Glossary on color

X-Rite and Labomat bring you a Color Management Glossary that contains over 1000 color-related terms and has been written to help you better understand the impact of color on your vision and workflow . From the fundamentals of color and light to expressions related to printing and industry, this glossary is very rich. Search for the term you are interested in below for its definition.

Encapsulated PostScript (EPS)

A metafile format developed by Adobe that supports both images and graphics based on bitmap or vector objects. This file format is supported by various applications and is frequently used to transfer files between applications. Compatible with RGB, CMYK and LAB color spaces, it is also often used to transmit files from one application to another and for color separation tasks.

Encryption

A method of encoding a file by means of software programs so that no one can access its content.

Encapsulated PostScript (EPS)

A metafile format developed by Adobe® that supports both images and graphics based on bitmap or vector objects. This file format is supported by various applications and is frequently used to transfer files between applications. Compatible with RGB, CMYK and LAB color spaces, it is also often used to transmit files from one application to another and for color separation tasks.

Error diffusion

Printing technology applying random positioning of dots for optimal results.

EVGA (Extended Video Graphics Array)

Video display with a resolution of 1024 x 768 pixels.

Extended gamut printing

A printing process where manufacturers add additional ink colors to extend the standard CMYK range. The most used are light cyan, light magenta, orange, green and various shades of black.

Exposure

Quantity of light per unit area (illuminance of the image plane multiplied by exposure time) reaching a photographic film or an electronic image sensor.

Extended gamut printing

A printing process where manufacturers add additional ink colors to extend the standard CMYK range. The most used are light cyan, light magenta, orange, green and various shades of black.

Extended Graphics Array (XGA)

Display standard published by IBM featuring a spatial resolution of 1024 x 768 pixels and 256 colors.

F

False colors

Sets of color rendering methods used to display colors belonging to visible or non-visible parts of the electromagnetic spectrum.

Feather

A technique available in many image editing programs that softens the outlines of a selected region or blurs an area over a specified number of pixels.

File compression

Reducing the size of a file to facilitate its transmission. The two basic types of compression are lossy compression and lossless compression.

File format

A particular organization of digital information from a program and intended for a specific use, such as the Graphics Interchange Format (GIF) or the Tagged Image File Format (TIFF).

Filters

In an image editing application, a function that uses algorithms to modify digital images by changing values or rearranging specific image areas. Term also relating to an optical device which selectively attenuates the light intensity passing through it depending on the properties of the light source. Common filters attenuate light depending on wavelength or polarization state.

Firewall

Security system that prevents unauthorized access to resources or information on a network and thus prevents their transfer to another network.

Stray light

Light not forming an image which may cause image degradation.

Flash

Adobe® application used to transmit vector graphics and sound over the Internet.

Flatbed scanner

A type of scanner that captures image data using a linear array detector.

Flexographic printing

Rotary letterpress process using flexible plates and fast-drying inks

Fluorescence

The process by which energy, usually UV rays, is absorbed by certain chemicals or materials and then re-emitted at other, often higher wavelengths.

Fluorescence lamp

Low pressure mercury vapor electric discharge lamp incorporating a fluorescent coating (phosphor) which transforms the ultraviolet radiation generated by the discharge into visible light.

Fluorescent whitening agent

Fluorescent dye or pigment that absorbs UV radiation and re-emits energy at a higher wavelength in the form of visible light (blue-violet), inducing a white appearance.

FMC-2

Color difference equation developed by Friele, MacAdam and Chickering. The equation was based on the results of a thorough visual assessment. For most colors, a Total Difference (Delta E) value of 1.0 represents barely noticeable variation.

FOGRA

FOGRA (Graphic Technology Research Association), headquartered in Munich, Germany, is dedicated to research and development in the field of printing technologies. FOGRA's tasks are research, development, transfer of know-how to industry, development of standards, consultancy and preparation of technical reports.

Foot candle

Quantity of light that strikes at a point on a flat surface of about 30 cm (one foot), perpendicular to the international candle.

Police

Typographic typeface style consisting of a set of numbers, letters and symbols.

Format

Printer surface of a printing system or width of a graphic / support. The "medium size" is typically 11-24 inches (approximately 28-61 cm) wide, the "large size" is greater than 24 inches (61 cm) wide, while the "extra large" is often larger. at 72 inches (approx. 183 cm) wide.

Quadrichromy

Printing process using cyan, magenta, yellow and black inks to render a wide range of colors. Another term used: "CMYK printing" or "four-color printing".

