Farrow and Ball - do I need the undercoat?

[IsItMeOr]

I know F&B divides people .

I haven't used it before, but have fallen in love with oval room blue, so planning to give it a go.

My question is, do people really use the special undercoats? It seems a lot of extra expense, when I'm planning to do a basecoat anyway, to deal with some hairline cracks and colour change.

We wished we had - although it was dark red not blue. The recommended undercoat was dark grey, we used cheapy white emulsion and it took 4 coats of the red to properly cover! Although apparently red is one of the more difficult colours according to the decorator.