Lines come up in rendering after adding hair I made a few color changes to this model and added hair. Now, there are some strange lines showing up in my render.

The material of the head is a mix of translucent BSDF, glossy BSDF and two subsurface scattering nodes. The hair is using the same material as the head. It is set for 1500 samples and took around two hours to reach 60%. At that point, the lines became a major concern for me and I starting searching for possible reasons though I have not found any yet. So, what are these lines and how can I get rid of them?

I am using CPU rendering but i don't think that could be the cause of it as the problem is with the hair Also I am using blender 2.77 

.blend files:



node setup


before


Here is a picture after adding adding the hair
Try changing the dropdown menu in Hair BSDF from Reflection to Transmition. This helped when I downloaded the .blend file.

You could also try lowering the samples, as you said the problem only appeared when the count got up high. In the image rendering from the .blend file, noticable changes stop around 300-400 samples. More than 250, in general, just makes you feel better without actually changing anything.

Hope this helps and happy Blending!