First, if an image texture is not directly lit, either by sun or by a light, I get the default grey colour. Why? Second, I defined the Photoshop plugin folder as the plugin folder for Bryce 5. But I cannot use Photoshop's filters like texturizer or artistic or levels, only the filters that I installed separately, like Eye Candy and Almathera Lightning Maker. What did I do wrong?

I'm not sure about your first question. Photoshop's own filter's will only work with Photoshop (and Image Ready), they are not carbonized to be used by other programs, bryce included.

About the firts question... I think you should set the ambient property of the material related to the texture (like diffuse). Hope it helps

Vasquez, what do you mean "set the ambient property"? Put a value which is not zero? I think I tried something like that, but then I didn't get the image I wanted. It was ... diffused. :-) Or, better to say, the colours were washed out.

That's the same object with the same texture, the only changes I made in the two renders is indicated by the red arrow, you can also play with the darkness of the shadow on the object changing the ambience (green arrow). I hope I havw correctly understand your request. Cheers.

Yes, you can. Thanks. The result can be seen in my post "May Challenge part WIP", on the wheel of the plane. I put the image here, but then deleted it. The other post is a more appropriate place.