Colorblind Helper

About 1 in 12 men and 1 in 200 women have some form of color blindness (color vision deficiency). Colorblind Helper sits in your tray and labels colors anywhere on screen: in web pages, photos, charts, games, design tools and digital paintings.

What it does

• Names every colour you point at: HEX, RGB and the closest named colour (CIEDE2000).
• Descriptive mode: gives the full story of a colour in plain words ("Light muted teal", "Dark brown"), plus HSL, HSV, CMYK and contrast ratios.
• Through other eyes: shows how the colour reads for protan, deutan, tritan and achromat vision, in any combination you choose. The Vision page also shows Vincent's 1887 self-portrait (a red beard against a green ground) through each kind of colour vision.
• Your palette: every colour you copy is kept as a paint dab. Click a dab to copy it again, or export the whole palette as a .gpl file for GIMP, Krita or Inkscape.
• Live in a painting: themes come from The Starry Night, Café Terrace at Night, Irises, Sunflowers, Almond Blossom, Wheat Field with Cypresses and The Bedroom. There are also two plain studio themes, Charcoal and Linen.
  • Each palette is sampled from the canvas itself.
  • The banner shows the painting drifting slowly, with a museum-style caption.
  • The studio themes show the paintings in turn.
• Follows your brush: the overlay sticks to the cursor and lets clicks pass through it. You can also detach it and park it anywhere.
• Customise it: set opacity, size, swatch size, corner roundness and font, choose which fields to show, sample 1×1, 3×3 or 5×5 pixels, and set hotkeys by pressing the keys.
• Run at startup (off by default), lives in the tray, runs only one copy at a time, and uses about 1% of one CPU core while idle.

Install

Windows: download ColorblindHelper-Windows.exe from Releases and run it. There is no installer. SmartScreen may warn you because the exe is unsigned: choose More info → Run anyway.

macOS: download ColorblindHelper-macOS.zip, unzip it and move the app to Applications. The app is unsigned, so the first time you open it, right-click it and choose Open. Then allow Screen Recording (and Accessibility if you want global hotkeys) in System Settings → Privacy & Security, and restart the app.

From source (Python 3.10 or newer):

pip install -r requirements.txt
python main.py

Using it

Action	Global hotkey	Overlay focused
Copy HEX (and add to palette)	Ctrl+Shift+C	C
Freeze / unfreeze	Ctrl+Shift+F	Space
Follow cursor on / off	Ctrl+Shift+A	A
Descriptive mode on / off	Ctrl+Shift+D	D / double-click
Show / hide overlay	Ctrl+Shift+H	Esc (hide)

You can also right-click the tray icon or the overlay for the menu. Double-click the tray icon to open settings.

FAQ

How can a color blind person tell what color something is on screen? Run Colorblind Helper and move your mouse over it. The overlay shows the color's name (for example Crimson), a plain-language description (Vivid red), and its HEX and RGB values.

Which kinds of color blindness does it cover? It covers protanopia/protanomaly (red), deuteranopia/deuteranomaly (green, the most common), tritanopia (blue) and achromatopsia (no color). The simulations use the Machado et al. (2009) model.

Can I use it as an eyedropper or screen color picker? Yes. Freeze the color with Space or Ctrl+Shift+F, then copy the HEX or RGB value. Copied colors are kept in your palette.

Is it useful for designers checking accessibility? Yes. Descriptive mode shows WCAG contrast ratios against white and black, and the simulations show which colors would be confused.

Does it collect data? No. It runs entirely offline, with no account and no telemetry.

Alternatives & related

You might also know tools such as Color Oracle (a full-screen color blindness simulator), Sim Daltonism (macOS) and the eyedroppers built into design apps. Colorblind Helper is different because it's a follow-the-cursor color name overlay that combines identification, simulation and an artist's palette in one small app.

The paintings

All the paintings are by Vincent van Gogh (1853–1890) and are in the public domain. The scans come from Wikimedia Commons:

Painting	Year	Collection
The Starry Night	1889	Museum of Modern Art, New York
Café Terrace at Night	1888	Kröller-Müller Museum, Otterlo
Irises	1889	J. Paul Getty Museum, Los Angeles
Sunflowers	1888	National Gallery, London
Almond Blossom	1890	Van Gogh Museum, Amsterdam
Wheat Field with Cypresses	1889	Metropolitan Museum of Art, New York
The Bedroom	1888	Van Gogh Museum, Amsterdam
Self-Portrait	1887	Art Institute of Chicago

The quotes in the sidebar come from Vincent's letters to his brother Theo.

Build

pip install -r requirements.txt pyinstaller pillow
python tools/make_icons.py
python -m PyInstaller --noconfirm ColorblindHelper.spec

This produces dist/ColorblindHelper.exe on Windows and dist/ColorblindHelper.app on macOS. Publishing a GitHub release also builds both automatically (workflow). tools/prepare_paintings.py turns the full-size scans into the bundled 1400 px JPEGs.

Project layout

colorblind_helper/
  app.py              tray, menus, hotkeys, single instance, palette, wiring
  overlay.py          overlay window + renderer (shared with the live preview)
  settings_window.py  the settings window
  widgets.py          gallery banner, theme cards, toggles, palette dabs, hotkey recorder
  paintings.py        painting metadata, crops, blur, colour-vision image simulation
  themes.py           painting-derived themes, typography, canvas texture, stylesheets
  colors.py           conversions, naming, descriptions, CVD simulation
  pixel.py            screen sampling (GDI on Windows, Qt elsewhere)
  autostart.py        run at login (registry / LaunchAgent / XDG)
  settings.py         persisted settings
  hotkeys.py          global hotkeys (pynput)
  icon.py             app icon (a Starry Night crop with a colour-wheel iris)

Colour-vision simulation uses the Machado, Oliveira & Fernandes (2009) model.

License

The code is MIT licensed. The paintings are in the public domain.