Tuesday, 30 October 2012

Gesso – the other primer

The discovery of gesso is only a recent one for me, but I wish I'd known of it sooner! After just one use I was sold and it has become one of my go-to hobby materials.

So, what is gesso?

Gesso is mainly used by artists to prepare canvases for painting. It is painted and stippled onto the canvas and when dry creates a nice, sealed, surface to paint on. It has a very slightly rough texture and creates what artists call a nice 'bite', which helps paint flow off the brush smoothly and easily.

However, and this is where our interests lie, it can also be used to prepare myriad other surfaces for painting. Essentially, this is an alternative to spray primers. So far I've used it on cork (a porous material), card and foam core board (sort-of porous materials) and plastic (a non-porous material) all with great effect.

Gesso is ... weird ...

Yes: gesso is weird stuff. Forget everything you know about priming and painting miniatures. Fine and delicate goes out the window in favour heavy and slap-dash.

Gesso has the most bizarre property of shrinking as it dries. Or more accurately, shrinking onto the surface its put on. When you apply it, you do so liberally. You totally obscure any details. But, as it dries, it shrinks and shrinks and by the time its ready all the details are visible again.

I'll show some photos by way of demonstration. I'm using cork to base my Space Wolves and I really wanted to seal the surface before spray priming as I'm not certain how the primer would look on the bare cork.
Before ...
This was taken just after I'd applied the gesso to a cork base. As you can see, it's been applied very generously. There's even bubbles in the paint!

This was taken the next day. You need to give gesso about a day to properly dry. Here you'll notice how it has shrunk onto the surface and all the details of the cork are still present. This should prepare the surface nicely.

What to use gesso for?

I know that many have had good results priming miniatures with gesso, but to be perfectly honest, I think it obscures too much detail. That's the thing with gesso, it's just not as fine as an aerosol primer. Because gesso is essentially a very fine material suspended in a medium, it does end up filling in some details. Not a lot, but it is enough to put me off using it for 'proper' miniatures.

However, what it is great for is things that don't require that level of detail: things like bases and terrain. I've used it to prime some scratch-built terrain recently, and it worked a treat. On the cork bases the minor 'filling in' of details actually serves to make the cork look more rocky and natural.

Beyond that, there aren't really any tips or tricks I can offer in using gesso as it is basically idiot-proof. You apply it like an exuberant child in an art class and leave it alone to dry. The only thing to watch out for is that a film of gesso can end up stretching across narrow gaps. If left unchecked, it can end up drying like that and forming a solid and brittle 'blade' of paint. Simply blowing the offending film 'pops' it, so it's nothing to worry about – just have a check over of the piece a few minutes after applying the paint and you should catch any problem areas.

As for brands, there are plenty out there. Gesso is readily available online and you'll find it in art stores. Most gessos come in black or white, but there are some grey ones available. I've even seen clear gesso which can be used as-is or have any acrylic paint mixed into it to create a custom coloured gesso. I've been using Bob Ross Grey Gesso because grey was good for the terrain project I bought it for, it came in a decent-sized bottle, and I like Bob Ross and his happy little trees.

Bob wishes you happy painting.
Have you used gesso? What applications have you found it works (or doesn't work!) for? Let me know in the comments.


  1. I use Gesso for everything! Priming, Terrain & Basing.

    I've found that if you thin it with a bit of water before priming it will pull into the detail better, thus avoiding loss of details. I love the stuff and wholeheartedly recommend it to everybody who's sick of bad spray primer ;)

    Razblood from the B & C

    1. Hi Razblood. That's a great idea about thinning the gesso, I may have to try that!