FPO (For Position Only)

Term for a low resolution image used in layouts to define the correct location for the high resolution image.

Fractal

Mathematically generated shape with an infinite amount of image detail.

Fractal compression

Compression scheme based on converting image files into mathematical equations. This method makes it possible to produce very high compression ratios.

Frequency modulation screening

A halftone screening method where all the halftone microdots are the same (small) size, but have variations in the average number per area or in the frequency depending on the tonal value to be reproduced.

Lost paper

A term used in printing to refer to an image or an inked area that extends beyond the edge of the printed page on all four sides.

G

Gamma

A measure of the amount of contrast in an image based on the slope of a gradient curve. A high contrast (steep curve) shows a high gamma value, while a low contrast (little curve) indicates a low gamma value.

Gamma correction

Nonlinear tonal correction of the gamma curve of an image. This method is typically used to manipulate shadows in an image to brighten the image without blurring out highlights.

Gamut

Color range available in an image or reproducible by output equipment. A color is said to be “out of gamut” when its position in the chromatic space of one device cannot be directly converted into the color space of another device.

Gamut compression

Retouch an image to reduce its gamut so that the image can be displayed or reproduced within the limits of a given device.

Gamut Mapping

A term that could be translated as “gamut matching” and which designates the conversion of the gamut of an image into the CIE chromatic space.

Gas Ghosting

A phenomenon characterized by the formation of a ghost or cloudy image on printed output due to improper drying of inks. It occurs most often with "barrier" paper, such as laminated backing papers, and can be avoided by careful or accelerated drying of the print.

Gaussian blur

Smoothing effect of an image obtained by applying a bell-shaped Gaussian distribution to soften the image.

Generation loss

Loss of quality or data of an image that occurs when the image is reproduced multiple times.

Geometric attributes

Characteristics associated with the distribution of light emanating from an object, including brightness, haze, texture, shape, viewing angle, and periphery.

Geometric metamerism

Property that affects two samples (usually with a largely textured surface), which appear to be identical at a given lighting or viewing angle, but no longer match when that angle is changed.

Ghosting

In image editing software, the effect of changing the degree of opacity of an object.

Graphics Interchange Format (GIF)

A data compression format mainly used to display images on the Internet.

Global chromatic correction

Correction that affects all the colors of an image.

Shine

An additional parameter to consider when determining a color standard, along with the hue, value, chroma, texture and metallic or pearlescent properties of a material. Gloss is an additional tolerance parameter that can be specified in the Munsell tolerance map. The general rule of thumb for evaluating the brightness of a color sample is as follows: the higher the brightness value, the darker the color sample will appear. Conversely, the lower the gloss, the brighter the sample will appear.

Gloss differential

A problem with some ink / paper combinations that is characterized by brownish reflections in inked areas that juxtapose with areas associated with little or no ink, resulting in total paper reflection. Another term used: "bronzing".

Glossmeter

Instrument used to measure the proportion of gloss (term used to describe the relative amount of specular reflection generated by the surface of a sample). These instruments measure reflected light at selected specular angles (20 degrees from perpendicular, 45, 60, 75 and 85 degrees, for example). The results obtained vary greatly depending on the design of the instrument, the calibration technique used, the type of sample, etc.

Goniochromatic Adjective describing a colored material exhibiting a property of goniochromism.

Goniochromism

Phenomenon where the color of a material changes depending on the angle of illumination or observation.

Goniospectrophotometer

Instrument used to measure a spectrophotometric curve at various angles of incidence and reflectance. Depending on the model, the angles of incidence and reflectance can be modified or fixed (15, 45, 75, 110 degrees, for example).

Degraded

Harmonious transition between two colors.

Graphics file format

File format used to store file formats used to save digital images, such as GIF, BMP, JPG, and TIF formats.

Graphics Interchange Format (GIF)

A type of image format generated specifically for computer use. As its resolution is generally very low (72 dpi or equivalent to that of your computer screen), this format is not suitable for printing. The GIF format is supported by a variety of applications and applies LZW lossless compression.

Graphic tablet

Instrument providing precise control of cursor movements in drawing or graphics programs, through the use of a stylus or pencil.

Heliogravure

Intaglio printing process using engraved cylinders which retain ink in hollow areas. This type of printing is ideal for long runs, such as magazines and packaging, and accepts most media.

Gray Component Replacement (GCR)

The process of removing the areas where cyan, magenta, and yellow inks overlap, replacing them with black ink in the black separation.

Shades of grey

Achromatic scale going from black to white with a succession of increasingly clear gray shades. This succession can consist of graduations located at an equal distance from each other (Munsell value scale, for example) or can be organized according to other criteria such as geometric progression based on luminosity. These scales can be used to describe the relative difference between two similar colors.

Scrub

In offset lithography, an operation which aims to spread a thin dried film of gum on the surface of non-printing regions to prevent its oxidation by oxygen in the air.

H

h

Coordinate of the tint angle in the CIE L * C * h color space. The angle refers to the location of the hue value on the CIE L * C * h color wheel, where red is 0, yellow is 90, green is 180, and blue is 270.

Halftone

Method of representing the tones of an image by points of different sizes.

Halftone cell

A matrix of printing dots that can be combined to produce various sizes of halftone dots.

Paper proof

A printed proof of a document showing the rendering of colors when reproduced on a specific output device, typically a commercial printing press.

Haze

Scattering of light by an element responsible for the apparent reduction in the contrast of objects viewed through it or by reflection on the surface.

Heatset ink

In offset printing, a fatty ink specifically formulated in which the binder or the vehicle comprises solvents. Its drying is accelerated due to a higher temperature.

High fidelity color

Extending the tonal range of color images by using stochastic printing and using six or more color inks to print the images, instead of the traditional four colors used in CMYK printing.

High light

Region of a shiny object exhibiting specular reflection. This is normally the color of the light source, not the object.

Histogram

Graphical representation of the tonal values (brightness or color) of a scene, according to the frequency of occurrence of each value.

HSB (Hue-Saturation-Brightness)

Equipment independent three-coordinate color model in which numerical values describe hue, saturation and brightness.

HSL (Hue-Saturation-Lightness)

Color space used to represent images based on polar coordinates. Light intensity is the vertical axis of the polar system, hue is the relative angle, and saturation is the planar distance from the axis. HSL space is considered more intuitive to manipulate than RGB space.

HSV (Hue-Saturation-Value)

Chromatic space describing color by means of three basic components: hue, saturation and gloss.

HTML (Hyper Text Markup Language)

A computer language that uses a standard set of tags to tell the web browser how to display text and graphics.

HTTP (Hyper Text Transfer Protocol)

Standard allowing web users to transfer information in web pages.

Concentrator

A device that connects two or more devices so that they can communicate.

Tint

Color attribute used in the Munsell color ordering system that distinguishes red from green, blue from yellow, etc.

Hunter Lab

Uniform color space (the opposite of the color gamut) in which the colors lie in a three-dimensional system of rectangular coordinates. The three dimensions are brightness (L), red / green tint (a), and yellow / blue tint (b).

I

ICC (International Color Consortium)

A group of companies united by an agreement that develop standards defining the chromatic and reproduction characteristics of media and hardware / software components, independently of the characteristics specific to each device.

ICC Profiles

A set of data that characterizes a color input device, output device, or color space, according to ICC standards. Profiles describe the color attributes by matching the target or source color space of the device and defining a profile connection space, CIELAB (L * a * b *) or CIEXYZ. Each device that captures or displays color can have its own profile. The ICC standard provides profiles in RGB format for scanners, digital cameras and displays, in CMYK format for printers and proofing systems, and in multicolor format for multicolor printing processes.

Illumination

Amount of light striking a unit area, measured in lux.

Illuminating

Mathematical representation of a theoretical real light source, used to derive trichromatic values from a spectrophotometric measurement. The figures represent the relative power of the theoretical source at any point of the visible spectrum. It is possible to use the relative power distribution of a real source for the calculation, but real sources are difficult to standardize.

Illuminant A

Mathematical representation of tungsten-halogen (incandescent) lighting. Color temperature: 2856 K. It is used in particular for metamerism tests. Simulates typical household or store lighting.

Illuminant C

Mathematical representation of filtered tungsten-halogen lighting (daylight). Color temperature: 6,770 K. It is used in particular for metamerism tests. Simulates average CIE natural light.

Illuminant CWF-2 (F2)

Mathematical representation of commercial broadband lighting used in the United States (cold white fluorescent). Color temperature: 4,150 K. It is used in particular for metamerism tests. Simulates typical US office or store lighting.

Illuminant D50

Mathematical representation of daylight at noon. Color temperature: 5,000 K. Used for general color evaluation, metamerism testing, and evaluation of color uniformity and quality in the graphic arts industry.

