rules for non yellow number plates please

[chrisdadd]

I have a midnight blue chim and I would like to change the N plate colours to be silver letters on black but someone said they thought that was illegal on cars less than 20 years old...

What are the rules please?

[Bodo]

I guess the deadline for black plates is 1973?
You may use self reflecting plates olden than that, but not vice versa:
no black plates on cars first registered past deadline.

[Bodo]

see the rules here:

www.dvla.gov.uk/vehicles/regmarks/reg_marks_current_requirements.htm#traditionalplates