Two-Sided V-Ray Material

Is there in issue with two-sided V-Ray materials? I have some plants using them The first slot is the bitmap, the second slot has nothing, and the blend is 50%. The object is rendering either all black, or all white.

Scene/Screencap will be helpful. Otherwise, check the docs.

In a two sided material, the first slot should be a vraymaterial, not just a bitmap. Not sure how that’s even possible. The best way is to enable thin-walled (no refraction > black).
Set SSS illumination to Uniform, put the translucency map in the SSS color and the SSS amount around 0.3-0.5 depending on the look you’re trying to achieve. In the back material you can have a desaturated/brighter and less reflective material with the same settings as previous for SSS.