======================= Color vision simulation ======================= The simulator in the :doc:`Accessibility Inspector <../index>` in Firefox Developer Tools lets you see what a web page would look like to users with various forms of *color vision deficiency* (better known as "color blindness"), as well as *contrast sensitivity loss*. "Color blindness" is a bit of a misnomer, since most people with these disorders can see colors, but do not see all of the distinctions that people with normal color vision can see; color vision deficiencies affect perception across the color spectrum, not only of specific colors like red or green. Color vision deficiencies affect about 8% of men, and 0.5% of women. The most common forms of color blindness (commonly lumped together as "red-green color blindness") affect more men than women, because they are due to a mutation in a gene in the X chromosome, which men usually have only one copy of. Contrast sensitivity loss can be caused by cataracts, glaucoma, diabetic retinopathy, and other disorders of the retina; it can be age-related, congenital, or due to an injury. .. note:: This feature depends on webrender, an experimental featurethat is not enabled by default on all platforms. You can force-enablewebrender by settingthe preference ``gfx.webrender.all`` to ``true`` using the `Firefox Configuration Editor `_ (note that if webrender is enabled by default on your platform, the setting has no effect. The current color simulation option may be selected from the **Simulate** menu as shown. .. image:: accessibily_color_simulation_menu.jpg :alt: Simulate menu in Accessibility panel. Used for selecting the simulation mode: None, Protanopia (no red), Deuteranopia (no green), Tritanopia (no blue), Achromatopsia (no color), Contrast loss :class: center The following table shows a colorful image of a cat's face, and what it looks like in the each of the simulations. .. |image1| image:: 28369550088_617db0d6f2_m.jpg :alt: Colorful image of a cat's face, without modification .. |image2| image:: colorcat_protanopia.png :alt: Colorful image of a cat's face, with protanopia simulation .. |image3| image:: colorcat_deuteranopia.png :alt: Colorful image of a cat's face, with deuteranopia simulation .. |image4| image:: colorcat_tritanopia.png :alt: Colorful image of a cat's face, with tritanopia simulation .. |image5| image:: colorcat_achromatopsia.png :alt: Colorful image of a cat's face, with achromatopsia simulation .. |image6| image:: colorcat_contrastloss.png :alt: Colorful image of a cat's face, with contrast loss simulation .. list-table:: :widths: 50 50 :header-rows: 1 * - Simulation - Image displayed * - None (Choose this to return to normal display) - |image1| * - Protanopia (no red) - |image2| * - Deuteranopia (no green) - |image3| * - Tritanopia (no blue) - |image4| * - Achromatopsia (no color) - |image5| * - Contrast loss - |image6| .. note:: The simulation transformation matrices are based on the paper: `A Physiologically-based Model for Simulation of Color Vision Deficiency `_, Gustavo M. Machado, Manuel M. OliveiraLeandro A. F. Fernandes, IEEE Transactions on Visualization and Computer Graphics, Volume 15 (2009). .. note:: Firefox 81 removed unnecessary simulations for *protanomaly*, *deuteranomaly*, and *tritanomaly*, and added a simulation for *achromatopsia* (no color). See also ******** - `Types of color blindness `_ - `Color blindness simulator `_ - `Contrast sensitivity `_ - `Color palettes for color blindness `_ - `Color universal design `_ - `WCAG success criterion 1.4.1: Use of color `_ - `WCAG success criterion 1.4.11: Non-text contrast `_