Summary
Colour theory is the study of how colours are created, how they relate to each other, and how they affect the viewer. For game artists it provides a structured vocabulary for choosing palettes, designing UI, and directing attention. The fundamentals — the three components of colour, the colour wheel, and a handful of named harmonies — are shared with classical painting, illustration, and film, and transfer directly into both 2D and 3D game art.
Key ideas
The three components of colour
- Hue — the base colour (red, green, blue, yellow, and so on). What we usually mean by “colour” in casual speech.
- Saturation — the intensity or purity of a hue. Highly saturated colours feel vivid; desaturated colours feel neutral or muted.
- Lightness (Value) — how dark or bright the colour is. Value is what governs shape readability and plane separation (see composition-and-tonality).
Each component does a different communication job, and adjusting only one at a time is often the most controllable way to change a scene.
The colour wheel
Credited by Sharov to the Swiss artist Johannes Itten (The Art of Color, early 20th century). The wheel arranges hues in a circle so that positional relationships correspond to perceptual relationships. Four harmony families:
- Complementary — colours on opposite sides of the wheel (e.g. red/green, blue/orange). Maximum contrast; attracts attention; the classic “warm accent against cool background” pattern.
- Analogous — colours adjacent on the wheel (e.g. yellow → orange → red). Low-contrast, harmonious, useful for unified moods such as the warm atmosphere of Firewatch.
- Split-complementary — one base colour and the two colours adjacent to its complement. Retains strong contrast while softening the clash of a direct complementary pair.
- Monochromatic — a single hue varied only in saturation and value. Reads as calm and unified; common in stylised or limited-palette work.
Colour psychology in games
- UI colour coding — historical conventions use blue or green for allies and red for enemies so that friend and foe can be distinguished at a glance.
- Resource bars — red for health (blood, vitality) and blue/violet for mana (magic, the unknown) — as in Diablo IV.
- Environment cues — red environments raise tension and prepare the player for action or fear; yellow is often used to mark interactable objects; calm greens and blues suggest safety or rest.
- Scene shifts — the same geometry can swing between threatening and peaceful by shifting hue dominance between red/purple and green/blue.
Realism versus stylisation
- Realism tends to a neutral, cooler, lower-saturation palette with subtle accent colours. Small mistakes are punished because the audience has a lifetime of reality to compare against.
- Stylisation uses bold, saturated accents and simplified shapes. Games like Fortnite and Overwatch use colours that do not exist in nature without the audience rejecting them, because the stylised contract permits it.
- The choice is driven by art direction and target audience, not by preference. A project cannot meaningfully use both modes in the same location without careful justification.
In practice
Unity specifics:
- Author materials in linear colour space (Project Settings → Player → Color Space → Linear) so that HSV operations and lighting compose correctly.
- Use Volumes → Colour Adjustments → Hue Shift / Saturation / Contrast to prototype palette changes non-destructively before committing to texture rework.
- Shader Graph exposes Hue/Saturation/Value nodes for per-material or per-object recolouring (see shader-graph-overview).
- For UI, prefer a palette ScriptableObject that centralises ally/enemy/neutral/interactable colours so that conventions stay consistent across screens and can be adjusted once for accessibility.
- Accessibility: red/green complementary pairs fail for the most common colour-vision deficiencies. Pair hue differences with value and shape differences so the signal survives desaturation.
For pixel art specifically, see the deeper treatment in pixel-art-colour-theory (hue shifting, three-shade system, limited palettes, dithering).
Evidence
“Hue is essentially a base color; Saturation is the intensity or purity of color and Lightness (Value) is the darkness or brightness of a color, which determines its shape and depth.” (Sharov, Using Light and Color in Game Development, see source-light-and-color-game-dev)
“In UI/UX, we often need some kind of indication to distinguish allies from enemies, and historically, games have marked allies as blue or green and enemies as red.” (Sharov, see source-light-and-color-game-dev)
“With stylization, we work with a completely different approach, using bright colors with accents to attract as much attention as possible and to smooth out the conventions of the game.” (Sharov, see source-light-and-color-game-dev)
Implications
- A game’s palette is a design decision, not an art-pass decision. Ally/enemy/interactable colour conventions should be agreed with systems designers before UI and VFX are built on top of them.
- Harmony families are starting vocabulary, not recipes — they make it easier to explain palette choices to collaborators and to diagnose why a scene feels “off”.
- Colour conventions carry cultural and accessibility baggage. Red = danger is near-universal in Western games but is not culturally neutral, and red/green coding alone excludes a measurable portion of players.
Open questions
- How should palette design interact with colour-blindness and low-vision accessibility? Sharov’s article is silent on this, but it is a central concern for shipping games.
- How far do Itten’s harmony families survive in HDR colour workflows, where saturation and value ranges are extended beyond what the wheel was drawn for?
- What is the best authoring workflow for consistent palettes across 2D sprites, 3D materials, lighting, and UI in a single Unity project?