Cast iron signs - what colour painted when new?

[Nimbus]

Can anybody please tell me what colour to paint my cast-iron sign to represent an 'as new' state? It is one of the common LNER . BEWARE OF THE TRAINS . LOOK BOTH UP AND DOWN THE LINE... variety. In late BR days these seem to have had either white lettering and border on red background, or, red lettering and border on a white background. In early BR days I've seen one painted with white lettering and border on a GER blue background. Several on preserved railways today have white lettering and border on a black background - not very exciting! I've had the sign grit-blasted and sealed, so I'd like to get the 'top coat' right. Many thanks.

[Bryan]

I am wondering the same about signs from that other company. The Midland.
I have a tunnel milepost head and a very large limit of lift plate.
Both in Yellow with Black edging Is this correct?

[65447]

Hi Nimbus, I regret to inform you that the boring black background with the white lettering is the correct combination.

Don't forget to apply both priming and undercoats...