Color is a limited attention budget
If every pipe, vessel, and button is saturated, color stops being a signal. Use neutral surfaces for stable context and introduce stronger contrast when a condition changes the operator's priorities.
Never rely on hue alone. Status text, geometry, icons, patterns, and sufficient luminance contrast keep information usable for more people and under poor viewing conditions.
Ask what the treatment communicates
| Treatment | Good use | Risk |
|---|---|---|
| Neutral body | Normal equipment context | Too little contrast can erase boundaries. |
| Focused accent | Selected item, mode, or active flow | Multiple unrelated meanings create confusion. |
| Alarm emphasis | Condition requiring awareness or action | Permanent saturation produces fatigue. |
| Motion | Process direction or changing state when necessary | Decorative animation distracts and can impair access. |
Sources and boundaries
KonnectSymbols is independently developed and is not endorsed by ISA, IEC, or ISO. These educational notes do not reproduce or replace current standards, project specifications, regulations, or an approved project legend.
- ISA-101 Human-Machine InterfacesInternational Society of Automation. Official publisher page for the ISA-101 series. The full standard requires publisher access.