Getting a uniform finish with emulsion paint?

[AMc]

I've had this problem in the past with F&B dark reds. Always a b*$£er to get uniform - something to do with pigment density.

I've used a few red and pink paints from various manufacturers and always struggled to get an even finish. A pal of mine who is a trained artist said that it is a feature of the pigment and while you can minimise it, red will always be the hardest colour to get properly flat