I've tried out the perforated aluminum, but all I got was a glass-looking texture.
Sounds like the repetition was too high, leading to sub-pixel features possibly. Try again after tweaking the geometry UVs; you can also change the Rotation/Scale
settings in Indigo's texture window for a similar result (when dealing with blend textures that is). For instance instead of :
1 | 0 | 0 | 1
0.01 | 0 | 0 | 0.01
There is this Indigo material called "null" wich does just... nothing. Blended with a metal material it would figure the holes by transparency. It is the method this perforated material is using, only that a procedural shader stands for the blend texture.