Diffuse Lighting in Rhino 6

Dear all,
I’m trying to get a display mode that shows surfaces as flat colours (Mac) – for the purpose of a material ID export. In Rhino 5 I know that could be achieved by assigning materials and unchecking enable diffuse lighting. That tick box isn’t present in Rhino 6. What’s the equivalent setting?
Thanks in advance,

You can do this in Preferences > Display Modes by switching the Lighting Scheme in the General section of a Shaded mode copy to “No Lighting”