Illuminant D55

Mathematical representation of daylight at noon. Color temperature: 5500 K. It is used in particular for metamerism tests. Simulates average CIE natural light in daylight at noon.

Illuminant D65

Mathematical representation of the average daylight in the North. Color temperature: 6500 K. Used for general color evaluation, metamerism testing, providing visual correlation with measurements from spectrophotometric instruments, and compliance with European and European standards. Simulates the average natural light in the northern sky.

Illuminant D75

Mathematical representation of daylight in the North. Color temperature: 7,500 K. Used for general color evaluation, metamerism testing and visual evaluation of opaque materials as specified in ASTM D1729. Simulates natural light in the northern sky.

Illuminant DLF-7

Mathematical representation of a broadband fluorescent commercial lighting used in the United States (Deluxe). Color temperature: 6500 K. It is used in particular for metamerism tests.

Illuminant NBF-7

Mathematical representation of narrowband fluorescent commercial lighting used in the United States. Color temperature: 4000 K. It is used in particular for metamerism tests. American equivalent of the illuminant TL84.

Illuminant SPL (D65)

Mathematical representation of GretagMacbeth's patented filtered tungsten-halogen lighting, such as that of the SpectraLight (Daylight). Color temperature: 6500 K. Used for accurate color evaluation, metamerism testing, providing visual correlation with measurements from spectrophotometric instruments, compliance with European and European standards and compatibility with current automotive standards. Simulates the average natural light in the northern sky.

Illuminant SPL (D75)

Mathematical representation of GretagMacbeth's patented filtered tungsten-halogen lighting, such as that of the SpectraLight (Daylight). Color temperature: 7,500 K. Used for accurate color evaluation, metamerism testing and visual evaluation of opaque materials as specified in ASTM D1729. Simulates natural light in the northern sky.

Illuminant SPL (HOR)

Mathematical representation of tungsten-halogen lighting such as that of the SpectraLight (Horizon). Color temperature: 2300 K. It is used in particular for metamerism tests. Simulates the light of dawn or dusk.

Illuminating TL83

Mathematical representation of a commercial rare earth phosphorus, narrowband fluorescent lighting used in Europe and the Pacific region. Color temperature: 3000 K. It is used in particular for metamerism tests. Simulates typical office or store lighting in Europe and the Pacific.

Illuminating TL84

Mathematical representation of a commercial rare earth phosphorus, narrowband fluorescent lighting used in Europe and the Pacific region. Color temperature: 4,100 K. It is used in particular for metamerism tests. Simulates typical office or store lighting in Europe and the Pacific.

Illuminating TL85

Mathematical representation of a commercial rare earth phosphorus, narrowband fluorescent lighting used in Europe and the Pacific region. Color temperature: 5,000 K. It is used in particular for metamerism tests. Simulates typical office or store lighting in Europe and the Pacific.

Illuminating U30

Mathematical representation of a commercial rare earth phosphor, narrowband fluorescent lighting. Color temperature: 3000 K. It is used in particular for metamerism tests. Simulates typical lighting for Sears stores. American equivalent of the illuminant TL83.

Image enhancement

Processing of an image to improve certain elements, correcting color, tonal range and defects.

Direct film exposure system

A high resolution printer (typically 1270 to 4000 dpi) used in the printing industry to expose a bitmap image to photosensitive media.

Import

The ability of a software application to accept files saved in a different native file format.

Taxation

The process of placing the pages of a publication in the correct position to ensure the correct page order after printing and binding are complete.

Incandescent

Lamp in which light is produced by a filament heated by an electric current that makes it glow.

Index color

A subset of colors belonging to a specific color system and defining the palette used in an image.

Ink

A fluid or viscous substance used for writing or printing. In digital inkjet printing, a substance (liquid or solid) spread over the support, consisting of a dye, a solvent or a vehicle, and various additives.

Adjuvant

Resins used as additives in inks used in commercial printing to modify tackiness, film strength and ink gloss.

Inkwell

Reservoir or tray attached to the offset press that contains the printing ink.

Inking limitation

Control of a program that limits the percentage of ink applied to a print area.

Inkjet printer

Non-impact printing system that projects tiny drops of ink onto a surface.

Ink net

Ink line left on the plate indicating the pressure of the rollers.

Inking

Distribution of ink on the form by the ink rollers.

Input device

Hardware equipment capable of sending information to a computer, such as a digital camera or scanner.

Input profile

A profile that describes the color attributes of a particular input device, such as a digital camera or scanner, and which enables colors to be accurately converted into the color space of a given output device.

