Lexicon

Calender is the term used to describe several steel rolls, which are usually heated and between which materials are passed and thus “calendered”, i.e. smoothed, rolled, thinned etc.

In thermosublimation printing, the print is transferred from a transfer paper to the material to be printed on a calender by passing both of them through the calender in superimposed layers. Through heat and pressure, the colour pigments on the paper explode and the colour bonds permanently with the fabric.

Calendering is also called “satin-finishing” in paper manufacturing. Paper is mechanically smoothed between the calender rolls to produce coated or uncoated paper. Calendering takes place under very high pressure and temperature.

Calender is the term used to describe several steel rolls, which are usually heated and between which materials are passed and thus “calendered”, i.e. smoothed, rolled, thinned etc.

In thermosublimation printing, the print is transferred from a transfer paper to the material to be printed on a calender by passing both of them through the calender in superimposed layers. Through heat and pressure, the colour pigments on the paper explode and the colour bonds permanently with the fabric.

Calendering is also called “satin-finishing” in paper manufacturing. Paper is mechanically smoothed between the calender rolls to produce coated or uncoated paper. Calendering takes place under very high pressure and temperature.

CAT is short for Cromatic Adaptation Transform.

Chromatic adaptation means that the human eye performs an automated white balance. Colour is thus perceived quite independently of the colour temperature.  The CAT algorithms are based on scientific insights into chromatic adaptation for different light and colour combinations.

Committee for Graphic Arts Technologies Standards.
A standardization group that develops various standards for the US printing industry. The standards concern printing, colour conversion and much more.

Chromo board refers to a multi-layer type of cardboard with a coated, usually white front side and an uncoated back side. It is very resistant to bending, splitting and peeling and can be easily scored, die-cut or grooved.

During production, the front side is coated several times, whereby the top layer of chalk, pigments and binders ensures a smooth, glossy surface with excellent printability.
The mostly uncoated reverse side, on the other hand, is made of recycled pulp or bleached mechanical pulp, which makes it less printable but very easy to write on.

Chromo board is mainly used for packaging printing (boxes, book and brochure covers, etc.) but also for postcards, flyers or folders.
Chromokarton can also be used for archiving, as it is very light and age-resistant, if produced acid-free.

One-side coated paper with excellent printability.

It is coated with a water-resistant, high-quality coating dispersion, whereby the surface can be both matt or high-gloss.

Chromo paper is preferably used as covering paper on puzzles, posters, displays or premium packaging, but also for labels or book covers and brochures.

The CIELAB colour model was defined in 1976 by the Commission Internationale de l’Eclairage and describes all colours that can be perceived. It is a mathematical colour model in which the spectral properties of an object and the perceptual properties of our visual system are set off against each other. CIELAB, or in short: LAB, has become generally accepted until today wherever exact colour calculation is required, whether in colour measurement, colour formulation or in the common operating systems: Colour management usually works via CIELAB.

CMYK stands for the four printing inks Cyan, Magenta, Yellow and “Key” (Black) . These four inks are the base of four-color printing. For printing colorful photos at least these four inks are required.

CMYK color spaces depend on the printer and the paper used and therefore need color profiles to describe the exact shades.

The main CMYK color spaces are:

ISOcoatedv2
PSOUncoated
GRACol
SWOP

Color proofs (correct: contract proofs) are an ISO-certified test equipment for the graphic arts industry. Color proofs simulate the colorfulness of offset or gravure printing in a color and legally binding manner within the narrow tolerances of ISO 12647-7. Today, they are almost exclusively calculated using a RIP and then produced with inkjet printers on special proof papers.

The proof data is converted into separations, then reassembled into a composite image to correctly simulate overprinting and trapping. The data is then transferred as a newly created composite image to an inkjet printer, usually with more than 8 colors, which prints the data. In addition to the print data, digital proofs must also carry a UGRA/Fogra media wedge in order to be color-consistent and legally binding. Thanks to the standardised wedge, the printer is able to check the proof for correctness. Since many printing houses do not have this measuring technique at hand, the proof is often provided directly with a test report that shows the correctness of the measured values of the media wedge directly on the proof.

Earlier methods such as Chromalin etc. are no longer available on the market today.

