Colorblind Simulator (Free and Pro) is a collection of tools to aid anyone developing materials that address the needs of those who have color vision deficiencies (CVD). The tools simulate:- images: examples, galleries, and camera- text colors with W3C contrast ratio between text color and background color- single colors for both Material Design colors (Pro only) and all true colors
The default app settings are for dichromatic vision loss. These conditions involve 100% loss of either the:
- red cones (protanopia)- green cones (deuteranopia)- blue cones (tritanopia)
To accommodate anomalous trichromacy, the Pro version of the app allows for setting the percentage of cone loss. Thus, the app can simulate protanomaly, deuteranomaly, and tritanomaly.
Simulation of CVD is based on different research models. The Pro version of the app allows the selection between four different models:
- ImageJ plugin- Brettel-Vienot-Mollon (BVM)- Meyer-Greenberg-Wolfmaier-Wickline (MGWW)- Machado-Oliveira-Fernandes (MOF)
The differences are small, but there are differences, A fifth model, the grayscale model, allows for the simulation of monochromatic vision.
We do not see RGB colors. Actually, the cones do not see color. Rather they are receptive to light photons of different wavelengths. The acronym is LMS, which stands for long (red), medium (green), and short (blue) wavelengths. The wavelength sensitivity curves for long and medium cones have a large amount of overlap, while the blue wavelengths have very little overlap with the other two. Thus, simulation involves converting RGB to LMS, applying the variables for type and percentage, and then converting back to RGB.
Color vision is a complex process involving the eye, optical nerve, and brain. The cone cells on the retina of the eye are the sensory organs, and only part of the system. This app covers two variables using three different models. There are other variables that are not managed, including the color variations between devices. The application generates the same color code, but the display of the color may vary between devices.
The gamma of the display device is important to accurate simulation. A gamma of 1.0 applies to viewing a device in bright surrounding light. A gamma of 1.25 is for viewing in dim surroundings. A gamma of 1.5 is for viewing in dark surroundings. The default value for the app is 1.0. The pro edition allow for varying the gamma between 1.0 and 1.5. A gamma value of 1.51 lets the app determine the viewing gamma based on the brightness setting of the device.
The Free version includes ads, while the Pro version does not include ads.