Integrating sphere

Sphere made of or coated with a highly reflective material that transmits light to it.

Interlaced display

A technique for displaying images at a resolution higher than that of the screen. The screen displays the two images alternately at the rate of every other row of pixels, at each refresh (ie at a frequency of one fiftieth of a second), creating a flicker artefact.

Internet

A set of interconnected networks forming a worldwide TCP / IP network.

Internet Service Provider (ISP)

Organization that sells Internet access services.

Interpolated resolution

The process of increasing the size of an image by using neighboring pixels to estimate the color of the pixels in the new enlarged image. Establishing the average color values of the surrounding pixels makes it possible to create new image pixels without generating irregularities (or escalation).

Intranet

Internal network based on the TCP / IP protocol that allows the sharing of resources, such as printers, files and storage space, on a single server.

Inversion

Technique of inverting light / dark values and / or colors in an image.

IP (Internet Protocol)

Address (Internet Protocol) of a computer on a TCP / IP network, which consists of four groups of up to three digits separated by periods. For example: 121.119.115.11.

ISO

Representation of the light sensitivity of an image sensor. The higher this value, the greater the light sensitivity. However, increasing the ISO value can also result in increased noise.

IT8

Standard test charts used for the color characterization of various devices and media such as scanners and printers, established by the IT8 committee of the American National Standards Institute (ANSI).

J

Staircase effect

An effect caused by images or lines rendered at too low a resolution which produces a stepped gradient effect giving the image a non-smooth appearance. Another term: "aliasing".

JPEG (Joint Photographic Experts Group)

24-bit bitmap color file format that allows the user to specify the amount of lossy compression applied to the file. This format is supported by most imaging applications and is best suited for continuous tone images.

JPEG 2000 (JPEG 2000: image coding system)

Officially called “ISO 15444”, a standardized format which extends the capacity of management and transfer of continuous tone images without noticeable loss of quality.

K

K / S (K over S)

Ratio between the absorption coefficient (K) and the scattering coefficient (S) in the context of a reflectance measurement. This value is derived mathematically from the reflectance measurement by expressing the reflectance (R) value as a decimal number (for example, 60 %R is equivalent to 0.6R).

Kelvin (K)

Unit expressing the color temperature, used in imaging to define the quality of a light source in relation to the absolute temperature of a black body diffusing an equivalent energy. Typically, a tungsten bedside lamp is equivalent to 2,800 degrees Kelvin; TV or quartz lights are 3200 degrees Kelvin, and outdoor lighting averages around 5600 degrees Kelvin. The higher the temperature in Kelvin, the more bluish the light.

Core size

The number of pixels sampled as part of the image manipulation and sharpening processes.

Key

Term designating black ink in the English name of the CMYK printing process (CMJN in French).

Thick headed

Self-service station installed in a public space and allowing customers to access various imaging and egress capabilities.

Kubelka-Munk

Phenomenological theory in a turbid medium relating the reflectance and the transmittance of diffusion and absorption of matter with respect to optical constants. The theory includes variables where K is the absorption coefficient and S is the diffusion coefficient for dye concentrations. Also referred to as K / S (K over S), this relationship forms the basis of almost all computerized color matching calculations.

L

L * a * b * (CIELAB)

Chromatic model best describing human vision. This model is based on three variables: L * (brightness), a * (first color axis) and b * (second color axis).

Lambert's law

The reflected flux per unit of solid angle is proportional to the cosine of the angle measured from the axis perpendicular (normal) to the surface.

LAN (Local Area Network)

A group of computers whose operation is limited to a certain distance (office or building, for example).

Lacquer

Water-based transparent resins or solvents, applied to a printed sheet to protect it or give it a shiny, mat or satin finish.

Large format

Printer, media or printed output with a minimum width of 24 inches (approximately 61 cm).

Laser

Intensely focused light beam with a very narrow spectral distribution. Lasers are used to write data to certain storage media, such as CDs, or in certain types of digital printers.

Laser printer

A printer that uses a laser beam to write on a rotating photoconductive drum coated with toner. Once transferred to the paper, the image passes through two heated rollers or an oven that mix the toner to fuse it with the fibers of the paper.

Lasso

Tool found in many image editing applications that allows the user to select an area of an image by drawing a line around it.

Late-bound workflow

Postponing the color conversion process in the space of the final output until the very end of the workflow.

Lux

A measure of the intensity of light that hits or passes through a surface, as perceived by the human eye.

