DaltonLens 4+

Tools for color blind people

Nicolas Burrus

    • 5.0 • 2 Ratings
    • Free



DaltonLens is a utility to assist colorblind people by providing color filters and highlighting tools. It is especially useful to read color-coded charts and plots. Here are the main features:

• Show a pointer over your screen to get information about the color under the mouse pointer, including its name.

• Grab a screen region and apply color filters on top of it. They include the daltonize algorithm to transfer the color differences into channels that are easier to distinguish.

• Highlight similar colors in the region. This is especially useful for charts and plots, and it uses adaptive filters to better handle anti-aliased line plots.

What’s New

Version 2.4

New features:
• Add a HSVTransform filter with saturation boost, hue shifting and quantization.
• New help window, shown by default on startup.
• Merge the daltonize filters into a single one with a persistent setting for the deficiency kind.

UX improvements:
• Fix the color pointer overlay with small images by moving it to the controls window.
• Fix the Shift key behavior when the controls window has the focus.
• Show the perceptual distance to the two closest color names.
• Calling the global pointer while an image is already open won't close it, so the output of filters can be inspected.
• Better support of Spaces

Bug fixes:
• Fix the HSV range display in the highlight similar pixels filter.
• Fix the HSV transforms, wrongly applied in linearRGB instead of sRGB.
• Fix the RGB to LMS conversion to use the Judd-Vos correction XYZ space. No significant perceptual change, but should be more correct.

Ratings and Reviews

5.0 out of 5
2 Ratings

2 Ratings

Varenc ,


This app is perfect for helping colorblind people deal with any map/diagram that uses color to indicate a property. For example a precipiation map with 20 different shades going from green to red to indicate the appropriate level. With this app I just hit the keyboard shortcut, click the color I want to look up, and then it immediately flashes the corresponding color in the diagram's legend. Many other use cases as well! Like using the filters to help my fiance understand what being colorblind looks like...


App Privacy

The developer, Nicolas Burrus, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy.

Data Not Collected

The developer does not collect any data from this app.

Privacy practices may vary, for example, based on the features you use or your age. Learn More