When you start painting a model, one question comes up early: where in the sequence do the shadows and highlights actually go? Short answer: pre-shading builds your shadows before the base colour; you spray dark into the recesses, then lay a semi-transparent colour over it so the dark lines read as shadow from within. Post-shading does the opposite, adding shadow and light after the base colour. And rather than picking one, you get the richest result by combining the two.
In truth these aren't separate techniques but a timing decision: they define where in the painting sequence you put your light-and-shadow information. Both crossed over from vehicle modelling into miniatures, and today they sit at the heart of most airbrush workflows. If you're starting out, post-shading is the more forgiving of the two; as you gain experience, you start blending them together.
What is it and what's it for?
The names sound technical, but both describe a simple idea. Pre-shading and post-shading are two approaches that decide when you apply shadow and light relative to the base colour. So the real question isn't "which colour goes dark" but "where in the sequence do I place the dark and the light".
With pre-shading you build the shadow (and sometimes the light) before the base colour. The classic example goes like this: after priming, you spray dark into the recesses and panel lines, then lay a semi-transparent base colour over the top. Because the top colour doesn't fully cover, the dark lines underneath read as shadow through it. That's why zenithal priming is itself a form of pre-shading.
Post-shading, by contrast, comes in at the end. You lay the flat base first, then afterwards add dark into the recesses (shade) and light onto the raised areas (highlight). Colour modulation, which means keeping panel centres light and edges dark, is a textbook post-shading application.
Pre-shading or post-shading?
You don't have to pick just one; they're not rivals but tools for different jobs. Pre-shading delivers shadow from "inside": the dark value underneath modulates the brightness of the semi-transparent colour on top, so transitions come out natural and smooth. The cost is subtlety, because if the top colour goes on too opaque it smothers the pre-shade and your work disappears.
Post-shading, on the other hand, is far more controllable and correctable. Shadow and light go on "from above", so if you don't like a transition you simply go over it again. Its cost is skill, since keeping those transitions soft and free of blotches is entirely on you.
If you want a rule of thumb, think of it this way: pre-shade for large single-colour surfaces and speed, and post-shade when you want control and the option to fix. Most experienced painters, though, use both.
There's one more difference worth knowing. Pre-shading takes planning, because you decide where the shadow goes at the start and going back later gets tricky. Post-shading lets you decide at the end; you look at the model and add to wherever you think "that area should be darker". In short, pre-shading is a technique of foresight, post-shading one of reaction.
How does it work?
To grasp the logic, it helps to look at each one on its own. Pre-shading relies on an optical trick, so think of it a bit like glazing. A semi-transparent layer doesn't fully cover the value beneath it; the dark line underneath darkens the top colour right at that spot. The result is a map of light and shadow built without drawing each shadow by brush.
The logic of post-shading, meanwhile, rests on layering. In the spirit of layering and washing and shading, you add controlled darks and lights on top of a finished flat base.
A principle Vince Venturella returns to often: rather than collapsing shadow and light into a single step, think in terms of value, that is, lightness and darkness. The pre-shade sets the foundation and the post-shade reinforces the accents; both are two ends of the same value logic.
This is exactly why combining them gives the richest result: a zenithal or pre-shade establishes the underlying light and shadow, and then the post-shade sharpens depth and accent on top.
How do you do it step by step?
Now that the theory is clear, we can move to practice. The method below merges pre-shade and post-shade into a single workflow. The airbrush is the most common tool, but you can do every step with a brush too.
- Pre-shade: After priming, spray dark into the recesses and panel lines, or build a zenithal directly (dark from below, light from above).
- Semi-transparent colour: Lay the base thin and semi-transparent. The goal is for the dark lines underneath to keep reading as shadow, so don't smother them in one pass.
- Post-shade (shadow): Once the colour has settled, deepen the shadow by adding a transparent dark tone into the remaining deep recesses.
- Post-light (light): Spray a lighter tone onto the upper surfaces and panel centres, keeping the light as if it comes from a single direction.
- Detail: Finally, finish with edge highlighting, a pin wash, and brush touch-ups.
