if your textures are designed specifically for this purpose.