Mix

The V-Ray Mix utility texture mixes two colors or textures using a texture map or a solid color value. 

UI Path: ||V-Ray Node Editor|| > Shader > Add > Texture Utilities > V-Ray Mix

Color 1 – Specifies the first color.

Color 2 – Specifies the second color.

Mix Amount – Controls the strength of the mix.

Mix Map – Input socket for the node that controls how Color 1 and Color 2 are mixed together.

Transition Upper – Used when a texture is applied to the Mix Map. Controls how gradual or how sharp the transition between the two colors is for the bright areas of the Mix Map. Any brightness value above this on the Mix Map will display Color 1.

Transition Lower – Used when a texture is applied to the Mix Map. Controls how gradual or how sharp the transition between the two colors is for the dark areas of the Mix Map.

Use Curve – 

Invert – When enabled, inverts the colors in the final result.

Invert Alpha – Inverts the alpha channel if Invert is also enabled.