Unity 2017.4 For the UnityEngine.UI.ColorBlock : The inspector is incorrectly clamping the color multiplier to be between 1 and 5. However, you should be able to use a color multiplier of 0. If you create a ColorBlock via code, the default color multiplier is 0. This can be assigned to the button via code. Furthermore, I can go into Debug Inspector Window view and manually assign a value of 0. SO it's a bug with the inspector GUI?