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.

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 is compatible with JPEG lossy compression schemes.

Pigment

A type of dye made up of particles made up of many synthetic molecules or carbon black. Generally more stable than dyes of the same color. Pigmented inkjet inks have a longer durability and can be matched with a narrower color gamut.

Pixel

Individual points used to display an image on a computer screen. The number of pixels defines the size and resolution of the image.

Pixel depth

Amount of data used to describe each point of color on a computer screen. For example, a pixel depth of 1 means that only black and white will be displayed. If the depth is 4, 16 different colors can be displayed.

Planographic

In the context of engraving, an adjective referring to the area occupied by ink on its plane side, as opposed to the recessed or raised area retaining the ink.

Plate cylinder (printing)

Cylinder that carries the paper during printing on some presses and offset presses. This cylinder works somewhat differently from one printing process to another.

Platinum

Glass surface of a flatbed scanner on which the model reproduced by reflection is positioned for scanning.

Plug and play

The ability of an operating system to identify a device and adapt the configuration to integrate it.

Plug-in

Third-party software loaded in the Photoshop® plug-ins folder and accessible from a Photoshop menu.

Photomultiplier tube

A photosensitive device commonly found in drum scanners. These electron tubes are much more sensitive to light than CCD arrays.

PNG (Portable Network Graphics)

A 24-bit bitmap color file format that uses lossless compression, originally intended as an alternative to GIF for transferring and viewing images online.

Portrait (Fashion)

Orientation of an image that is larger (horizontal plane) than wide (vertical plane). This term also denotes a parameter intended to control an output peripheral so as to adapt a computer document to the print medium.

Finishing plaster

Transparent substance applied as a finish to protect prints or works.

Posterization

Transformation of an image into a more basic form by limiting the number of tonal values, thus creating a striking surreal result.

PostScript

Page description language created and licensed by Adobe®, used to display and print fonts and images.

ppi (pixel per inch, pixel per inch)

Unit used to measure the resolution of a bitmap image.

Preflight check

The process of checking a job for possible problems, such as missing fonts and images or incompatible color systems, before sending the job to the workflow.

Prepress

The process of preparing a job for printing, including defining the layout definition and the color separation.

Primary colors

Colors, usually three in number, which are combined to produce the entire color range of a given color model. Thus, non-primary colors are a mixture of at least two primary colors. Red, green and blue represent the primary colors of the additive model. Cyan, magenta, and yellow are the primary colors of the subtractive model.

Print density or optical density

Visually perceptible and measurable absorption of light on the surface of a support, due to the presence of a dye. Optical density only measures the surface density of a dry paper output, not the density of the total amount of ink applied to the media.

Print on demand

In digital printing, the ability to consistently produce prints individually or sporadically over an extended period of time, allowing orders to be accepted in small quantities.

Printing permanence

Resistance of a print to any physical change, such as light, heat, acids, etc.

Printing service provider

A commercial digital printing agency or company that prints an ordering party's image file according to the required specifications.

Printer driver

Printer-specific software that allows a computer to communicate with the printer. See also RIP.

Profile (printer)

Profile by which the color management system converts the colors of a given image into the color space of the printer, so that the colors are printed correctly.

Full color printing

Printing using all three primary inks (cyan, magenta and yellow) plus black.

Profile

Describes how a device "sees" color by characterizing an 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.

Profile (photograph)

In a photo workflow, a color profile describing how a device reproduces color. Custom profiles are created using color management software and relate to each device involved in the workflow (cameras, monitors, tablets, phones, projectors, and printers).

Profile (projector) Profile by which the color management system converts the colors of a given image into the projector color space, so that the colors appear correctly when projected onto a screen.

Profile (scanner) Profile describing the conversion of the RGB space specific to the scanner to the CIELab system. The test chart determines which colors from the original will be converted to specific scanner RGB colors. However, since a test chart only covers part of the scanner's color gamut, the characterization software's task is to provide a description of colors outside of the device's gamut.

Profile (tablet)

Profile by which the color management system converts the colors of a given image into the tablet's color space, so that the colors appear correctly when projected on a screen.

Profile (video)

In a video workflow, a color profile that describes the process of creating a specific look-up table (LUT) for video recording.

