What Color Is This?

I'm colorblind. This is the question everyone asks me when they find out.

So I built an app that answers it. Point your camera at anything (a dress, a paint swatch, a sunset) and get the color's name instantly. It matches against 30,000 named colors using CIEDE2000 perceptual distance, which means the results actually correspond to how humans see color, not just how computers store it.

whatcoloristhis.one · whatcoloristhat.one · Google Play

What you get

Every color gets three tiers of identification:

• Family: the broad category (red, blue, teal, gray)
• Descriptor: a qualified label ("light muted blue", "vivid orange", "very dark gray")
• Named match: the closest of 30,000 named colors, ranked by perceptual distance

Features

• Camera sampling with 7x7 pixel averaging and white balance calibration
• Image upload: drop a photo, tap anywhere to sample
• Color matches: complementary, analogous, triadic, split-complementary
• Accessible palettes: colorblind-safe swatches (Wong 2011), high-contrast pairs, CVD simulation (protanopia, deuteranopia, tritanopia via Brettel 1997)
• Personal vision settings: set your color vision type for personalized results
• Save and label: build a personal color library with notes, exportable as JSON
• Random colors: browse 30,000 named colors one at a time
• Installable PWA: works offline, add to home screen on any device

API

POST /api/match        {"hex": "#C93F38"}
GET  /api/match/C93F38

Returns family, descriptor, top 5 named matches with CIEDE2000 distance, and color harmonies.

POST /api/accessible   {"hex": "#C93F38", "cvd_type": "deuteranopia"}

Returns CVD simulations, universal-safe palette, high-contrast pairs. Optional cvd_type personalizes the response.

GET  /api/random

Random named color with descriptor and family.

Architecture

The frontend is a single HTML file on purpose: zero build tools, one request, trivial to cache offline. The Python backend has no dependencies beyond Flask.

Run locally

pip install flask flask-cors
python api.py

Runs on port 5010. You'll need the color database — grab colornames.json (29,956 named colors, each {"name": "...", "hex": "#RRGGBB"}) and place it in the project root.

Color math

All color matching is pure Python with no external dependencies:

• sRGB to linear RGB to XYZ (D65) to CIELAB
• CIEDE2000 for perceptual distance (Sharma, Wu, Dalal 2005)
• Brettel 1997 CVD simulation via LMS cone response matrices
• HSL-based color family classification with lightness/saturation modifiers

Privacy

No accounts, no tracking, no data collection. Camera and photo access is local only. Saved colors stay in your browser's localStorage. The web version uses GoatCounter (privacy-focused, no cookies). Full policy at whatcoloristhis.one/privacy.html.

License

MIT. See LICENSE.

Author

Luke Steuber · lukesteuber.com · Bluesky · More projects