In addition to the term “color proofs”, terms such as digital proofs, proofs or online proofs are still in common use.

ISO 12647 defines the highest standard of contract proofs, or “proofs” (ISO 12647-7), as well as the term “validation prints” (ISO 12647-8). Validation Prints are characterised by the fact that although they are less accurate in color, they can also be produced on laser printers. Compared to contract proofs, however, they accept much higher color deviations and are only legally binding after prior consultation. Real “proofs”, i.e. true contract proofs according to ISO 12647-7 are currently not only by far the best variant in terms of color but also the only legally binding proofs.

Further information:
https://en.wikipedia.org/wiki/Prepress_proofing

A colour measuring device for measuring/comparing colours.
It is often used for the calibration of monitors or in biology/chemistry for analysis. More powerful devices, such as the spectrophotometer, can measure colours spectrally and are also used, among other things, for proofs to verify or calibrate printers.

Colorimetry, or colour theory, is the science of colour.

It includes:

• the perception of colour by the human eye and brain
• the origin of colour in materials
• the theory of colour in art
• the physics of visible light

Colorimetry is primarily concerned with an objective and measurable evaluation and definition of colour valences (the visual perception of colour), as well as their relationships to one another.

When a coloured image appears as if a coloured filter is placed over it, this is called a colour cast. In printing, this is caused by a poor gray balance.

Specifies how many different colour shades can be displayed.
It is based on the binary system that all PCs use.
A colour depth of 1 bit would mean that 2 colours can be displayed, whereas 24 bit = 16.7 million displayable colours.

The colour depth has a direct influence on the file size.

The measured distance (colour difference) between two colours. The colour locations of the two colour values are displayed within a system and the difference is given in Delta-E.

The colour gamut (or simply: gamut) refers to the range of all colours in a colour space that can be recognised (camera, scanner) or reproduced (printer, monitor) by a device.
It is visualised in the form of a colour solid.

The colour location describes the position of a measured or selected colour within a colour space. This is often defined by coordinates, e.g. using L, a and b in the CIELab colour space.
The set of all the colour locations in a colour space is called the colour gamut (or gamut).

With colour management it can be achieved that colours on different devices like cameras, scanners, monitors, laser, inkjet, offset printers and many more can be reproduced as similar as possible to each other.

Therefore device-dependent colour spaces must be used. A well working colour management will map the gamut of each device as Monitores and printer and device-independent colour spaces such as Adobe RGB 1998

Modern colour management systems use instruments such as the X-Rite i1 Pro 2 and related colour management software that creates and manages colour profiles within application programs such as the Adobe product range provides.

Colour measurement is used to determine the exact colour location of a colour in a colour system.

There are three methods:

The Tristimulus Method:
A tristimulus colourimeter shines an internal light source onto the surface of the colour sample.The reflected light passes through three filters – red, green and blue – which determine the intensity of these color components.
The reflected light passes through three filters – red, green and blue – which determine the intensity of these colour components.

The Spectral Method:
A spectrophotometer works in a very similar way – but has not only three, but 31 filters that measure 31 different wavelengths of the reflected light. Thus the spectral method is one of the best methods for measuring colour.

Equality Method:
Here, a measuring device (or the eye) is used to compare the colour sample with standard colour samples until all samples are considered identical by the observer. However, this is assessed subjectively by the viewer, which is why the other methods of colour measurement are preferred in practice.

The colour mode is a setting that determines the depth to which colours can be displayed in an image file. This also affects the size of the file.

The most common colour modes are:

• RGB mode (millions of colours)
• CMYK mode (colours for four-colour printing)
• Lab/CIELab
• Index mode (256 colours)
• Grayscale (256 shades)
• Bitmap (2 colours: Black or white)

A colour model (or colour system) is an abstract mathematical method for determining and specifying colours and their relationship to each other.
It is sometimes referred to as colour space, although the latter is the concrete application of a colour model to a colour-producing method (printer, monitor, etc.).

Well-known colour models are:

• RGB (additive colour mixing with red, green and blue)
• CMYK (subtractive colour mixing with cyan, magenta, yellow and black)
• Lab/CIELab (brightness, red-green axis and blue-yellow axis)
• HSL and HSB/HSV (Hue, Saturation, Lightness and Hue, Saturation, Brightness/Value)