Profile editing

Programs that allow users to modify ICC profiles for better subjective color matching.

Test

Prototype showing the printer and the customer the expected result of the job once printed and allowing all necessary changes to be made before the job is sent to the press. Individual photo proofs are called “scatter proof” or “loose proof”. Imposition proofs are page proofs and proofs showing how several pages are organized on a large press sheet.

Proofing system

Device for showing what a printed job will look like before it is sent to the press.

Psychophysics

In the field of color science, a term that refers to the relationship between physical description and the resulting sensory perception.

Purity

Degree of saturation of a color.

Q

Quadtone inks

Special multi-monochrome (B&W) inks.

Quark

Layout software for design and publishing professionals.

Waiting line

A series of tasks or operations waiting to be performed by a computer or device.

QuickTime

Video and audio playback application developed by Apple® Computer.

Quick drying ink

Ink dries much faster than conventional inks. This type of ink contains a certain proportion of solvent which is quickly absorbed by the paper and thus accelerates drying.

R

Radiant energy

Energy emanating from the electromagnetic spectrum, propagating at a speed of 299,792 kilometers / second through a vacuum, and more slowly in a denser medium (air, water, glass, etc.). The nature of radiant energy is characterized by its wavelength or frequency, even if it behaves in parallel as a separate quantum (corpuscular theory). The various types of energy can transform into other forms of energy (electrical, chemical, mechanical, atomic, thermal, radiant), but the energy by itself cannot be destroyed.

Raster image

Image composed of lines of pixels in a grid layout or in bitmap mode.

Screening

Transformation of vector image information into raster image information.

RAW

File format that allows the user to specify the file type, file author, and header information, and which supports up to 48-bit color data without compression. Due to the amount of information and knowledge required to exploit this format, novice users rarely resort to it.

Laminated Backing Paper (RC)

A term for photographic paper coated with a layer of polyethylene on each side, used in most color printing applications and some black and white applications.

Receiver coating

A chemical layer applied to the surface of a media that receives and fixes ink from the printhead nozzle.

Coil

Large roll of paper used on printing presses.

Reference

In evaluating the color difference, the color against which all measurements are compared. Another term used: "standard".

Reflectance

A measure of light reflected from a surface, which varies with the wavelength of light.

Specular reflectance

Shimmering reflectance. The magnitude of specular reflectance on shiny materials depends on the angle and scattering of light from an irregular surface.

Total reflectance

Reflectance of the radiant flux reflected from a surface at all angles. This term therefore covers diffuse reflectance and specular reflectance.

Reflection

The process by which incident light leaves a surface or medium on the incident side.

Reflective scan

A process used to scan a subject that does not pass light, such as a sheet of paper.

Refresh rate

Number of times a display updates data in a second.

Spotting

Aligning the layers of a CMYK separation so that all layers print exactly on top of each other and produce an accurate print.

Registration marks

Marks positioned on the edges of each layer of a CMYK separation and which ensure correct registration or alignment.

Relative colorimetric rendering intent

Rendering intent that maintains a near-exact relationship between colors falling within the gamut, while colors outside the gamut are cropped to the closest reproducible hue. Color data lost due to relative rendering intent is irreversible. This type of rendering is mainly used for logos, solids and vector colors.

Relief process

In the context of engraving, a process using incised, etched or sandblasted printing plates on which ink is deposited. Debossed lines or areas do not hold ink. The ink is then transferred from the surface of the plate to the paper by manual friction or using a press.

Removable storage medium

Storage device that connects to a similar playback device and can be removed / inserted as needed.

Return

Process of generating a 2D image from data contained in a 3D scene.

Rendering

Applying a shading effect to a digital image to make it appear more realistic.

Rendering Intent

When the gamut of the source color space is larger than the destination, saturated colors may be cropped (misrepresented) or more markedly burnt. To remedy this problem, the color management module has several methods. The ICC specification has four different rendering intents: absolute colorimetric, relative colorimetric, perceptual, and saturation.

Resolution

Amount of detail in a color or spatial variation that can be identified in an image. Refers to the number made up of the smallest discernible dots or pixels.

Resampling

Changing the resolution of a bitmap image without changing the file size.