Layer

Level of an image that can be edited independently from the rest of the image.

Layering organization

In image editing software, positioning an image or graphic on another element so that the opacity of the upper image allows viewing of the lower image.

LCD (Liquid Crystal Display)

Computer display technology that is based on the changing optical density of certain types of molecules when placed in an electric field. The LCD display can be active matrix or passive matrix.

LED (Light Emitting Diode)

Semiconductor that emits light when an electric charge passes through it. LEDs are used in display devices, as well as some types of digital photo printers.

Lenticular

A combination of interwoven digital images which, when viewed through a specifically designed plastic lens, create an illusion of depth or movement.

Light

Electromagnetic radiation with a wavelength between 380 (purple) and approximately 770 (red) nanometers (nm), and which can be perceived without assistance by the normal human eye.

Light source

Part of an instrument or visual observation situation that provides radiant energy in the form of light. The emission can also be described by its correlated color temperature.

Light stable

Said of an object that can resist the destructive action of light.

Brightness

One of the three dimensions describing color. Attribute by which observers distinguish white objects from gray objects, and light-colored objects from dark-colored objects.

Line art

Monochrome diagrams or drawings. Image requiring sharp edges and high contrast between inked areas of the image and non-inked areas. Drawing only in black and white, without intermediate grayscale. These images require high resolution to generate the necessary sharpness.

Linear network

Image sensor including red, green and blue sites arranged in a linear fashion.

Linearization

A process of measuring and correcting a device's inability to see or reproduce a straight line made up of tones ranging from black to white. Linearization is an essential preliminary step in the configuration of a color system.

Linear frame

A term used in printing to define the density of elements in a halftone cell, expressed as the number of lines of ink dots per inch or per millimeter.

Lithography

Printing process using a stone or metal plate on which the image to be printed is "in love" with ink, and the blank area refractory to ink.

Local chromatic correction

Correction that affects only the colors of a selected area of an image.

Log absorbance

Logarithm to base 10 of the absorbance values for each wavelength. A spectral plot (log absorbance versus wavelength) indicates that the vertical distances between two curves (samples) are almost identical for all wavelengths. This means that the vertical position of the curve is directly related to the dye concentration or the thickness of the sample. Furthermore, the shape of the curve is independent of the dye concentration or the thickness of the sample.

Log K / S

Logarithm to base 10 of the K / S values for each wavelength. A spectral plot (log K / S versus wavelength) indicates that the vertical distances between two curves (samples) are almost identical for most wavelengths. This means that the vertical position of the curve is directly related to the dye concentration. Furthermore, the shape of the curve is mainly independent of the dye concentration.

LUT (Look-Up Table, conversion table)

A table of color values that is used to convert colors from one color space to another to support digital input and output data from different output devices.

Lossless compression

Compression technique allowing to reduce the size of a file without losing any original data. This compression involves various encoding schemes which ensure the re-creation of the original data from the compressed format.

Lossy compression

Compression technique for reducing the size of a file by removing some data from the original image. The proportion of initial data to be kept is arbitrarily defined by the user according to the quality required for the intended use.

lpi (lines per inch, lines per inch)

Number of lines per inch in a halftone screen. As a general rule, the higher the lpi value, the better the resolution and quality of the printed output.

Lumen

A measure of the frequency at which a source emits light. ANSI lumen is used to define the brightness of overhead projectors and video projectors.

Luminance

Frequency at which a source emits light in a specific direction. Also matches the brightness of a composite video signal.

Brightness

Distribution of light and dark values in an image.

Chandelier

The characteristic appearance of a surface that reflects more in some directions than in others, but not so much that it forms transparent flipped images.

Lux

A measure of the intensity of light that hits or passes through a surface, as perceived by the human eye.

M

MacAdam Ellipses

Ellipsoids plotted on the chromaticity diagram and which correspond to a barely perceptible variation from the color represented by the center of the ellipsoid. The size and shape of ellipsoids depend on their location on the chromaticity diagram.

MacAdam Unit

Unit expressing the difference in color calculated by the equation FMC-2. A MacAdam unit (1: 0) corresponds to a barely noticeable variation, based on experimental results.

Marquise

In image editing programs, a tool used to select an area generally by surrounding it with animated dotted lines.

Mask

Special effect for modifying images to make only part of the image visible or to blend the image into the background.

Match

Usually, two colors match if their appearance is the same (have the same color coordinates). This term is often used to refer to a spectral match, meaning that the two colors appear the same (same color coordinates), regardless of the illuminant or the observer.

