[Foreword: I have searched the forums and found many threads about "black spots", I think this issue is somehow different... mine are "black stripes"]

Here is what I get rendering in P7 with the setting further below: all lights (2 infinite, 1 spot and 1 point) are set for raytrace shadows (default bias: blur =0 min shadow=0.8) :
as You can see there are black stripes, quite visible on the skin of the character...

any hint on how to remove these ugly black stripes?! (other than editing / retouch )

use displacement bounds, decrease bucket size, set min shading rate to 0.01, normals forward, cast shadows, et al.

Quote - use displacement bounds

sorry, does it mean setting "min displacement bounds" to higher than zero? Which value You'd suggest?

Quote - normals forward, cast shadows, et al.

whats is "normals forward"?

My mistake: "cast shadow" was indeed selected already...

Thanks for Your help!

Lowering the shading rate below 0.2 usually won't help anything as long as the shading rate of the actors aren't lowered, too.

ya sometimes will get those bucket edge artifacts if displacement bounds are 0. this is covered in the manual. try 'em at 0.1, e.g. as with shading rate, this may be over-ridden by the object properties. in the above image, "cast shadows" is unchecked, but I just said that because it's wrong to render without shadows IMVHO. I doubt it will affect the artifacts, unless ya switch to depth-mapped shadows.

Thanks!
it worked just fine with following settings:

I added credit for both of You in my gallery

excellent work on that render, by the way. good scene composition, good shadows, good drapery, et al.

I get those black lines sometimes when I turn on Depth of Field. Always at the edge of the "buckets". Not related to your specific case here, but it must be a similar issue.

Quote - excellent work on that render, by the way. good scene composition, good shadows, good drapery, et al.

Thanks!

Quote - I get those black lines sometimes when I turn on Depth of Field. Always at the edge of the "buckets". Not related to your specific case here, but it must be a similar issue.

I have no experience yet with Depth of Field, but we will take good note of Your warning