Retouching

Manual or digital process of removing imperfections or unwanted parts of an image.

RGB (Red, Green, Blue)

Chromatic model composed of the primary additive colors, which can be mixed to obtain other colors.

Rgb printer

Printer that uses red, green, and blue ink to reproduce images on media, typically controlled by a manufacturer-specific driver and configured to accept RGB data only.

RGB natural color

RGB color system with 24-bit-per-pixel color resolution, capable of producing over 16 million colors per pixel. This type of system is generally referred to as the natural color system or the pure color system.

RIFF (Raster Image File Format)

File format used to store grayscale images.

RIP (Raster Image Processor)

Considered the “brain” of the digital output device, RIP mathematically converts digital graphics files into information that a printer can use to create images. In addition to processing, most RIPs have been customized to meet specific printer requirements and user needs. RIPs can handle layout, color control, archiving, and other operations.

ROM (Read-Only Memory)

Type of memory where data can only be read and cannot be modified.

Rosettes

A pattern generated in a printed image when halftone screens are subjected to conventional screen angles.

S

Sampling

A major method of digitizing analog information involving the performance of periodic measurements of analog information.

Saturation

Attribute relating to the perception of color and which expresses the degree of variation in relation to a gray of the same brightness. Grays have no saturation value.

Saturation rendering intent

Rendering intent that attempts to preserve saturated colors and is mostly used to maintain the color purity of computer graphics when converting into a larger color space. If the original RGB device has pure colors (full saturation), then the saturation intent ensures that those colors remain saturated in the new color space, even if they need to become relatively more extreme to do so.

To scale

A technique for enlarging or reducing an image by increasing or decreasing the number of scanned pixels or the sampling rate related to the number of samples per inch required by the printer or other output device.

Digitize

The process of converting an optical image into digital data.

To scan

Equipment for capturing an optical image through digital data.

Dispersion

Diffusion or redirection of radiant energy under the effect of exposure to particles of different refractive index. The phenomenon of dispersion occurs as soon as a similar interface occurs, on the surface or inside a support containing particles.

Scotopic vision

Vision mediated only by the retinal rods, at very low light levels. This is night vision.

Weft

Process used to produce halftone dots.

Screenshot

Captures data currently displayed on a screen.

Silkscreen

Impact printing technology based on the use of a stencil.

Display resolution

Number of distinct pixels that can be displayed in each dimension of a screen or television.

Selection

Isolation of a portion of a digital image in order to perform additional tasks or to protect the selected area from manipulations applied to the remaining “unprotected” areas.

Separation

Dividing continuous tone images into discrete CMYK components for printing.

Separation color

The color of a document that requires printing on a separate plate.

Shady

Coloring of a surface according to its incident light. The color depends on the position, orientation and attributes of the surface and the light sources.

Shadow

Subtlety in the darker portion of an image.

Shadow point

Darkest printable shade, other than black, in an image. Any tonal values below this threshold will print in black, with no detail.

Sharpness enhancement

Image enhancement technique where the contrast between specific pixels is increased.

Sheet press

Printing press fed by sheet media, not roll media.

Transparency

Phenomenon that occurs when the ink penetrates the paper support until it is visible on the back.

Side stop

System placed on the left or right side of the press to immobilize the sheet and keep it in position during printing.

Clipping

Hide or block an image to isolate it from the background.

Simultaneous contrast

Phenomenon that occurs when the way a color is perceived is influenced by the surrounding color.

Single lens reflex

Small format camera (35mm or 6cm) with a reflective mirror that retracts when the shutter is released. This type of device allows the photographer to view the image with the exact framing of the photo.

Screen test

Display of a digital image on screen, as opposed to the paper proof. It is very important that the display used for soft proofing is properly calibrated so that colors can be reproduced accurately.

Solid ink

Solid resin ink used in solid ink technology. The printhead and supplied ink are heated, melting the ink and bringing it to a very low viscosity. The ink is sprayed in the hot state, then cools on the surface of the support or on a drum, before being then transferred to the paper, in a manner similar to an offset press. Solid ink can be printed and transferred, or directly printed. Another term used: "phase change".

Spatial resolution

The smallest characteristic of an image that can be detected, expressed as a fraction of the total image.

Specifications for Web Offset Publications (SWOP)

American standards governing printing specifications on offset presses.

Spectral

Belonging to the visible spectrum. A term therefore relating to color.

Spectral data

Method for unique identification of an object based on the analysis of each of the wavelengths reflected by the object in question

Spectral power distribution

Graphical or digital representation of radiant energy per unit wavelength interval, for a given light source.

Spectral reflectance curve

Graphic representation of the chromatic composition of an object. The x-axis represents wavelengths, from 380 nm to 730 nm, while the y-axis corresponds to relative reflectance (amount of light reflected by the object expressed in %).

Spectrophotometer

Instrument which measures reflectance to light across the visible spectrum, in the wavelength range from approximately 380 to 720 nm. The very precise data obtained can then be converted into densitometric or colorimetric data. The spectrophotometer is the most frequently used measuring instrument because it can be used for both density calibration and ICC characterization.

Spectrophotometric curve

Curve measured on a spectrophotometer. The generated graph shows the relative reflectance or transmittance (or absorption) on the y-axis, and the wavelength or frequency on the x-axis.

Spectrum

Spatial organization of the components of radiant energy according to their wavelength, the number of waves or the frequency. In this context, it is the full range of visible wavelengths of light radiation.

Specular

Adjective designating the highlighting of an object by its shiny surface.

Specular reflection excluded (SCE)

Reflectance measurement excluding specular reflectance to include only diffuse reflectance.

Specular reflection included (SCI)

A measure of the total reflectance generated by a surface, including both diffuse reflectance and specular reflectance.

Specular gloss

Relative reflectance generated by a surface in the direction of the mirror or specular, expressed as a fraction of light.

Very high light

A small, high-light area of an image with little or no detail.

Specular reflection

Reflectance of a beam of radiant energy at an angle equal to but opposite to the angle of incidence. Shimmering reflectance.

Specular reflection excluded (SCE)

Reflectance measurement excluding specular reflectance to include only diffuse reflectance. Exclusion can be achieved by applying an incidence angle of 0 (perpendicular) to the samples. The specular component of the reflectance is then reflected back to the instrument by means of black absorbers or light traps at the specular angle when the angle of incidence is not perpendicular, or in directional measurements when taking a measurement at an angle different from the specular angle.

Specular reflection included (SCI)

A measure of the total reflectance generated by a surface, including both diffuse reflectance and specular reflectance.

Direct tones

Spot colors, such as PANTONE® tones, are ink colors selected from a specification guide and generally cannot be reproduced using CMYK colors. Each color is mixed and inserted on the press in a printing group. Spot inks are economical for two or three color printing, and can also be used for colors that are difficult to reproduce well with process printing. You can use spot inks for applications limited to three colors, other than reproducing four-color photos, or for printing logos or other graphic elements that do not require precise color matching.

sRGB

Color model that is part of standard RGB spaces. Primarily suitable for Internet images.

Standardized illuminant

Relative energy emitted by a real or imaginary light source, and which is mathematically defined for each wavelength of its distribution spectrum.

Standard

In evaluating the color difference, the color against which all measurements are compared. Another term used: "reference".

Standard observer (1931, 2 degree observer)

Standard observer (2 degree field of view) recommended by the International Commission on Illumination (CIE) in 1931. This observer is based on the results of a color matching experiment involving a 2 degree field of view.

Stochastic screening

A dithering process where dots of uniform size are placed at random to create an illusion of tint levels. Another term used: “FM screening” (frequency modulation screening).

Stop surface

Position on the feed table where the sheets are immobilized before being fixed to the clamps of the cylinders, in order to ensure that the lateral registration is maintained.

Stylus

Tool used on a graphics tablet as a drawing instrument or as a mouse.

Sub-sampling

Scanning at a sample rate lower than the optimal rate.

Support

Material that receives a printed image or dye.

Subtractive (reflective) color

In subtractive color systems, such as printing, the operation of removing a selection of colors that reflect or pass light. Subtractive primary colors are the opposite of additive primary colors on the color wheel: cyan (without red), magenta (without green) and yellow (without blue). Subtractive secondary colors include red (magenta plus yellow), green (cyan plus yellow), and blue (cyan plus magenta). The subtractive tertiary color is black (cyan plus magenta plus yellow).

