Make picture in camera black and white

Hello.
I need to make all items black and white except few others, for which now i’m setting custom depth to true.
But it’s useless until i can’t make all other things in black and white colors.
How can i change the materials and so on to be white and black for terrain and static meshes?

You could use a postprocess volume and a postprocess component on the player camera. There is an option for black and white if I remember correctly.

You could also try and follow this tutorial which will let you do what you want within a certain radius: