In color science, a color gradient specifies a range of position-dependent colors, usually used to fill a region. Name A color gradient is also known as a color ramp or a color progression. In assigning colors to a set of values, a gradient is a continuous colormap, a type of color scheme. In computer graphics, the term swatch has come to mean a palette of active colors. Definitions Color gradient is a set of colors arranged in a linear order ( ordered) A continuous colormap is a curve through a colorspace Strict definition A colormap is a function which associate a real value r with point c in color space which is defined by: a colorspace C an increasing sequence of sampling points a series of values in the colorspace the mapping a rule for interpolating the intermediate values where: r is a real number is a set of real numbers c is a color = point in colorspace C Types Criteria for classification: dimension discrete ( clasessed ) / continuous shape range: full or limited. Example : pastel color with limited range of saturation. perceptual uniformity order ordered (sequential) and non-ordered (categorical) perceptual order readability for color-vision deficient or color-blind people ( colorblind-friendly) color space color depth Dimension 1D 2D 3D Shapes Axial gradients An axial color gradient (sometimes also called a linear color gradient) is specified by two points, and a color at each point. The colors along the line through those points are calculated using linear interpolation, then extended perpendicular to that line. In digital imaging systems, colors are typically interpolated in an RGB color space, often using gamma compressed RGB color values, as opposed to linear. CSS and SVG both support linear gradients. Radial gradients A radial gradient is specified as a circle that has one color at the edge and another at the center. Colors are calculated by linear interpolation based on distance from the center. This can be used to approximate the diffuse reflection of light from a point source by a sphere. Both CSS and SVG support radial gradients. Conic gradients Conic or conical gradients are gradients with color transitions rotated around a center point (rather than radiating from the center). Example conic gradients include pie charts and color wheels. Other shapes In vector graphics polygon meshes can be used, e.g., Adobe Illustrator supported gradient meshes. color space Effect of color space The