The Farnsworth D-15 is an Arrangement Test where an individual must arrange 15 colored tiles that form a gradient between two colors. This is a very common test for diagnosing Color Vision Deficiency. It is also considered easier to pass…

A Standard Illuminant that is used to mimic normal daylight and is approximately white. Since Illuminants affect the perception of an object's color, most colorblind tests (not those taken on a screen) must use a D65 Illuminant. https://youtu.be/9WDr4e8eJmc

John Dalton was the first person to scientifically investigate colorblindness. His findings were published in a 1794 paper entitled "Extraordinary facts relating to the vision of colours", exploring the colorblindness of himself and his brother. He hypothesized that the vitreous…

Another name for Colorblindness. Named after John Dalton. It is the primary name for CVD in many languages (e.g. Spanish/French)

To make an image easier to read to a specific type of colorblindness. Daltonizing software can shift the colors of an image to reduce the amount of colors of confusion. Most algorithms encode the red-green information on to the blue-yellow…

A desktop utility for windows/mac/linux that will (upon pressing a hotkey) show color information of the pixel below the pointer, capture a screen area and apply a range of color filters to it. It also has a tool to highlight…

A type of Color Task, where an individual must identify a color, generally by its name, or some other absolute identifier (like Hue or RGB value). The obvious denotative color task involves communicating color verbally or in writing, such as…

The "second" type of colorblindness (after Protan; before Tritan) that acts as an umbrella term for Deuteranomaly and Deuteranopia. "Deuteran" would be the intuitive name, but this is never used. Deutan CVD is associated with the M-Cone and affects the…

The most common type of Colorblindness. It is the Deutan form of Anomalous Trichromacy. About half of all CVD is in this form. https://www.youtube.com/watch?v=3qFAtbMQqkE

A common type of Colorblindness. It is the Deutan form of Dichromacy. https://www.youtube.com/watch?v=3qFAtbMQqkE

Dichromacy is a form of color vision with two dimensions. Dichromatic humans have a Color Vision Deficiency compared to Color Normals. However, most mammals are Dichromats and have color vision very similar to Protanopes or Deuteranopes. Dichromacy is more severe…

An individual with Dichromacy.

A diffraction grating is a type of structure that produces coloration via structural color. The spacing of the diffraction grating (w in diagram below) must be about equal to the wavelength of light in the visible range (400-700nm). With that,…

A characterization of any color that equals the wavelength of monochromatic (spectral) light that evokes an identical perception of hue. A desaturated red-orange color and how its Dominant Wavelength is determined.

A photoreceptor that comprises two parallel, connected cones. They are present in all classes of vertebrates except placental mammals. The function of the double cone is not well known, but they are believed to not contribute to color vision, but…

A duplex retina describes a retina that consists of both Rod cells and Cone cells and has separate (but often overlapping) visual systems for Scotopic Vision (low light) and Photopic Vision (bright light). Duplex retinas therefore increase the range of…

A less common example of Pseudoisochromatic Plates. They are designed to screen for normal color vision, so are very difficult to pass (very few with even mild CVD will pass), on par with the Ishihara Test. Dvorine plate examples (hue-shifted…

An archaic name for colorblindness. In contrast to Achromatopsia (a term that is still used), Dyschromatopsia meant that some color vision still existed. It is still a common name for Colorblindness in some languages (e.g. Italian - Discromatopsia). It is…