On the left you see my texture in photoshop, high passed and even with the contrast lowered -50 twice I think. On the right you see the texture imported into CE3 and painted onto some terrain. Its actually from the map that comes with the engine, all I did was replace the texture of one of the materials that was already…
For your contrast problem, use the DetailTextureStrength slider. 1 is often too much depending on your texture. Try to avoid textures that have very different color ranges, and try to put that color variation into the background texture.