Lighting Basics: Highlights and Shadows

Technical Breakdown: Highlights and Shadows in Digital Art

1. Light Source & Direction
   All highlights and shadows are based on the position, intensity, and direction of the light source. Understanding whether the light is hard (like the sun) or soft (like diffused daylight) affects edge sharpness and shadow falloff.

   
   

2. Highlight Placement
   Highlights appear on the surfaces facing the light source directly. The strongest highlights are typically on glossy or reflective surfaces, but even matte materials show a soft transition toward the lit side.

   Important: highlight values should never exceed the value of the light source to maintain physical believability.

   
   

3. Shadow Structure
   Shadows consist of two main types:

   Form shadow: the natural shadow on the object itself, due to its shape curving away from the light;

   Cast shadow: the shadow an object throws onto another surface.

   Both should follow the shape and angle of the light. Cast shadows sharpen when close to the object and blur with distance (penumbra effect).

   
   

4. Core Shadow & Terminator Line
   On rounded forms, the core shadow lies between the lit area and the reflected light. The terminator is the soft edge where light turns into shadow, controlling this transition is key to realistic rendering.

   
   

5. Value & Falloff Control
   Good lighting uses controlled falloff: highlights fade smoothly, and shadows deepen gradually. Avoid harsh transitions unless using hard light. Use tools like gradient masks, soft brushes, or luminance selections to control this accurately.

   
   

6. Reflected Light
   In shadows, soft bounced light from nearby surfaces should be subtly added to avoid shadows looking flat. Reflected light is never brighter than direct light and should respect local color influence.

   
   

7. Surface Material Impact
   Different materials react to light differently:

   Matte: soft, diffused highlights and shadows;

   Glossy: tight, sharp highlights with clearer light falloff;

   Transparent: light passes through, creating complex internal highlights and caustics.

   
   

8. Color in Light and Shadow
   Shadows are not just darker, they often carry ambient tones. Warm light creates cool shadows and vice versa. Use subtle hue shifts for realism.