Which paints and brushes?
Because this is really a decision about technique, you don't need special materials; for the most part you work with what you have. That said, a few things make the workflow noticeably easier:
- Airbrush: The most common tool; ideal for smooth shadow-to-light transitions across large surfaces.
- Semi-transparent paint or glazing medium: Pre-shading only shows through transparency, so thin your paint or use a glazing medium.
- Dark and light tone pairs: A dark for the pre-shade and a light for the post-light, both picked from the same family as your base.
- A good detail brush: A size 0 or 1 does the job for the edge highlight and pin wash steps.
Before investing in an airbrush, reading airbrush zenithal preshading and airbrush highlight and shadow will help clarify the whole workflow.
The most common mistakes
Almost every error here comes from a lack of subtlety and softness. The usual suspects are these:
- Smothering the pre-shade: Lay the top colour opaque and the dark lines underneath vanish completely. That's why a semi-transparent coat is non-negotiable.
- Hard, blotchy post-shade: Leaving shadow and light with sharp edges stands out badly. Transitions must be soft, so build them up in thin coats.
- Overdoing it: Pushing both pre and post too far produces an over-contrasted, "dirty" model.
- Inconsistent light direction: If the pre-shade comes from one direction and the post-light from another, the eye gets confused. Pick a single source from the start.
Pro tips
A handful of small habits can take the result from amateur to master:
- Combine the two: A pre-shade plus post-shade gives the richest result; one sets the foundation, the other delivers the accent.
- Keep the top colour thin: Whether the pre-shade shows at all depends entirely on transparency.
- Dose by scale: Dramatic contrast looks great on vehicles and tanks; keep it more measured on infantry.
- Finish with edge highlight and pin wash: These two sharpen and complete the airbrush shadow-and-light.
- Stay in the colour family: For colour modulation, keep panel centres light and edges dark, which is itself a post-shading application.
Frequently Asked Questions
Are pre-shading and post-shading the same thing?
No. Both deal with shadow and light, but the difference between them is timing. Pre-shading builds shadow before the base colour, post-shading after it. The pre-shade comes from within and looks natural; the post-shade is added on top and is more controllable. At an advanced level, the two are merged into a single workflow.
Do I need an airbrush for pre-shading?
No, you don't. The airbrush is the most common and smoothest tool, but you can build a pre-shade with zenithal priming or slapchop too. You can even apply the same logic by brush, painting dark lines and glazing semi-transparent colour over them; the only difference is that it takes a bit more patience.
Does zenithal count as pre-shading?
Yes, it does. Zenithal priming builds light from a single direction and places shadow before the base colour, which makes it a textbook form of pre-shading. Prime dark from below and light from above, then paint with a semi-transparent colour, and the value map you built reads through the base.
Why doesn't post-shading get smothered when pre-shading does?
Because post-shading is added over a finished base, so there's no information underneath to lose. Pre-shading, on the other hand, depends on the dark lines beneath showing through the top colour. Apply that colour opaque and you cover those lines, so the pre-shade disappears. That's why semi-transparency is vital in pre-shading.
Which is easier for beginners?
Usually post-shading, because it's controllable and correctable; you can go over a transition you don't like. Pre-shading leaves less margin for error, since the wrong top-colour transparency smothers the whole foundation. If you're starting out, we'd suggest getting the post-shading logic down first.
Is using both on the same model overkill?
On the contrary, the richest result comes precisely from combining them. The pre-shade sets the base balance of light and shadow, and the post-shade reinforces accent and depth. The only danger is overdoing it; pushing both too hard creates an over-contrasted, dirty look. So dose it with restraint.
What colour should a pre-shade be?
Usually a dark grey, black, or a darker tone of the base colour. But pure black is often too harsh, so most painters get a more natural shadow with dark grey or brown. What matters is staying in the same value family as the top colour and keeping a consistent light direction.
Key takeaway: Pre-shading builds shadow first, post-shading second, but one rule governs everything: keep the top colour thin so the information underneath keeps showing through. Combine the two with restraint, then finish with an edge highlight and a pin wash.
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