They look a lot alike. They smell a lot alike. If you’re using a brush-on primer and lick your brushes back to a point after rinsing (and you should lick your brushes back to a point), they even taste a lot alike.
But paint and primers aren’t the same.
And you shouldn’t use paint as a “primer”.
And you should always prime your miniatures before painting.
Primers adhere to a new surface and prepare it to receive paint. Without it, many paints just won’t stick, and if they do, they certainly won’t stay long. Using them increases the durability of your project, and gives you an even and uniform space to begin the fun part of miniature painting.
To really understand why priming your miniatures is necessary, you should learn what the materials actually are.
What’s the Difference Between Primers and Paint?
They’re two separate things! And they each do something the other doesn’t.
The Main and Most Important Difference, or The Pro-Primers Elevator Pitch
Acrylic paint isn’t designed to bond tightly or adhere with surfaces like plastic, resin, or metal.
Applied directly to a miniature, acrylic paint may go on more or less as expected, but can be uneven, dry to a brittle or shiny finish, and is much, much more prone to chip and scratch easily (not so great for game miniatures). Even simply turning a miniature in your hand is enough to rub unprimed paint off bit by bit.
And have you ever tried applying thinned paint to an unprimed resin miniature? The paint will immediately bead up and roll into recesses.
Simply put, if you want your paint job to have consistent color that will stay where you put it, primers are your solution.
Acrylic Paints Explained
Water-based acrylic paints – like all the pots of Citadel paints on your bench, Vallejo Colours, Army Painter, and even those less-expensive craft store paints we’ve all gambled on to mixed results – are designed for a specific purpose: to provide uniform color and coverage.
Water-based acrylic paints are pigments suspended in a water/polymer emulsion. (Brands have their own proprietary formulae, but all acrylic miniatures paints follow this basic formulation). Depending on the ratios of this mix, acrylics can be extremely thick, or airbrush-thin.
Typically, high-quality acrylic miniature paints contain a much higher density of pigment, which allows thin coats to cover better (which, in turn, helps to preserve very small details on your minis). That’s the primary reason they’re pricier than their craft store counterparts, and why priming a surface before applying them always yields better results.
Primers are paint-like substances chemically formulated to do their own specific task: bond with a surface to prepare it for paint.
Primers not only ensure a strong foundation and consistent texture for your paint coats; they protect your work from the foundation up because they’re engineered to prepare a surface properly, and hold on to your paint.
Brand by brand, primers can contain any number of ingredients that help them do their job.
In the case of spray primers (in rattle cans): pigments, acrylic polymers, resins, and other substances are dissolved in a solvent. These are atomized using a propellant, creating a superfine mist of small droplets.
Those droplets cure when the solvent evaporates, and form a tight bond with your miniature’s surface to create a durable and even space for your paints.
Brush-on primers work in a similar way, and contain similar compounds.
The Dos And Don’ts of Priming Miniatures
Priming gets easier the more you practice, and along the way you’ll find what techniques, products, and colors work best for you. Here are some best practices and tips to help you get the best results in your own paint jobs.
DO: Prime Your Miniatures Before Painting
Yep, every time.
DON’T: Forget to Wear Safety Equipment
If you’re spraying, you should wear a mask. Gloves help protect your digits from both chemicals and overspray, which is tough to wash off.
DO: Understand The Materials For Which Your Primer Is Intended
Not all primers are the same! Not all miniatures are made of the same material, either.
The propellants and solvents in spray primers behave badly when applied to certain materials. This can be as simple-but-frustrating as a sticky texture, or as catastrophic as melting your miniature. Resin miniatures are particularly finicky.
Read the labels of both your primers and your miniatures to be sure you know they’re compatible before you start.
DONT: Forget to Wash and Prep Your Miniatures Before Priming
Most miniatures are made using moulds. To help the models or sprues detach after casting, manufacturers apply a lubricant to the moulds before pouring or injecting the casting material (plastic, metal, or resin).
Think Pam Cooking Spray, but instead of crispy, delicious waffles, they’re tiny toy soldiers.
That lubricant, which is called mould release, is likely still on your miniatures when you pry them from their boxes, and it will stay until you wash it off. If you don’t, your primer (and sometimes your paint coats) will be affected, and…just won’t stick.
There’s no secret trick to getting rid of mould release: just use warm water, dish soap, and an old toothbrush.
