pantone guide updates...pantone® colors, paper color, tonal value increase, gray balance, and ink...

Ink

Printing process Substrate

Specifications

PANTONE GUIDE UPDATES

Since the PANTONE PLUS SERIESwas launched back in 2010, three color collections have been updated.

Since 2010, 756 color palettes have been added to the guide.

December 2017 · No. 4

Business Unit Sheetfed

COLOR NEWS

Siegwerk France S.A.S. · F-74105 Annemasse / France · Business Unit Sheetfed – Center of Competence · Tel. +33 450 87 74 00 · www.siegwerk.com

From the color selection to the finished printing product, many criteria can influence the colored result. The process is quite complex. Each element in the graphic chain will have to combine requirements and technical constraints in order to guarantee the color required on the substrate by the brand owner.Sometimes it can be difficult to reach the target color due to tech-nical constraints (specifications, material, etc.). If the colorist has to match a bright color on an absorbing paper or on recycled paper, it is almost impossible to get the freshness and brightness of the required shade because of the paper’s porosity. Often, there is confusion between color and aspect. The aspect takes into account the gloss, texture, and the nature of the material which we unfortu-nately are unable to reproduce through a colored ink.Sometimes, colorists have to develop pastel colors on a greyish substrate. Furthermore, color formulas have to be light resistant.In the case of a transparent ink, the color of the substrate is revealed through the printed ink layer. If the ink is very clear, the color of the substrate is revealed to a greater extent. Additionally, a lightfast pigment is generally duller than a pigment that is non-lightfast. In this case, colorists are faced with three problems which limit the ability to match the target color.

Color beyond technical constraints

The visual result of a printed color depends on a multitude of parameters that have to be anticipated as soon as the product is created. All colors and desired aspects are not feasible on press. One solution is to use PantoneLive. PantoneLive offers color standards which are more in line with industry since they depend on the print-ing process and ink technology and are based on current and varied material ranges (cf COLOR NEWS No.3). The ink manufacturer is also an essential contact who can recommend the most suitable ink series and offer the best compromise for the desired application, taking into account the specifications, type of substrate, and the inks.

Specifications

• fastness: light…• food packaging• varnishing/laminating• sterilization

Printing Process

• ink film thickness• mechanical aspects• chemical interaction• drying conditions

Substrate

• intrinsic color• whiteness• opacity/transparency• porosity/absorption• aspect: metalized…

Ink

• Pigment (origin, grinding, concentration)• Selection of a suitable ink range, which meets all technical requirements

1- Transparent and light Ink

2- Substrate greyish

3- Lightfast pigment use: duller/dirtier

New color Guide Colors added Total colors Colors missing from your last guide update Launch dates in the Guide

2010 224 1341 If you haven’t updated in the last 6+ years- you’re missing 756 colors

2012 336 1677 If you haven’t updated in the last 5 years- you’re missing 532 colors



In offset printing shops, density control is essential. By measuring the densitometry of the full tones, the operator can identify the film thickness variations of the ink applied on the substrate and readjust the quantity of ink accordingly.With the 4-process color system, the densities CYAN, MAGENTA, and YELLOW have to be particularly stable so that the colors RED, GREEN, and BLUE (obtained by superposition of two primary colors) are well balanced.Moreover, BLACK injects a contrasting effect to the image.



COLOR NEWS

Why measure density?

Dry and wet ink surfaces reflect light differently. Freshly printed ink has a smooth surface like a mirror. As a result, density measure-ment indicates a higher value. When drying, the surface of the ink adopts the irregular structure of the paper. Density measurement indicates a lower value compared to wet ink.

Typical values of densities, conventional inks, full tone, independent of ISO12647-2 certifications

DO = log (I0 /IR) I0: Incident Light

IR: Reflected Light

INK

WHITE LIGHT

RECEPTOR

FILTER

IR

Io

MATERIAL

Filters are automatically setup according to the color measurement:

Filter Green to measure MAGENTA DO Filter Red to measure CYAN DO

Filter Blue to measure YELLOW DO

3.00 5.50 8.00

10.50 13.00

0.7000 0.9000 1.1000 1.3000 1.5000 1.7000 Grammage

Colorimetric deviation DE*

1

2

0.6000 0.8000 1.0000 1.2000 1.4000 1.6000

Optical Density

The two figures are chromatically

balanced, but the densities of the

fulltone surfaces are different.

Here, the densities are uniform, but

the color balance is not respected

because of the dot gain.

To remove the surface influence on the results, we recommend using the polarization filter for density measurement. Thanks to this filter, waves can only pass in one single direction. We can also measure density of halftones. In this case, the mea-sured reflectance corresponds partly to the light reflected by the dot screen and partly to the light reflected by the substrate.From the halftone densitometry, it is possible to deduce the per-centage of coverage, thanks to the Murray-Davies equation. The result gives the proportion of the total area covered by the dots.

Today, in the printing industry, the ink layer or density adjustment is closely linked to the colorimetric control of the ink.

Indeed, since the start of PSO standards right up until the last update (12647-2: 2013), printers rely on the process color L*a*b* values to calibrate their press and certify their printing process (density, dot gain, color superimposition, etc.).

Based on the kind of substrate, the printer selects the suitable colorimetric values from the PSO standard. Once the color deviation (DE) is optimized on the test print, the optical density is measured and becomes the new target for subsequent jobs. Density and colorimetry are both linked to the ink layer. By increasing the ink charge, the densitometric and colorimetric variations are clearly visible. However, beyond a certain inking threshold, the density reaches its maximum, or saturation. So, the density control cannot substitute the spectral measurement to evaluate the color deviations.

Colorimetric or densitometric control?

