OSL (Object Source Lighting) Technique: How to make your miniatures "glow"?

Do you want your miniatures to be eye-catching from across the room? Nothing makes an impression quite like OSL (Object Source Lighting), which is the illusion of light emitted by a model element: a power sword, plasma, a torch, or computer screens.

At Printallica, we often use this technique to give models from printallica.eu a cinematic feel. Here's how to tackle this topic to truly bring your miniatures to life.

💡 What exactly is OSL?

In short: it's painting light where it physically isn't. If your character is holding a glowing staff, the light from that staff must fall on their armor, face, and the ground.

3 Golden Rules of OSL:

1. The source must be the brightest: The lamp or sword must be almost white in the very center. Nothing on the model can be brighter than the light source itself.
2. Inverse Square Law: The further from the source, the weaker and less saturated the light.
3. Straight Line: Light travels in a straight line. If there's an armor piece between the source and the pauldron, the pauldron will remain in shadow.

🎨 How to paint it? (Step-by-step)

1. Prepare the base

Before you start OSL, paint the entire model normally, but keep it in a slightly darker tone. Light is best seen in the dark!

2. Define the "light map"

Use white paint (preferably heavily diluted or white ink) to mark the areas where the light will hit strongest. This is your base for the color. This will make the color you apply later bright and vibrant.

3. Apply color (Glazing)

Use very thin paint (glaze) or dedicated fluorescent paints. Apply thin layers to the white areas and gently extend beyond them to create a soft transition.

4. Enhance the center

Return to the very source of the light (e.g., the center of a bulb or a crack in a sword) and add a dot of pure white there. This will make the viewer's eye "believe" in the glow.

⚠️ Common mistakes (i.e., how not to ruin a model)

• Too thick paint: OSL is about subtlety. If you apply a thick layer of paint, the model will just look "smeared" with color, not illuminated.
• Ignoring texture: Light reflects differently from metal (sharp, bright points) than from fabric (soft, blurred patches).
• Too much range: If a small LED on the armor illuminates the entire legs, the model will lose realism. Less is more!

🛠️ Airbrush or brush?

• Airbrush: Ideal for creating a soft glow around the source. It's fast and gives natural transitions.
• Brush: Indispensable for precise edge highlighting that "catches" the light.

The best effects are achieved by combining both methods: a delicate mist from an airbrush as a base, and sharp lines with a brush on the edges to emphasize the details of prints from printallica.eu.