"Not to much of a deviation"?
On this Forum? 

It is a vaild point, it is about undercoating. 

Can't help you though, I don't use black, as it stops me seeing the details. Also painting Prussians, I can't tell what I've already done.

Quote from: FierceKitty on 12 January 2019, 11:55:48 PM
I hope this isn't too much of a deviation, but why does black undercoat sometimes bloom through and wreck a paint job? It seems a hazard with certain colours in particular; scarlet and orange seem vulnerable.

It has something to do with the pigments.  I recently learned the way to fix this is to paint the area grey or tan first.  I've picked up a number of great painting techniques on the Tabletop Minions YouTube site. It tends to favor 40k which I don't play but I do find the content interesting and useful.

https://youtu.be/gLbd4_RSwU8

I've found a white undercoat on the bright areas works. But it's obviously extra labour, and so a horror to my soul.

Quote from: FierceKitty on 12 January 2019, 11:55:48 PM
I hope this isn't too much of a deviation, but why does black undercoat sometimes bloom through and wreck a paint job? It seems a hazard with certain colours in particular; scarlet and orange seem vulnerable.

From my understanding lighter colours are transparent, when darker ones are opaque. For that reason I use a white/gray undercoat. But that also means you'll have to put more time to painting to get everything covered.

Quote from: FierceKitty on 12 January 2019, 11:55:48 PM
I hope this isn't too much of a deviation, but why does black undercoat sometimes bloom through and wreck a paint job? It seems a hazard with certain colours in particular; scarlet and orange seem vulnerable.

Use brown, keeps figures bright in 10mm.

I usually use grey.
Black eats light so can't see detail, and hard to cover.
White reflects too much mm light, so hides detail.