Color Science
Covert Recon Mode Validation
Color Palette — Live Calculations
WCAG 2.2 Contrast Matrix
All foreground/background pair contrast ratios. AA normal ≥ 4.5:1, AA large ≥ 3:1, AAA normal ≥ 7:1, AAA large ≥ 4.5:1.
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Scotopic Vision Science
Why Red Light Preserves Dark Adaptation
Human scotopic (dark-adapted) vision is mediated by rhodopsin, a photopigment in rod cells with peak sensitivity near 507 nm (blue-green). Red light in the 620–700 nm range falls at the extreme low end of rhodopsin’s absorption curve, meaning rod cells are nearly insensitive to it. This allows operators to read instruments and displays without bleaching rhodopsin, preserving the ability to detect dim targets in peripheral vision.
MIL-STD-1472H — Human Engineering
Section 5.5.3.6 establishes requirements for dark adaptation and night vision conditions, specifying that ambient illumination shall be controllable and compatible with dark-adapted operations. Section 5.5.3.6.3 defers NVIS-compatible lighting requirements to MIL-STD-3009. This is the primary standard governing human-system interface design for U.S. Department of Defense systems (September 2020). The archived reference PDF (MIL-STD-1472G.pdf) contains the H revision.
MIL-STD-3009 — NVIS Compatibility
MIL-STD-3009 governs lighting and display compatibility with Night Vision Imaging Systems (NVIS). It defines spectral radiance limits to prevent cockpit/vehicle lighting from overwhelming image intensifier tubes. While primarily an aviation and vehicle standard, its spectral requirements inform any display intended for use in light-controlled environments.
Honest Limitation
Consumer LCD and OLED displays cannot produce monochromatic 630 nm red. They use broadband RGB subpixels, meaning even a “pure red” hex value (#cc2020) produces a spectral power distribution that includes some energy outside the 620–700 nm band. True MIL-STD-3009 compliance requires narrow-band optical filters or dedicated NVIS-compatible displays. The Covert Recon Mode palette is designed to approximate the intent of these standards on consumer hardware — it is not a substitute for dedicated tactical lighting equipment.
Standards Citations
- MIL-STD-1472H — Department of Defense Design Criteria Standard: Human Engineering (September 2020). Section 5.5.3.6: Dark adaptation and night vision conditions.
- MIL-STD-3009 — Lighting, Aircraft, Night Vision Imaging System (NVIS) Compatible. Spectral radiance limits for NVIS-compatible displays.
- CIE 1951 Scotopic Luminosity Function V′(λ) — Commission Internationale de l’Éclairage. Standard observer for scotopic (rod-mediated) vision, peak at 507 nm.
- WCAG 2.2 Contrast Requirements — W3C Web Content Accessibility Guidelines. Success Criteria 1.4.3 (AA) and 1.4.6 (AAA) for text contrast ratios.
- ISO 9241-3 — Ergonomic requirements for office work with visual display terminals. Display ergonomics including luminance contrast and color requirements.