Matrix

Plate or surface on which an image is inscribed and which serves to retain ink before the image is transferred to media or paper. In digital printing, the matrix is the electronic file stored on a computer's hard drive or on a disc or CD. This matrix consists of binary encoded information that describes the final appearance of the image file on the printed output or rasterized digital image.

Matte rendering

Surface that does not show any shiny appearance at any viewing angle. High diffusion reflective surface.

Support

Material that can be printed on, such as paper, canvas, cotton, or plastic. A term very frequently used in digital printing.

Metafile

A file format that contains both bitmap and vector data, and is used on different equipment and in various applications.

Metameric pair

Pair of colors that appear the same when viewed under certain viewing conditions, and different if viewing conditions change.

Metamerism

Phenomenon characterized by a pair of colors that match in a set of given conditions, real or calculated, but no longer match when those conditions change.

Metamerism index

Special formula used to calculate the difference between two colors exposed to two different light sources. A metamerism index greater than 2.0 usually indicates that metamerism is visible to the naked eye.

Mezzotint

A tonal engraving process where the surface of the plate is roughened by a mesh of small, deburred holes. The artwork is then produced by polishing and browning the selected areas, which appear in relief.

Microporous

Inkjet media with a receptor coating with voids that fill with ink. The ink is quickly absorbed into the media instead of being applied to its surface. This rapid absorption makes the support instantly dry to the touch.

Medium tones

In an image, tints that are in the middle of the tonal range, halfway between the lightest and darkest colors. Another term used: "average values".

Missing profile (no match)

In Adobe® Photoshop®, displaying a profile mismatch message indicates that the software has identified an image with a different embedded profile than the current workspace.

Moiré

An unwanted pattern that sometimes appears when combining overlapping halftone screens. It is often sufficient to change the screen angle to eliminate this effect.

Screen calibration

The process of adjusting a video display relative to a known set of values so that it closely matches the input and output devices.

Screen Profile

Describes the coordinates of the RGB space, the gradient curves of each color channel, and the black point and white point.

Monochrome

Image consisting of a single color range.

Monotype

Printing process where each print in a series varies in color, design, texture, etc. compared to the underlying common image.

Mounting

Harmonious combination of divergent images in a single image.

Morphing

The effect of merging two images together by moving points from their original position to new positions to form a single image.

Marbling

Texture observed in smooth or uniform areas of an image, which can be caused by poor processing and the inappropriate use of various digital processes, such as excessive unsharp masking.

MPEG (Motion Picture Expert Group) compression

A collection of video and audio compression techniques that reduce image files at a ratio of up to 200: 1.

Multicolor print

Process color printing, plus a fifth, sixth, or even a seventh color to extend the color gamut and produce more accurate colors. PANTONE Hexachrome® is a six-color system that includes the colors orange and green.

Multimedia

Synthesis of different digital media combining texts, graphics, audio sequences, animations and videos in an interactive format.

Munsell system (color identification)

Chromatic model that identifies specific colors by their hue, value and chroma. The system consists of more than three million sample observations representing variations in hue, chroma, and value as seen by the human eye.

NOT

Nanometer (nm)

A unit of measurement equivalent to one millionth of a millimeter. Wavelengths are measured in nanometers.

Narrowband fluorescent

A generic term for fluorescent lamps (Ultralume and TL84, for example) which produce narrow bands of visible light relative to their phosphorescent mixture.

Noise

Random re-coloring of pixels creating a grainy pattern.

Non-impact printer

Printing technology where marks on paper are made without physical contact between the printer and the paper.

Not interlaced

Video system that displays all the horizontal lines of the screen in successive order. Computer screens are often non-interlaced, unlike television screens, which are usually interlaced.

Non-metameric correspondence

Pair of colors that remain the same, regardless of the observer and the lighting and viewing conditions. Unconditional correspondence.

Normal color vision

Vision of a normal observer showing no symptoms or abnormal or defective chromatic response.

O

Object

In the multimedia context, a piece of data stored in a video sequence, an audio file or a graphic representation; vector-based drawing.

Observer functions

The response of the average normal human eye at each wavelength has been measured by CIE through extensive experiments. Since there are three types of color sensors, three observer functions constitute what is commonly referred to as the standard observer.

Observer

Human observer who receives a stimulus and for which he feels a sensation. In the context of vision, the stimulus is visual, and sensation relates to appearance.

Observer metamerism

Pair of colors that match when seen by an observer, but no longer match with another observer.

