or Pantone Matching System (PMS) - is a database of over 2000 colors, introduced in 1962, that follow a 13-dimensional Color Model that uses 13 base colors to generate the target color, known as a spot color. These spot colors…

The Precision Approach Path Indicator is the system in commercial aviation that has generally been identified as the most critical use of color for commercial pilots. The system uses red and white lights on the ground to inform the pilot…

Paralogs are a set of genes in the same species that descend from the same common gene, but split apart during a duplication even. The LWS and MWS genes in primates are paralogs. that have evolved by duplication and code…

a family of "pale" colors, which, when described in the HSV Color Space, have high Value and low Saturation.

One of the resulting parameters from the Color Blind Check app, the PDT score (abbreviated from Protan-Deutan-Tritan) shows probability (out of ten) that the individual has each type of CVD. For example: A certain Deutan has a PDT score of…

The maximum of a Photoreceptor's Absorption Spectrum, i.e. the wavelength of light to which they are the most sensitive. Opsins are generally defined by their Peak Sensitivity. For example, the human visual opsin peak sensitivities are in the following table.…

A Polychromatic color vision system that is 5-dimensional (generally, having 5 different types of Cones). Pigeons are a possible example of a Pentachromatic animal. Human females that are Heterozygous for both their L and M opsins (i.e. simultaneously expressing genes…

A phenotype is the physical/observable expression of a gene. In the context of color vision, the Phenotype is the "symptom", i.e. the measurable defect, such as a Tritan defect. Each phenotype can generally be linked to several genotypes. For red-green…

A special type of Fluorescence, where the absorption and emission of light do not happen simultaneously (in very short time scales), but where the pigment emits light for a long time after absorption. The best example of this is glow-in-the-dark…

Red light therapy (or Low Level Laser Therapy) that exposes the retina to near-infrared or infrared light in the range of 650-1100nm. The red light 'reactivates' aged mitochondria in the Ellipsoids of Photoreceptors, which improves Color Contrast Sensitivity. However, the…

Oversaturation of the Photoreceptors (opsins). Since the Rods are much more sensitive to light, they are useful in low-light conditions. However, in bright light, they are overwhelmed by photons and are essentially 'saturated' with light and therefore go 'inactive'. When…

When measuring the brightness of light, there are two parallel systems of quantities that can be used: Photometric (Luminous) quantities - measures related to the perceived brightness of lightRadiometric quantities - measures related to the absolute physical brightness of light…

A material that can exhibit Structural Color by having periodic changes in refractive index. This type of structural color is responsible for the iridescence of opals and butterfly wings. There are also many manmade applications of photonic crystals.

Abnormal sensitivity to and/or discomfort from light. A common symptom of Achromatopsia.

Photopic Vision is optimized for bright environments, generally enabled by Cone Cells in vertebrates. With Scotopic Vision, they make up both halves of the Duplex Retina. Photopic Vision is usually used at daytime by humans, though also functions at night…

Opsins of Cone cells. In humans, the L-, M- & S-Opsins are the Photopsins.

A cell in the retina that is sensitive to light due to the presence of Opsins. The first stage of the Phototransduction Pathway.

is the ability of organisms to move directionally in response to a light source. Even organisms as simple as bacteria exhibit phototaxis, and therefore can be described as having 'sight'. Phototaxis is often used to test the behavior of some…

The cascade of a visual signal from the photon to the perceived color. The pathway is often described as the chain of cells that the signal travels through on its way to the brain: Photoreceptor Cell - Rods and ConesHorizontal…

A model of how organisms are related by their evolutionary history, based on the fact that all living things are related by common descent. Phylogeny is based on paleontology, comparative anatomy, and genetic analysis. The main product of phylogenetics is…

A popular manufacturer of Color Correction Lenses. Pilestone glasses are much cheaper than EnChroma glasses, but they work in a fundamentally different way. Instead of employing a Notch Filter, they comprise a color tint that can be effective at boosting…

A tiny Micronesian island atoll with a population of 250 people, famous for its high prevalence of Achromatopsia. The island was the main setting of the very popular non-fiction book by Oliver Sacks: Island of the Colorblind. Its prevalence on…

A ciliary opsin, which is the closest phylogenetic relative to the vertebrate visual opsins (the Rhodopsin and Photopsins in your retina). Pinopsin is a blue-light sensitive opsin similar to Rhodopsin and has been found in the pituitary glands of birds,…

The category that includes all visual systems able to perceive color (Dichromacy, Trichromacy, Tetrachromacy, etc.) and excludes visual system unable to perceive color (Achromacy/Achromatopsia and Monochromacy)

A dichromacy-trichromacy hybrid that defines the color system of most new-world monkeys. While most mammals have dichromatic color vision, diurnal primates have mostly evolved a form of trichromacy: Old world apes (e.g. humans) evolved a 'true' form of Trichromacy where…