Any other prep work your miniature needs, like filling gaps, scraping away flash, or adding kitbashed bits, should be completed after you wash, and before you prime, as well.
DONT: Use Spray Primers When It’s Too Cold
You should prime outdoors whenever possible, because primers are chemicals, and huffing chemicals isn’t where it’s at. That means temperature plays a big role in how well your primer is going to perform.
Rattle cans use pressure to atomize their contents. Pressure responds to temperature (raising temperature increases pressure; lowering it decreases pressure). The depressurization that happens when you hold down a rattle can’s nozzle also lowers the temperature of the primer inside the can. All the chemicals in the primer itself are also temp-sensitive, and much like many humans I know, just won’t do the thing when they’re too cold.
Atomized droplets sometimes freeze between the nozzle and your miniatures, too, if it’s too cold.
So, low ambient temperatures, 50° and below, will negatively affect your primer’s application, fom sticky coats, to pebbly, uneven texture, to making a gloppy mess. There are lots of hacks and tricks from painters on the web for spray priming in cold weather, but in my opinion: opt for brush-on primers in colder months.
DO: Apply Primers Correctly
Instructions for these processes will vary. Always read labels, and remember to test before you apply.
How to Apply Spray Primer to Miniatures
When your minis are washed, prepared, and fully dry, attach them to a surface you can easily pick up and rotate. A board or a flattened Amazon box are my standards.
Sticky Tack is a tool every miniature painter needs in their kit, and works a treat for securing models down to be primed.
Shake your can of primer well, and perform a test spray on the cardboard. This will clear dried gunk and excess fluid from the nozzle; it also allows you to see if your primer is sufficiently mixed.
Hold the can upright, never at a sharp angle, not sideways, and certainly not upside-down. This causes excess propellant, not primer, to shoot out of the nozzle.
Gently spray your miniatures in short, quick pulses from a distance (6-12 inches usually does the trick, but you may have to adjust according to wind or to avoid spraying your barbecue grill – trust your gut and go slowly).
Move the rattle can while spraying to avoid overapplication.
How to Apply Brush-On Primer to Miniatures
Typically, a brush-on miniature primer’s label will read something like “acrylic-polyurethane surface primer”, and also provide directions for use.
Remember that not all primers behave the same way, so default to those instructions when necessary (and save yourself a headache by testing new primers on old miniatures or plastic sprues before you apply them to a model).
In the case of most brush-on options, don’t thin the primer. Instead, use an ever-so-slightly damp brush – rinsed and squeezed of its excess water – to apply thin (THIN) coats. I like to use a fluffy brush that’s actually designed for applying eyeshadow. It allows me to carry a fair amount of primer in my bristles, alternate easily between strokes and stippling (to get primer into those details), and helps the process go a bit faster than if I use a smaller brush.
It’s unlikely you’ll achieve full coverage in one coat of brush-on primer, so don’t sweat the streaks or unevenness. Be patient, work in sections, and let the whole thing dry before you decide a second coat is called for.
Oh, and one more thing: you’ll likely encounter tiny air bubbles when using brush-on primers. Do your best to brush them away while applying your product, and give your miniatures a good puff of air from a few different angles to pop them before you set the model to dry. Bubbles are annoying, but they’re unlikely to ruin your overall project, and easy to get rid of before the primer cures.
Have A Dedicated Primer Brush
Brushing on primer often involves a lot more than just brushing. To prime all of the small details, peaks and valleys, and indentations in a miniature, you’ll need to alternately brush and stipple.
Stippling is a painting technique: using a brush to press paint onto (and in the case of minis, into the recesses of) a surface. It’s the opposite of a composed, confident brush stroke, and feels like tap-tap-tapping when you’re doing it right.
Stippling can be tough on brushes (as can be the resins in primers), so choose a brush for your brush-on miniature primer that’s used only for priming. A tapered round, full brush works great, but so will old or worn-out brushes you can’t bear to part with. Don’t bother with anything smaller than a size 2 brush in most cases – much too small for the task.
And don’t forget to wash it.
DON’T: Attempt to Fully Cover A Model In One Coat
It’s a recipe for pooling, dripping primer. Rotate your miniatures between pulses and adjust the angle at which you’re holding them (this is why you’ve attached them to a mobile painting surface), with the goal of applying a thin “dusting” evenly on the entire miniature.