Subtractive synthesis

Mixture of dyes taking into account both the absorption and the dispersion of at least two individual pigments making up the mixture.

Subtractive primary colors

Cyan, magenta and yellow. Theoretically, the combination at 100 % of the three subtractive primary colors on white paper produces black. Their association with different intensities generates a gamut composed of various colors. The combination of two primary colors at 100 % produces an additive primary color, namely red, green or blue.

Additional Observer (1964, 10 degree observer)

Supplementary observer (10 degree field of view) adopted by the International Commission on Illumination (CIE) in 1964. This observer is based on the results of a color matching experiment involving a 10 degree field of view.

Peripheral field

The portion of the field of view immediately surrounding the central field or model of interest.

SWOP (Standard Web Offset Printing)

Standards defining the color and speed characteristics of a press.

T

Reference

Whether visually or using color management software, reference images provide a range of color and grayscale for calibrating displays, printers, scanners and digital cameras.

Test charter

Collection of color patches used to generate ICC profiles of input and output devices. Test charts are provided on paper or transparent media, and are also available as electronic files.

Thermal inkjet printer

Printer using inkjet print heads equipped with a heating circuit (thermal) to produce the ink drops.

Thermal transfer printer

Digital printing equipment that transfers inks (resin or wax based) from a sheet or ribbon to a medium, such as paper or vinyl.

Thermochromism

Reversible change in the color of a sample, due to a change in the temperature of the sample in question. This phenomenon usually affects high saturation (vivid) colors, such as yellows, oranges, and light reds.

Third party software

Software distributed free of charge or sold by an entity other than the original provider of the development platform.

Thumbnail

Small format version of a larger graphic image, used for indexing image databases or for previewing a very large image.

TIFF or TIF (Tagged Image File Format)

Standard file format used in most digital imaging programs. Highly scalable, the TIFF format allows additional information to be added to image data through a repository of image files containing header type information but not actually part of the header. header of the file. TIFF can be used for black & white, grayscale, RGB, and CMYK images. This format can be decompressed and is compatible with many compression methods. However, it mostly applies LZW compression. It is probably the most versatile file format.

Mosaic

The process of dividing an image into sections for the purpose of retouching or printing.

Virgin shade

Mixture of a white pigment and absorbent (usually color) dyes. Result produced by mixing a white pigment and absorbent (usually color) dyes. The resulting mixture is lighter and less saturated than the color without the addition of white.

Topcoat

A coating applied to the surface of an inkjet or other medium during the manufacturing process. The topcoat improves ink adhesion and other performance characteristics, and helps regulate fattening, drying time and moisture resistance.

Tone curve

Curve describing the relationship between input values and output values relating to brightness or color, and which can be used to adjust the contrast of the image.

Toner

Dry powder pigment used in printers and fax machines, containing a dye, an electrostatic thermoplastic, a charge control agent, and generally a magnetic material.

Total color difference (∆ or Delta E)

Single number that defines the magnitude (size, degree, quantity) of the difference between two colors. This value does not indicate the nature of the color difference.

Total ink coverage

In CMYK printing, it is often important to limit the amount of ink applied to the page to avoid excessively long drying times, the risk of smudging and excessive ink consumption. In UCR (Sub-Color Removal) or GCR (Gray Replacement) separations, the total amount of ink to be affixed to a particular surface can be quantified as a total ink coverage defined on a scale of 0 to 400 %. The application of 100 % of C, J, M and N equals 400 coverage %. In UCR and GCR separations, total ink coverage in CMYK printing is typically limited to 200-320 %.

Total reflectance

Reflectance of the radiant flux reflected from a surface at all angles. This term therefore covers diffuse reflectance and specular reflectance.

Transmissive digitization

A scanner that allows light to pass through a transparent or translucent object, such as a negative or a slide.

Transformation

Mathematical conversion from one color space to another, for example from RGB to CMYK space.

Translucent

Diffuse transmission of light. No sharp image can be observed.

Translucency

Aspect that lies between full opacity and full transparency. Partially opaque appearance.

Transmission

The process by which incident light is emitted through a material or object.

