Contrast Enhance not valid?

trying to create a slider to control the image effect contrast enhance, but it gives me compiler error “The name ‘ContrastEnhance’ does not denote a valid type” even though i have
import UnityStandardAssets.ImageEffects; added which allows me to access the other effects. what is not working with this one?

It’s a missing “public” keyword for the class definition in the script. I have reported the bug to Unity. You can fix it by adding “public” in front of “class” in ContrastEnhance.cs.