I was chatting with Jamie, the store manager at my local Warhammer store, about painting and he pointed out that there were lots of different colours for undercoat spray painting available. Depending on what you're painting, it might just be more efficient to undercoat a miniature in black or blue or red, and then just paint layers on top of that. That made a lot of sense to me, and I can definitely imagine a scenario when I'd want to spray a bunch of space marines red and then layer other shades onto it, I have to admit that lately I've really been enjoying the look of a white undercoat no matter what I'm painting. This might sound counter-productive, but I do have my reasons.
Before I explain my habit of priming my miniatures white, I'll issue a disclaimer. I'm not an expert painter by any means, and in fact I'm a lazy painter with the primary goal of playing games with miniatures that aren't boring. Also, what I think is an attractive paint job is just my opinion, and might not be what you find attractive. This blog post is meant to explain why I often use white primer, not to persuade you to switch to it yourself. Then again, it might inspire you to try something new.
I love Citadel Contrast and Vallejo Xpress Color paint. I love the look of high contrast paints so much that it almost pains me to paint with anything else. The more I can use either Citadel Contrast or Vallejo Xpress Color, the happier I am.
One thing about these paints, though, is that they don't really work against, say, a black primer, because they're usually not opaque. Some colours show up against dark primers, but generally they work best on a white, bone, or light grey undercoat.
I imagine that this renders a relatively vibrant result compared to something starting with a dark undercoat. Personally, I like my miniatures to be vibrant. The "comic book" look perfectly suits most of the board games and wargames I play. And vibrant doesn't always mean bright, either. I paint the black armour of chaos space marines starting with a white undercoat and Black Templar or Black Lotus, and it's both grim and dark.
One of the many good reasons you might use a dark undercoats is to conceal your lack of coverage. When you miss a spot on a miniature with a white undercoat, you see a spot of white. When you miss a spot on a miniature with a black undercoat, you see what's probably just a shadow. It's a very effective trick, and it works for spots you just can't reach as well as on tiny spots you sometimes get from the randomness of how a brush stroke falls.
Then again, one of the techniques professional painters use is edge highlighting. This is the process of going back over a painted model and painting impossibly-thin lines of light paint over just the hard edges of a miniature, to make the edges of armour and material stand apart from the rest of the model. It's sort of a fake lighting effect, but also a little like the inking process in comic art. It accentuates detail in an obviously illustrative way, while also hinting at photo-realism.
I love the effect. My problem is that I can't seem to achieve it. I rarely spend enough time on one miniature to make it happen, and my painting technique isn't yet what it needs to be for it to happen well.
I've found that a white undercoat, along with high contrast paints, can often suggest edge highlighting even when I've not actually done any highlighting. It's not uncommon for high contrast paints to fall away from outside edges, giving them a tint of colour without hiding the brightness of the undercoat.
With extra effort, you can encourage this by painting right up to an edge, but not on the edge. Then you have a noticeable white edge, which you can either leave white or use as a guide for some basic highlighting with your favourite lightly-coloured high contrast paint.
I don't literally only use white undercoating. I've used black on a chaos space marine, I've used gray, and bone, and others. Using a white undercoat isn't a philosophy or even a rule, it's just my current preference. But it's not as impractical as it may seem, and I've been really happy with the results.
Header photo by Seth Kenlon. Creative Commons cc0.