Standard observer

Spectral response characteristics of the average observer, defined by the CIE. Two sets of data are currently defined: the 1931 data for the 2 ° field of view (remote viewing) and the 1964 data, which relates to the 10 ° ring field of view (viewing at a distance approximately corresponding to a length of arm).

ROC (Optical Character Recognition)

Technology used to convert scanned text on printed pages into editable ASCII text.

Offset printing (offset lithography)

A commercial printing method where ink is transferred from the printing plate to a rubber roller, before being printed on the paper.

OLE (Object Linking and Embedding)

Standard which defines a software communication channel allowing an object to be inserted into a document, without the latter losing the link to its original application.

Print on demand

Digital printing application where documents can be output to a printing device directly from a database, in varying quantities and on demand.

Opacity

Lack of transparency or translucency. A measure of the amount of light able to pass through a material. Density of a layer or color.

Opaque

Term used to describe complete opacity, that is, the degree to which a sample completely shields the media it is covering. Contrary to transparent.

Operating system

A system used by the computer to control basic input and output operations, and to operate software applications. Examples: Mac OS, Windows, UNIX and Linux.

Theory of opposing colors

Theory conceptually explaining how the human visual system (eye / brain association) perceives color. For the human visual system, red and green are opposite colors, just like yellow and blue. For a human observer, this means that a red object does not contain green (but it can also be blue or yellow), while a yellow object does not contain blue (but can also be red or green). Something that is neither red nor green is neutral from the point of view of the red / green criterion. Something that is neither yellow nor blue is neutral from the point of view of the yellow / blue criterion. If a color is neutral from the point of view of both criteria, it is "colorless" (such as black, gray or white). This theory forms the basis of most uniform color spaces (in particular CIELab, CIELCh and Lab).

Optical resolution

Maximum physical resolution of a device. Optical resolution provides better image quality than interpolated resolution, which uses software to create additional image information.

Orientation

Direction in which the page is printed. Horizontal direction = landscape; vertical direction = portrait.

Out of gamut

In commercial printing, a range of colors that cannot be reproduced in the CMYK color space.

Output device

Physical equipment capable of displaying information from a computer, such as a monitor or printer.

Output profile

A profile that describes the color attributes of a particular output device, such as a display, projector, or printer, and which allows colors to be accurately converted from the color space of a given input device.

P

Palette

Range of color or tint available in the imaging process. This term also refers to a mobile menu of tools or options accessible in software applications.

PANTONE®

Company known primarily for its Pantone Matching System (PMS), a proprietary color space used in multiple industrial sectors, such as printing, painting, and textile and plastic manufacturing. The Pantone Matching System is a uniform color reproduction system, which allows different manufacturers based at different sites to name and communicate over 3,000 distinct colors.

PANTONE System

One of the most well-known color specification systems used by designers and printers to communicate color. Available in coated, uncoated and matte versions, each color chart contains a series of colors that can be referenced based on their PANTONE rating.

PDF (Portable Document Format)

A type of document created by Adobe®, allowing information to be displayed regardless of the platform. Converting a file to PDF will allow all items, such as text, graphics or PostScript files, to be accurately reproduced on any computer system using free Adobe® Acrobat viewing software. ® Reader.

Intention of perceptual rendering

Perceptual rendering attempts to preserve the relationship between colors out of gamut by compressing the entire tonal range, even if doing so results in inaccuracies in colors within the gamut. This results in harmonious color gradients. Even though the perceptual rendering compresses the entire gamut, it defines the central tints more precisely than those located at the edge of the gamut. Perceptual and relative colorimetric renderings represent the types of conversion most used for digital photography.

Peripheral

External device that can be connected to a computer.

Phase change printer

Inkjet printer where the ink, initially solid, is then heated, liquefied, then sprayed on a support.

Phosphor

A material emitting light by the excitation of an electric charge, used in the manufacture of cathode ray tube display units.

Photochromism

Reversible change in the color of a sample under the effect of exposure to light.

Photoshop (.psd)

Adobe®Photoshop® software proprietary file format that supports all application functions, such as layers, masks, and channels. This file format is not supported by other applications.

Photopic vision

A term for vision mediated by conical receptors in the retina of the eye, which allow color vision at high and medium levels of luminance.

PICT (.pct)

Up to 32-bit bitmap color file format originally designed to support graphics applications running on the Apple® Macintosh® platform. This file format is supported by various applications and is frequently used to transfer files between applications. This file format e