Transmittance (of light)

Fraction of light emitted at a given wavelength that is neither reflected nor absorbed, but which passes through a material or object.

Transparent

Adjective describing a material that transmits light with minimal scattering or dispersion. Term for a non-opaque appearance.

Trapping

Prepress technique allowing slight variations in registration during printing on press.

Trichromatic

Adjective designating three stimuli, generally used to describe the components required as part of an additive synthesis to evoke a particular sensation of color.

Trichromatic components

In an additive trichromatic synthesis, quantity (expressed as a percentage) required of the three components necessary to match a color. In the CIE system, these components are designated by the letters X, Y and Z. The illuminant and standard observer used must be specified. Otherwise, the match is based on the following hypothetical values: normalized observer from 1931 (field of view of 2 °) and illuminant C.

Natural color image (24 bit color)

Digital chromatic model using eight bits for each of the three additive colors (red, green and blue), and capable of reproducing, for each color, 256 shades. Each pixel contains 24 bits, which represents 16.7 million colors. Eight bits (equivalent to one byte) are assigned to each of the red, green, and blue components of a pixel.

Natural color

Generic name for a 24-bit color.

Natural color image (24 bit color)

Digital chromatic model using eight bits for each of the three additive colors (red, green and blue), and capable of reproducing, for each color, 256 shades. Each pixel contains 24 bits, which represents 16.7 million colors. Eight bits (equivalent to one byte) are assigned to each of the red, green, and blue components of a pixel.

Turbidity

Reduction in the transparency of a sample due to the presence of undissolved material.

TWAIN

An industry standard governing how certain devices, such as scanners and digital cameras, communicate with software programs.

U

Ultraviolet

Radiant energy with a wavelength less than 380 nm. Portion of the electromagnetic spectrum between approximately 10 and 380 nm.

Ultraviolet (UV) brightener

Dyes that absorb ultraviolet radiation and then re-emit a portion of the UV energy in the form of visible light in the blue region of the spectrum. A paper thus appears lighter and less yellow. UV reflectance is not detectable by the human eye. In contrast, papers associated with a large amount of brightener can be detected using black light or a spectrophotometer.

Ultraviolet (UV) ink

Ink containing acrylic derivatives and photoinitiators that trigger the drying process when the ink is exposed to ultraviolet rays.

Ultraviolet (UV) light

Radiant energy emitted at wavelengths slightly shorter than those of the visible spectrum.

Ultraviolet (UV) protective glaze

Acrylic sheet used in the art of framing, which incorporates ultraviolet light inhibitors capable of filtering 99 % UV rays causing degradation of prints.

Ultraviolet (UV) resistance

Ability of an object not to deteriorate under the effect of UV radiation, including daylight.

Under Color Removal (UCR)

The process of removing equivalent amounts of yellow, magenta, and cyan from neutral shadow areas, and replacing them with black ink in the black separation. See also GCR.

Uniform chromaticity diagram

Declination of the CIE chromaticity diagram where all pairs of colors of equal luminance exhibiting barely perceptible variation are represented by pairs of dots arranged at nearly identical intervals.

Uniform color space

Color space in which the equivalent numerical differences correspond to equivalent visual differences, regardless of position in space. Colourists have tried for many years to develop a truly uniform color space. Without being perfectly uniform, most color spaces are said to be uniform because they are closer to uniformity than the chromaticity diagram.

Unsharp masking

Process used to accentuate images.

Unzip

Operation consisting in decompressing a file.

Load

Operation consisting in sending a file to a hosted host or to another machine.

V

Value (in Munsell's system)

A color attribute in the Munsell Color Ordering System that indicates the brightness of a sample seen in daylight, on a scale of 0, for ideal black, to 10 for ideal white, in approximately equal increments visually .

Variable data printing

Digital printing application where documents can be personalized during the printing process using data from an image or text database.

VCD (Video CD)

Full digital animation format on CD-ROM applying MPEG-1 video compression and incorporating a control bar that contains controls similar to those of a VCR.

Vector image

Image represented by mathematically defined shapes, such as lines, polygons, text, and groups of objects, as opposed to bitmap images. Another term used: “line drawings”.

VGA (Video Graphics Array)

Display standard producing 640 x 480 resolution with 16 colors.