Ex: P. Magenta

applied at several ink

layers [0,7;1,5] g/m²

Target values

ISO2846-1

Magenta turns yellowish

when the ink film thick-

ness increases. The color

is moving farther away

from standard target

values.

In terms of densitometry,

saturation is reached

around 1.10 g/m²

(density value = 1.70)

We have discussed how optical density is related not only to the ink, but also to the printing conditions like press, substrate class (glossy coated, matt coated, uncoated, synthetic, etc.), blankets, printing plate, dampening characteristics, deposit, etc.

Source: System Brunner

IR is always less than IO. Thus, the optical density is always positive. Its value increases as the surface absorbs light (that is, the ink layer is thick, or is highly pigmented).

To measure the density of a printing, we use densitometer by reflection. Density is a function of the amount of reflected light.

Typical values of densities, conventional inks, full tone, independent of ISO12647-2 certifications

The densitometer is a measuring instrument that is equipped with three filters.* This device captures the reflected light through the ink film to determine the density of the ink, the dot gain, and the trapping from the control chart. Unlike the spectrophotometer, the densitometer doesn’t measure color.

The spectrodensitometer is more efficient because it combines densitometric and spectral measurement (colorimetric). Thirty-one points are instantly measured between 400 and 700 nm.



COLOR NEWS

Densitometer & Spectrodensitometer

On our plate, the lobster has a beautiful orangey red color. However, before going into the pot, the carapace of the animal is a dark blue, so a color transformation takes place that has been puzzling scientists for decades. But now an international team has identified the chemical process behind this transformation.

Researchers already knew that the carapace of lobsters is rich in astaxanthin. This orange pigment in the carotenoid family is found in different crustaceans, plankton, certain micro-algae, and fish such as salmon, or even in bird feathers. For lobster, it interacts with a protein called crustacyanin to give the blue color that helps the animal hide from its predators. But when cooked, the protein disintegrates because it is not heat-resistant and thereby releases the astaxanthin which, as a result, becomes orange again.

Source: Sciences et Avenir

SpectroDensitometer eXact: A touchscreen and portable colorimetric instrument. Ideal for controlling process prints that require a variety of traditional tools, while retaining the ability to add more features as needed.

Automatic reading system IntelliTrax2:Analyzes the control range of a typical print sheet in less than ten seconds. Measures process colors, spot colors, PANTONE® colors, paper color, tonal value increase, gray balance, and ink density.

Prinect Image Control 3:Allows the simultaneous control of the full printed image and inking correction online in all print groups.

SpectroDensitometer FD-7:Allows color measurement by considering the fluorescence contained in the paper under any illuminant, including D50 (M1).

Automatic chart reader FD-9:Only four minutes are required for the FD-9 to measure a chart composed of 1500 patches, from the insertion of the printed chart to the measured data display. With the FD-9, lots of data* can be obtained in a single measurement.

*under multiple measurement conditions (M1, M0, M2)

X-Rite

Heidelberg

Konica Minolta

Did you know? Why do lobsters change color when cooked?

What is extended gamut printing?Printing in expanded or extended gamut means that the package is printed by superposition of a CMYK + two or three additional ink combinations (orange/green/blue) in order to replace spot colors. About 50% of PMS colors would be achievable in 4 color process. The ink’s addition to the classical range CMYK enables printers to achieve a larger color panel and better quality.

Multiple equipment is needed for prepress to analyze and decompose the image and to reproduce it in a multichrome way. Equinox™ is one of the solutions proposed by Esko, which manages the shades conversion to CMYK or to extended gamut. According to the printing process and prerequisites, CMYK printing can replace some or all of the spot colors. The software predicts the gamut’s ability to convert the spot colors accurately, whatever the ink set. With this kind of system, printers don’t have to change spot colors during and after each packaging production. This allows them to increase the productivity of their presses, while reducing ink costs.

However, in offset, it is more difficult to substitute an ink for-mulation by superimposing and juxtaposing points of several primary colors. Just a small variation in the inking (density), dot gain, or trapping will definitely change the color.Due to technical constraints, the matching of spot colors through a multichrome system (halftone) is tricky, especially as the brand owner’s color requirements are very strict.

In UV flexo, the printing process and trapping problems are much less critical thanks to the systematic inks drying inter- group. There is no longer an issue due to emulsion (dot gain), and inking variations are lower. Halftone printing is more reproducible and feasible because there are fewer machine setting fluctuations.The feasibility of multichrome jobs is related to the printing process and also to the level of colorimetric expectations.

Topic to follow in the next edition of COLOR NEWS



COLOR NEWS

The benefits of extended gamut

Gamut: This is a color set which is reproducible with a certain equipment: camera, computer screen, printing process, etc. It is represented as an envelope in a 3-axes system. A process of color synthesis cannot reproduce all the colors visible to the human eye. The basic colors used are crucial since the size of the gamut will depend of them.

Two areas are represented below. The «process colors» gamut (the core) is compared to the extended «process + 2 colors» gamut (outer envelope). The scatter plot represents Pantone formulations made in the sheetfed department. By working in hexachromy, the envelope is wider. This system makes it possible to cover more PMS shades in the «Orange» and «Green» zones.

The Colibri® system by Konica Minolta offers an equivalent «3D gamut viewer» tool for viewing color recipes, ink ranges, and standards libraries in the 3D CIELAB color space. It displays the true color envelope and color dots, allowing operators to track the color path, to identify and reduce the number of similar products in a range, to spot gaps in the color space, and to visualize which color can be achieved with process inks or with hexachromy.

Screen shots realized with the 3D viewer tool - IFS6.3 -Xrite.

Gamut Process Colors Gamut Process Colors + Orange + Green

Gamut Process Colors Gamut Process Colors + Orange + Green

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