When to use different colour primer

[John]

Normally I just use grey primer, Halfords, Vallejo or what ever else I have at the time, but is there a "rule" when to use grey, black or white?

I've just started a Revell 1/48 Spitfire and it has a red nose cone so I'm guessing to get it bright red I would be better using a white primer?

[Guest]

No hard and fast rule but a yellow primer under red gives it a bit more oomph.

The only 'not essential' but necessary rule is if the top coat is anything other than black or metallic the primer should be light, Grey or white.

I only ever use Humbrols matte, White, Black, Grey, or yellow as a primer coat, (depending on the top coat naturally, in some cases of course recently I'll use Humbrol rust as a primer as on the Ducati exhausts)

[stona]

I generally use grey as a primer too. I've applied the "difficult" colours (red,yellow,white) over it with no real problem but if I'm not being lazy I'd prime for them with white. m1ks point about red under yellow certainly makes sense,I might just try it.

Cheers

Steve