Viewing booth

The color varies depending on the type of light it is exposed to and the surrounding colors. The viewing booth reproduces an environment that conforms to standard viewing conditions, allowing you to simulate different lighting environments in applications where color is critical.

Viewing booth

The color varies depending on the type of light it is exposed to and the surrounding colors. The viewing booth reproduces an environment that conforms to standard viewing conditions, allowing you to simulate different lighting environments in applications where color is critical.

Virtual memory

A type of hard drive space that mimics real memory (random access memory or RAM).

V-RAM (Video Random Access Memory)

A special type of random access memory (RAM) that allows simultaneous reading and writing, and which can send information to the screen at the same time as it receives new data from the video processor.

Visual spectrum

Part of the electromagnetic spectrum between 380 nm and 700 nm, which is visible to the human eye.

Acceptability volume

Acceptability volume is used to represent the location of acceptable assays in a given color space. It is a three-dimensional region that surrounds a standard and is defined by tolerance values. If a trial falls within this volume, it is acceptable against the tolerance criteria. If it falls outside this volume, it is unacceptable according to the tolerance criteria.

VRML (Virtual Reality Modeling Language)

A programming language that supports the animation of virtual spaces on web pages.

W

.wav

Audio file format used for storing and transmitting sound files, characterized by the .wav file extension.

Washing

Cleaning of ink and dampening system when changing ink colors.

Watermark

Faded inscription positioned in the background of a printed output or included in a digital file, used for security purposes (on banknotes or checks, for example) or to identify the original author of 'a picture. Identifying mark or symbol incorporated in the medium on which a work is reproduced, and which generally designates the manufacturer of the medium.

Wave length

Peak-to-peak distance of two consecutive waves.

Rotary

High speed printing press that prints on both sides of a continuous roll of paper. Presses are used for high volume print runs, such as daily newspapers and magazines.

White

Result of the combination of the additive primary colors (red, green and blue). In subtractive synthesis, white is the result of the absence of color.

White balance

Balancing of color components to create pure white when shooting or scanning a white object. Alternative to color temperature.

White point

The color and intensity of the brightest white in a device. With printers, this is often the white of the paper. With scanners, color producing values of 255, 255, 255 (RGB) when scanned. Ideally, the white point corresponds to a reflectance or neutral transmittance of 100 %.

Absolute white standard

White physical standard of a material with imperfect diffusion capacity, such as white ceramic, calibrated against the perfect diffuser.

Whiteness

Attribute used to evaluate the color of an object in relation to the preferred white.

Fluorescent broadband

A generic term for fluorescent lamps (cold white and warm white, for example) that produce broad bands of visible light relative to their phosphorescent mixture.

WAN (Wide Area Network)

Network that covers a large geographic area and typically involves lower speeds than a local area network (LAN).

Workspace

Common color space covering different workflows and ensuring accurate color matching between input and output.

WYSIWYG

Acronym for "What You See Is What You Get" (literally, "what you see is what you get") and refers to a display interface that reproduces on a screen the appearance of fonts and images. times printed.

X

X

One of the three trichromatic components of CIE, in this case, the primary color red.

XGA (Extended Graphics Array)

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

XML (eXtensible Markup Language)

A subset of SGML, the purpose of which is to provide support for SGML on the Web, in the same way as HTML.

X Y Z

Complete set of tristimulus components that numerically describe a color, calculated based on ASTM E308-85.

xyY (chromaticity coordinates)

Non-uniform color space in which the colors lie in a three-dimensional system of rectangular coordinates. x and y relate to the chromaticity (hue and chroma) of a color. Y is the brightness (lightness or brilliance) of a color.

Y

Y

One of the three trichromatic components of CIE, relating to reflectance or light transmittance, in this case, the primary color green.

Z

Z

One of the three trichromatic components of CIE, in this case, the primary color blue.

Welts

Function allowing to identify the zones of a screen presenting an excessive brightness, or too marked. When the shine reaches a certain degree, the welts will appear over that area to indicate that it may be too light. These welts are simply a series of black lines that oscillate in a disturbing pattern. And even if you didn't know the term before, the pattern displayed will look familiar.

Zipper

Operation consisting in compressing a file.

Zoom

Enlarging a portion of an image.