Shadows, Lighting, and Spatial Depth
Consistent shadow direction and logical light behavior are what make a composite look like a place rather than a collection of cut-out images.
Why this is the hardest part
Every element in a composited image arrived from a different source with different lighting conditions. Your job is to make them appear as if they share the same sun, the same sky, and the same spatial context. This requires establishing the light direction at the start, building all shadow work to that direction, and systematically correcting the color temperature and tonal range of every element to match the overall scene. Compositing errors from lighting inconsistency are subtle but pervasive — they are why images that contain technically accurate elements still "feel off."
Establishing your light model
Before placing any entourage or building any shadows, determine:
- Sun angle — the horizontal direction the sun is coming from (northeast, southwest, etc.). This determines shadow direction for every object in the scene.
- Sun elevation — how high the sun is above the horizon. High sun = short sharp shadows; low sun = long softer shadows. This should match the Lumion lighting settings for images that combine Lumion and Photoshop elements.
- Sky quality — overcast (diffuse light, soft shadows) vs. clear (directional light, hard shadows). Your shadow edge hardness and overall contrast should be consistent with the sky condition.
Write these down before you start. Every shadow you add, every entourage element you rotate, every overlay layer you paint should be consistent with this model.
Shadow types
| Shadow type | What it is | How to create it |
|---|---|---|
| Cast shadow | The shadow an object projects onto an adjacent surface when the sun is blocked | Duplicate-and-distort method (Card 12) for sharp objects; soft brush on Multiply overlay for organic/diffuse shadows |
| Self shadow | The shaded side of a three-dimensional object facing away from the light | Controlled by the source image of the element; adjust with a Curves or Hue/Saturation adjustment clipped to the element layer |
| Ambient occlusion | The subtle darkening where surfaces meet, intersect, or are enclosed — the shadow in the corner of a wall and floor, the shadow under a bench | Painted on a Multiply overlay layer using a small, low-opacity brush; critically important for making placed objects appear to actually sit on the ground |
| Sky fill light | The secondary, cool-toned light coming from the sky that partially fills shadows | A Screen overlay layer with a very pale blue tint painted into areas that would receive sky light but not direct sun |
Color temperature and depth
Sunlight is warm (yellow-orange). Sky light and shadow fill are cool (blue-violet). This warm/cool contrast is what gives outdoor scenes their characteristic lighting quality. In a Photoshop composite:
- Sunlit areas should have a warm tint — use a Photo Filter (Warming 85) or a yellow-orange Curves nudge on a clipped adjustment layer
- Shadow areas should have a cool tint — use a Photo Filter (Cooling 80) or a blue-violet Curves nudge in the shadow region
- Atmospheric recession makes background elements cooler and lighter — use Hue/Saturation to reduce saturation and a Screen overlay to lighten distant layers
What breaks
Shadows in different directions — the single most visible compositing error. If the Lumion image has a northeast sun and you add a Photoshop-rendered tree with a southwest cast shadow, every viewer will perceive something is wrong even if they can't articulate it. Establish one sun direction. Maintain it for every element.
No ambient occlusion under placed objects — a person, bench, or tree with no shadow directly beneath them appears to hover just above the ground. Even a minimal dark smudge on a Multiply layer directly under every placed object is enough to ground it in the scene.