Ok I have a couple of sci-fi/wargame ‘mecha’ style figures on the bench and in the stash, now I wasn’t sure what colour I was going to paint them then I was gifted with a bottle of Orange-Yellow gloss paint to try, so that decided the colour. Now I use Mr Hobby Mr Surfacer spray primer and have the following colours; Black, grey, white and red oxide, the question is which would you choose as the primer base for a orange-yellow top coat?
Probably not the black.
I haven’t tried it myself yet but my understanding is that Tamiya pink primer is optimal for colors like that.
The red-oxide could drag the orange over to reddish.
Grey should make the orange slightly darker than the white.
Test orange with grey and white on some other surface first.
I always understood that white was the Go-To advice - although that may have been for a Day-Glo effect as seen on my Blu Water (air-launched version):
Still a work in progress I hasten to add.
I would use silver. Tamiya LP-11 if you have easy access to it. Reds and yellows show up well and true over silver….
It all depends on what the desired final effect is.
What I’ve learned from others: Use white as the base primer before applying reds, orange or yellow. This makes them really stand out. HTH.
—mike …
White
Thanks all for your feed back, I’ve had a look for the Tamiya pink but the only places that seem to have it are not in the UK and postage is more than the primer costs. I did however find someone that does yellow primer, I’ll order a can then try it against white and grey primers and see which one gives the most pleasing result.
If you wan to test it, try a gloss black base coat before the yellow orange. Spray the yellow-orange on thin layers until you achive the result you like. 
I’ve used pink quite successfully under a yellow top coat, and MRP do an excellent pink micro filler primer as do Mr Surfacer.
That said, some time ago, this one had good old Mr Surfacer grey as a primer. Judge for yourself!
Pink! Yellow and orange go down best over pink. Mix your red and white primers and hey presto. The more red you use to make the pink, the deeper your orange overcoat will be.
Cheers
Matthew
so he would be in the pink if he mixes red and white?
It’s not pink, it’s… pale red.
So I put the red down first then the white or the white then the red?
I did say in the first post I’m using spray primers from a can.
Absolutely no chance of an airbrush?
Yes I have a brand new compressor and a new airbrush but ALL my priming has always been done with rattle cans, be it aircraft, ships, tanks or wargaming figures.
I use Tamiya, Mr Surfacer and Army Painter spray primers, never had a problem so never needed to shoot primer through an airbrush, and most likely never will.
Spray cans can be be “decanted” into can, mixed and sprayed using an airbrush.
Wild idea: One spray can in each hand then “mix on the go” while spraying both at the same time.
I’d give a brass or bronze undercoat a try, with, maybe(?), a final thin coat of clear orange just because.
