How Color Science Can Reduce Visual Fatigue for Logistics Operators: A B‑End UI Study

Project Background

Front‑line logistics staff (customer‑service agents and warehouse workers) perform high‑intensity, repetitive tasks that require prolonged screen use. Users reported visual fatigue, eye strain and reduced efficiency, and existing B‑end color standards and accessibility guidelines (focused on C‑end users) do not address these issues.

Research Process

Industry standards – Reviewed current B‑end color specifications and found no mature solutions for visual fatigue.

Competitive analysis – Conducted horizontal analysis of 20 reading/education apps and vertical analysis of native eye‑care modes on Windows, macOS, iOS, Android, MIUI and HarmonyOS.

Theoretical basis – Summarized academic findings on eye‑movement metrics, pupil size, heart‑rate and subjective assessments. Key factors identified: contrast ratio (AA ≥ 4.5:1, AAA ≥ 7:1), saturation, brightness, ambient lighting, and screen color temperature.

Key Findings

Current UI contrast (~21:1) is excessively high and causes visual fatigue.

Medium‑saturation gray, green and yellow backgrounds minimise eye strain.

Optimal ambient lighting: 5000 K color temperature, 2000 lx illumination; screen brightness around 100 cd/m².

Design Goals

Create three eye‑care color schemes (gray, green, yellow) for the customer‑service workbench that preserve readability and operational efficiency while reducing visual fatigue.

Solution Design

Adjusted the original brand colors by adding a 15 % green overlay. Generated graded color steps by overlaying 10 % opacity layers of #FFFFFF and #000000 on the base brand color, producing brand‑consistent eye‑care palettes.

Validation Experiments

Participants – 10 internal staff (design, product, R&D, business) and 2 frontline agents.

Groups – Tested under three lighting conditions: normal daylight, post‑work fatigue (late afternoon) and night (no external light).

Procedure – Each participant viewed four designs (white, gray, yellow, green) for 5 minutes while wearing an eye‑tracker, followed by 2‑3 minute breaks and a subjective questionnaire. Collected metrics: fixation count, fixation duration, pupil diameter, heart‑rate, and self‑reported fatigue.

Results – Gray, green and yellow schemes produced lower fixation dispersion, smaller and more stable pupil sizes, and reduced heart‑rate variability compared with the white baseline. Subjective scores confirmed lower perceived fatigue; gray was preferred by 45 % of users.

Implementation

Integrated the three eye‑care palettes into the JD Logistics UI framework (LUI 3.0), encoding 29 base colors with eye‑care variants and adding a one‑click theme switcher.

Gray theme launched early 2025.

Green and yellow themes fully deployed by May 2025.

Adoption reached 35 % nationwide, with measurable improvements in visual comfort across regions.

Impact and Future Work

The eye‑care mode has been extended to other JD Logistics B‑end systems, including warehouse‑management PC and handheld applications and domestic merchant workbenches. Plans are to roll out the feature to all logistics applications by 2026, with ongoing monitoring and palette refinement based on user feedback and physiological data.