Colour of original primer (undercoat?)

[MGFmad]

I have a 1968 smoke grey Traveller that I am currently preparing for repainting. On stripping back the old paint, the build up of paint is as follows. Steel, black (primer?), red (primer?) green then the smoke grey top coat.

On first discovering the green colour my first thought was that it must have been painted green (a slightly darker shade than almond green) before the smoke grey, yet when you look uder the dash and all the areas that never get painted in a re-sparay, its all the smoke grey shade, the interior is all blue and now that I have got the cars detailed history, its original service history even states smoke grey.

It cannot just be replacement panels as the windscreen surround also has this green shade. Is this some form of undercoat?

[tortron]

on my 51 four door (may or may not be a ckd) in grey
it goes steel, black, red and in places a further layer of black

[bmcecosse]

Very probably a PO sprayed the car green externally - without worrying about the hidden parts!

[jaekl]

There may have been some variation in the primers used. The red and green is very common. The only black or dark brown primer I've seen was on a friends car and it was very difficult to get off. I believe either of these priming steps were only done on the main body. Wheels grilles and bumper valances didn't get the red/green process. As I recall they only had a dark prime.
The dark prime must have been part of the dip or roto process. The red and green when used was applied only in areas that would get color. So up under the dash is usually dark.