Need help with screen colour filtering

I am making a time stop script for fun and I want to know how I can get that grey effect where everything on the players screen is grey including the parts in the workspace. Can someone tell me how to do this?

You can insert a color correction effect into lighting. From there just set its Saturation to -1. If you want inverted colors set it to -2.

I can’t find it. Do you think you could write a a few lines of code to show me what you mean?

well ColorCorrectionEffect existed, so hope that it will explain