LED Source Lighting: Real Light in a Mini

Short answer: LED source lighting hides a tiny LED inside a model or its base so a sword, lens or reactor physically glows. Where OSL fakes light with paint, this technique produces the light itself. That makes it a method for display pieces, dioramas and showcase models, and it asks for a little electronics know-how.

Let's be clear up front: you don't do this to every trooper in a gaming army. It really comes into its own when you want to crown a single cabinet piece, a centrepiece commander or a diorama with a detail that genuinely lights up. Here, if half the job is the brush, the other half is the drill and soldering iron.

What is LED source lighting and when do you use it?

At its simplest, LED source lighting places a real light source in the model, usually a tiny SMD LED, to actually illuminate its parts. As a result the sword really glows, the lenses really light up, and the reactor really shines.

It helps to pin down the distinction. OSL (Object Source Lighting) paints the illusion of light, while source lighting physically produces it. Even so, they aren't rivals; they're partners. The LED gives you the glowing core, and a painted OSL halo softens the transition around it.

This is exactly why source lighting sits firmly in the advanced bracket: it pulls in both modelling and small-scale electronics (LED, resistor, power) at once. In return you get an effect flat paint can never reach: a model that genuinely glows in a dark room.

How does it work?

The logic is actually simple; the real care goes into the execution. A tiny LED (usually a pico/0402 or 0603 SMD LED, or light piped through fibre optic) is hidden inside the model or its base. It's then wired with fine enamel wire to a power source, which can be a button cell, USB, or a circuit built into the base.

The light escapes through channels, holes or clear parts you prepare in advance. For that escaping light to look convincing, you have to solve two things at once.

• Light management: light should leave only where you want it. Light that escapes elsewhere (a light leak) ruins the model. To stop that, you trap the light inside by painting the interior black and lining it with foil.
• Working with the paint: a bare LED can look harsh and artificial on its own. So you add a painted OSL halo around the exit point, which gives you a smooth, consistent transition both in photos and in the dark.

How do you do it, step by step?

The most important thing to keep in mind: nearly all of this happens before assembly. Once the model is sealed, you can't reach inside to fix anything. The order goes like this.

1. Plan. Where does the light exit? Where does the LED hide? What path do the wire and power take down to the base? Answer these before you glue any parts.
2. Cut the channels. Open space or channels for the LED and wire with a drill and a hobby knife. If you need a clear exit, prepare clear resin or fibre optic now.
3. Place and solder the LED. Once it's positioned, wire the LED to power with fine wire and always through a resistor. Run an LED without one and it burns out.
4. Seal the light. Paint the interior black or line it with foil. The goal is simple: light should show only at your chosen exit point.
5. Test. Power it up before you close the model. Is the exit right, is there a leak, does the joint hold? Find out now.
6. Paint and add OSL. Paint the model normally. Then add a painted OSL halo around the light exit so the real and painted light blend together.
7. Integrate the power. Finally, hide the cell, switch or USB port in the base. That way the base becomes both the scene and a secret circuit box.

Which materials and tools do you need?

You'll notice this list isn't what a painter is used to, because half of it comes from the electronics shop.

• A tiny SMD LED (pico/0402/0603) or fibre optic cable.
• Fine enamel/solder wire and a resistor matched to the LED (essential to protect it).
• A soldering iron, a small drill and a hobby knife.
• Clear resin or a ready-made clear part for the light exit; it helps both with the glow and with gloss.
• For power: a button cell, USB, or an in-base circuit with a switch.
• For light sealing: black paint and aluminium foil.

When you're working with clear exits and glossy surfaces, knowing water effects and painting gems & lenses makes the job far easier, because light reads as far more believable when it comes off a clean, glossy face.

The most common mistakes

The errors that break source lighting look small one by one. But they're costly precisely because most of them surface only after the model is sealed.

• Light leak: this is the most destructive mistake. Light escapes where you don't want it and kills the illusion, so you have to seal the interior properly.
• Wiring the LED with no resistor: here the LED either burns out instantly or has its life badly cut short. In other words, the resistor isn't negotiable.
• Not testing after assembly: once the model is closed, access is gone. If there's a fault, it means stripping the model back down.
• Failing to hide the wire: this is usually a planning gap. The wire's route should be mapped from the very start.
• Trusting the LED alone: bare LED light without a painted OSL halo looks harsh and artificial.

Pro tips

Experienced builders treat this less like an electronics project and more like a tight assembly sequence. That's because once the order is right, the rest follows on its own.

Plan first, mount second. Solving the LED and wire route before you glue anything is the single most critical step in source lighting, because everything else is built on that decision.

• Always use the real LED and a painted OSL halo together; the most convincing result comes exactly where those two meet.
• Test, test, then test again. Check the light at every stage, because fixing a fault inside a sealed model is next to impossible.
• Put real effort into light sealing. A black interior and foil look like dull work, but the success of source lighting comes down directly to preventing leaks.
• Start simple: light one lens or reactor with a single LED. Move on to complex multi-LED setups only after that foundation is solid.
• Hide the power and circuit in the base; basing techniques set the scene and conceal the cell at the same time.

Frequently Asked Questions

What's the difference between LED source lighting and OSL?

Both describe illumination, but their methods are opposite. OSL fakes light with paint; on a flat model you brush in the illusion of illumination. LED source lighting, on the other hand, puts a real light source in the model, so light physically exits. The best result combines both: the LED gives the glowing core and a painted OSL halo softens the transition.

Can a beginner do this?

Let's be honest: source lighting is an advanced technique, and alongside modelling it needs basic electronics (LED, resistor, soldering). Even so, you can start with a simple single-LED project, say lighting one lens. The healthiest path is to get comfortable with brush technique and OSL first, then move on to electronics.

Why can't an LED be wired without a resistor?

The reason is that LEDs are sensitive to current. Wired straight to power without a suitable resistor, an LED draws too much current and either burns out instantly or has its life badly shortened. A resistor keeps the current at a safe level, which is why it isn't optional in the circuit; it's a required part.

How do I prevent light leaks?

A light leak is simply light escaping where you don't want it, and it easily ruins the model. The fix is to make the interior light-tight by painting the inner surfaces black and, if needed, lining them with aluminium foil. Then light shows only at the exit you cut, and the illusion stays clean.

Which LED should I use?

At miniature scale you usually want tiny SMD LEDs, because pico, 0402 or 0603 sizes are small enough to hide inside the model. For harder-to-reach points, piping light through fibre optic is also common. When choosing, make sure of two things: the LED fits inside the model, and its colour suits the scene.

Where do I hide the power?

The most practical place for it is the base. A button cell, switch or USB port tucks inside it, so the base becomes both the diorama's scene and the circuit box. The one catch is that you must plan the wire's route down from the model to the base from the start, or the wire ends up exposed and breaks the illusion.

Would I use this on a gaming army?

Usually not. Source lighting is fragile, time-consuming and costly, so it isn't suited to minis carried around a gaming table. Its real home is display models, dioramas and competition or showcase pieces. There, a detail that genuinely lights up leaves an impression no painting technique can match.

The key takeaway

In the end, source lighting has one golden rule: plan first, mount second, and test at every step. Solve the light path and leak sealing before the model closes, and everything else falls into place on its own. Finally, combine the real LED with a painted OSL halo; a glowing core plus a soft transition together give the most convincing result.

Before you take this on, a solid brush foundation and the right kit make it far easier. The gloss that brings lenses and clear exits to life, plus everything you need for clean painting, the paints, brushes & hobby supplies are waiting for you at Terminal Wargaming.