Paint in oil - or come to that, acrylic - that is? These days, since the example set by the Impressionists, I would guess that the majority of us paint 'alla prima', or in a variation thereof. In other words, we do a minimum of underpainting, we don't bother with the red bole ground (for example), and the 'dead layer' or 'grisaille' stage practised by the old masters. Indeed, there is some confusion about what constitutes an old master - some thinking the term could be applied to Cézanne or Monet, as well as to Vermeer or Rembrandt. In fact of course those painters used very different techniques. I thought of this while watching a demonstration on YouTube by the late Tom Keating - he made the point that Constable used the old master technique, employing the dead layer on a red bole, ('dead layer' meaning just absence of colour) before glazing and scumbling over the top. I don't know if Constable invariably used this method, and I suspect that Turner didn't - but there's a clear divide between pre- and post-Impressionist artists, the latter informing the techniques of most painters today. The advantage of alla prima - which doesn't really mean that you start and finish a painting in one sitting, although of course it can - is that the result is likely to be fresh and immediate, not laboured, academic, and over-cooked. On the other hand, there's no reason why an underpainting on traditional lines has to be dull and static - you can go as mad with it as you like; the subsequent glazing and colouring should still reveal the vigour of brushstrokes and vibrancy of composition. Because I have to work fairly slowly - or more accurately, I can't work for very long on a picture before stopping for a rest - the traditional approach rather appeals to me: I've used it twice - once in an oil painting which on reflection just didn't work at all (because the underpainting wasn't good enough; I hadn't brought it to a sufficient level of completion to glaze over the top with any success) and once with an acrylic. If I can find the latter, I'll post a photograph - and if I can't, it's Cliff and Critters, in my gallery somewhere. The latter showed the disadvantage of the method - unless you remember to create areas of white, the overall effect can be a bit dark; this, in oil, is what Underpainting White is made for; in acrylic of course you can use whatever white you like. You could also use Alkyd White in oil - be careful of Titanium, though; and certainly don't use Zinc. I don't know that it's a method I'd use just for the sake of it,or for nostalgia's sake - that savours of confusing the medium with the message. But now and then, it's worth a play; and I wonder if anyone these days uses it as a method of making pictures?