Color Grammar in the HMI

One disciplined, colorblind-safe color system across every operator surface so a color always means the same thing and alerts are never lost.

One color system, enforced everywhere

Color is the fastest channel to an operator's brain and the easiest to abuse. Kronos enforces a single color grammar across the 3D twin overlay, SCADA/HMI, dashboards, and mobile views so that a hue never carries two meanings. The reserved alert palette is used for nothing except alerts, so an alarm can never be camouflaged by decorative color elsewhere on the screen.

Domain palettes

• Thermal fields (wall temperature, reactor/DEC heat): orange ramp
• Structural and magnet (REBCO strain at 16.84 T / 26.49 T): gray-blue ramp
• Plasma / flux surfaces: dedicated flux palette
• Operations and ecosystem status: green family
• Feedback, alerts, and retraining signals: reserved pink/alert palette

These map to the same color grammar used throughout the Kronos architecture, so an engineer moving between the AI-native documentation, the twin, and the live control room reads color consistently. A scalar field is always shown with a perceptually uniform ramp so equal color steps mean equal physical steps, and a divergent quantity (error, margin) uses a divergent ramp centered on its neutral value.

Colorblind-safe by construction

Because roughly one in twelve men has a color-vision deficiency, color is never the sole carrier of meaning. Every color distinction is backed by a redundant cue — shape, position, hatching, or a label — so the interface remains fully usable in grayscale. This is verified by simulating common CVD types over every screen; see accessibility and colorblind-safe design. Confidence hatching on the twin overlay is a deliberate example: it encodes uncertainty by texture, independent of color.

The grammar is also theme- and lighting-aware, staying legible as control-room lighting shifts across shifts. It underpins the whole visual system — see cognitive load and the 3D twin overlay.