Project Atlas - Color Vocabulary and Mechanism Taxonomy

Purpose

Establish a controlled vocabulary so every Atlas document uses the same meanings for color-related terms.

Five Layers

1. Physical variables
2. Perceptual variables
3. Cognitive mechanisms
4. Communication functions
5. Measurement methods

Physical Variables

• Spectral power distribution
• Reflectance
• Illuminant
• Medium

Perceptual Variables

• Hue
• Lightness
• Brightness
• Chroma
• Saturation
• Colorfulness

Contrast Types

Never use 'contrast' by itself. Specify:

• Luminance contrast
• Hue contrast
• Chroma contrast
• Saturation contrast
• Simultaneous contrast
• Local contrast
• Global contrast
• Semantic contrast
• Structural contrast
• Temporal contrast
• Motion contrast

Cognitive Mechanisms

• Attention
• Recognition
• Grouping
• Segmentation
• Memory
• Prediction
• Decision making
• Emotion
• Meaning

Communication Functions

• Priority
• Status
• Relationship
• Navigation
• Identity
• Warning
• Affordance
• Category
• Quantity
• Sequence

Working Definitions

Accent

An element whose perceptual distinctiveness is sufficient to reliably attract attention for the current task.

Hierarchy

The ordered probability that observers attend to elements.

Harmony

A subjective judgment emerging from multiple interacting variables rather than hue geometry alone.

Palette

A constrained system of interacting colors, not independent swatches.

Research Tracks

1. Luminance vs chromatic contrast
2. Harmony across disciplines
3. Painter knowledge vs laboratory evidence
4. Architecture and large-field color
5. Accessibility and low vision
6. Film and temporal color
7. Branding and semantic meaning

Next Major Research

Compare historical color theorists and artists (Chevreul, Albers, Itten, Munsell, Kandinsky, Gurney) against modern vision science to identify:

• Observations that remain valid
• Mechanisms now understood
• Claims requiring revision
• Open questions