When I try rendering a few of my textured objects I am getting some black artifacts in the render. I've tried fooling with the settings (fooling being the operative word, as I am a rendering dunce) and I managed to get rid of it by using the mitchell-netravali filter and turning up 'ringing' up to 1.0 (using max 9.) I have no idea what it does.



So here's a picture of the problem. Can someone explain what's going on and any other way to fix it. It would be appreciated.

(forgot to add the picture, please delete the other one.)