Black is 0, so 0 * -1 = 0, and your black doesn't invert. White is 1, so 1 * -1 = -1, and UE4 assumes 0. You can try adding -1 and converting the output to absolute value. 0 + -1 = -1 (abs = 1) 1 + -1 = 0 (abs = 0) I was looking for an alternative to OneMinus that I could parameterize. Make -1 a parameter value, and if you…
I'm usually too simple minded to think of using absolute value, I would just do X * -1 + 1 or if it's greyscale plug it into the alpha of a lerp with the default 1 and 0 values flipped, that's a real easy inversion that doesn't involve minus one.