Creating mask texture for very small parameter

[banana28]

Hi, the photo is the character I'm working on. I use VraySkin mtl.
I like over all skin tone, however, some place like eyelid is too blurry. I want [Medium Radius] become smaller around eyelid.
Currently, it is 0.05, so when I draw a black and white mask, radius for white turns out 1.0, and skin becomes too blurry.
Since the parameter is so small, I have a hard time figuring out how much value of black and white should I use.
Is there are any way to limit white to 0.05?
Or is it possible to know the black and white value for 0.05?

[piotrus3333]

output curves in 3dsmax bitmap or VRayHDRI? or mix map from two VRayColor maps?

[banana28]

output curves in 3dsmax bitmap or VRayHDRI? or mix map from two VRayColor maps?

Hi! Thanks, I've never used VrayColor, and it seems I can input specified value there, so yes, it is good idea I'll give a try!