(above: coats of spray primer should be a light, directional dusting. The above photos show the first coat of white primer on a black miniature in order to illustrate a proper coat)
Let the coat dry completely, and, if necessary, a second thin coat of primer can be sprayed to complete the coverage. It doesn’t take much primer to get where you need to be. This goes for both spray and brush-on versions.
Thin layers allow the miniature’s details to remain. It’s as simple as that.
If your model looks wet or plastic after the primer has dried, you’ve overprimed. Prevent this by going slowly and thinking in multiple coats instead of one.
DO: Use Different Primer Colors For Different Projects
Black or grey primer will suit a majority of projects. But what about white? Or other colors?
The second thing primers do is provide a uniform base color, which gives the paint colors you apply over it undertones. You can use those undertones to your advantage when painting.
Undertones are part of color theory, an immense topic for another article. They’re important, but I think, in the end, the question of what primer you ultimately choose actually comes down to your own personal preference, and has a lot to do with your own style of painting. Lean into that.
Here are a few tips for the most common primer colors for miniature painting:
When to Use Black Primer
Using black primer allows you to more easily create contrast with paint. Since miniatures are so miniature, contrast is really important. A nice black primer lets you paint “up” from your shadows using lighter colors, instead of applying shadows atop your light colors (as is the case when applying washes or inks). The shadows are more or less taken care of already; your job is to use color and highlights to bring depth to your model.
Black primer is perfect for miniatures that will be painted mostly with metallic paints. Models like mechs, heavily armored figures, and droids are much easier and faster to paint when primed black.
Avoid using black primer on minis that will primarily be painted with very bright colors. If you’re hoping to achieve a glowing or bright look, as with fire or radiant magic, best to use white.
When To Use Grey Primer
Grey primer is a safe choice if you’re unsure what your finished project will look like just yet, or just as a general go-to color for priming anything.
It takes fewer coats to paint “up” from grey, but it’s also less dramatic. You’ll spend less time highlighting vibrant parts of your model, however, and laying down base coats of color. Worth mentioning, too, is that grey primer makes it easier to see all the fine details of a model than black primer.
When To Use White Primer
Any miniature that will primarily be painted with vibrant or light colors (like yellow or light pink) will be easier to paint if you begin with a white primer.
It also makes colors more vibrant. When light passes through your paint layers, some of it bounces off the white surface of the primer layer and back through. That helps make your colors more clear and bright than painting them atop a grey or black surface.
White primer also allows you to see the details of a model much more clearly than grey or black. Particularly difficult, small, or detailed models can benefit from it.
(above: the same miniature, Fire Brand Kobold on Ember Rage Fire Snake, Steamforged Games, primed in black, grey, and white; also pictured: my couch, where I do not paint)
DONT: Mistake Primer with Undercoat
While primers are applied before painting a new surface, undercoats are used before painting a surface that has already been painted. In other words, a primer is never an undercoat, because primers, in the sense we’re discussing them here, are always applied to a new surface.
The first base layers of paint you apply are technically an undercoat, because you’ve applied them to a primed surface and they will receive more color over the course of your project.
This concept is confusing because many people conflate undercoats with undertones.
DO: Allow Primers to Fully Dry Before Painting
Most primers sold for miniature painting need only a short time to dry enough to receive paint. Army Painter sprays – the primers I personally use – are usually ready in 20-30 minutes. Others will vary, so read your labels (and follow the instructions).
When it’s dry, you shouldn’t notice any stickiness, harsh chemical odor, or plastic-looking shine. If you’re not sure if it’s dry, set a timer and come back in ten minutes.
DON’T: Be Afraid To Experiment
Especially in the case of using brush-on primers, try using different colors on various parts of a model to achieve different effects, like a coat of white on a torch flame, or using spray primers in black and white to try zenithal highlights.
Primers come in more than black, grey, and white, too. Mixing it up once in a while can result in fantastic paint jobs and interesting effects, and can even save you a lot of time if you choose a primer color that matches your overall color scheme.
TL:DR: Prime Well and Prime Often
Priming is the first step in painting durable miniatures. To ensure that your paints work the way you expect them, and maintain a uniform bond to your model, it’s a step you just can’t skip. Any primer is an essential base from which to begin work.
If you skip priming, or attempt to cut corners by using paint as primer, it will cause problems. Preventable ones!
The do’s and dont’s outlined above, when practiced regularly, will help your miniatures look their best, and last through hundreds of sessions.