Mk 1 mx5 - what primer was used on classic red?

What colour of primer did Mazda use at the factory when spraying the classic red when the cars were new?  Know its a bit of an odd ball question but know from past experience that primer does affect final colour.

A Google image search on accident damaged MX-5s shows cracked and bent body panels which appear to show white primer. Halfords quote red primer for Mazda Classic Red.

Confused of Lincoln.

Mhy red roadster was owned by a tuning shop owner, who machine polished it every month. All the edges showed white primer.

As I recall, body shops worked with 3 different shades of SU red.

Mine appears to have white primer

 thanks guys. White makes sense I guess as I t makes the red brighter. I  did notice that on the Halfords can about it needing red primer, thought that a bit strange! 

Going to be tidying up the sills as previous owner had them painted black but it’s a really poor job. Going to buff them down and do them red, then will decide if I want to do the black part again or leave red.

The Halfords Red won’t match, unless you are getting the custom mix.

Warning on sills; if you see bubbles in the paint, which when rubbed back reveal unusually bright metal, look very carefully foe a tiny pin hole in the metal. Sills rust from inside; I have seen on cars the pin hole forming, and the weeping water will lift the paint like a small bleb. It doesn’t mean the sill is going to instantly disintegrate, but perhaps a hint not to spend too much time on a paint finish.

Pretty sure I’ve read that all NAs were primed white. My very dark green VR-Ltd was.