Having an issue with eyelash shaders, So if I use diffuse or PBSDF with color set to black both sides of the roughness scale cause issues. Low roughness and the lashes look nice and black like they should  but now they are glossy and reflect light back. High roughness and the lashes no longer reflect but now they turn dull grey and don't "pop" like lashes would with mascara.

My solution is to use the same trick I use on eye pupils: Use no shader at all, total blackness in any light condition. Have a look.

So I guess if you wanted dark brown eyelashes, you would run the transparency map through an HSV2 or Simple_Color node, color the chip, and connect it to Closure2 on the MixClosure node.  Neat Trick for black lashes.  Thanks.

I don't know how you come up with these goodies, but thank you from me as well. 

@hborre The transparency map is not providing any color. one side of the mix closure is transparent the other side goes into the void providing a solid black color because it is rendering nothing. It's like when you have two facing mirrors and not enough glossy bounces. Eventually the renderer runs out of stuff to render and renders pure black. this will not work if you want brown lashes or any other color. I never use anything other than black for my lashes anyway unless I'm rendering a male figure.

@Miss B thanks!

It makes sense.  The more you simplify your shaders, the less you need to put thought into how you approach a Material Room problem.  I'll definitely use this approach, it reduces a character's overhead in the Material Room department.  Definitely keep these tips coming.