Color reproduction in printing processes is a complex challenge, especially when special color systems like RAL, HKS, Pantone, and NCS are involved. These systems offer standardized color palettes that require precise reproducibility to meet the demands of designers, architects, and businesses. The expansion of the classic CMYK color space with Light Magenta (LM) and Light Cyan (LC) provides additional opportunities to reproduce these special colors with even greater precision.
Basics: CMYK and its extensions through LM and LC.
The classic CMYK color space
CMYK stands for Cyan, Magenta, Yellow, and Key (Black). This four-color process is the foundation for most printing techniques. Each color is represented by the combination of halftone dots at varying densities, creating a wide color spectrum.
Extension through LM and LC.
Light Magenta (LM) and Light Cyan (LC) are lighter variants of Magenta and Cyan. These additional inks expand the color gamut and offer the following benefits:
- Smoother Transitions: Especially with pastels, skin tones, and light color gradations.
- Finer Details: Reduces dithering and smooths gradients.
- Expanded Gamut: More realistic reproduction of colors difficult to achieve in standard CMYK.
An overview of the special color systems:
RAL, HKS, Pantone, and NCS
In the world of printing and color design, special color systems like RAL, HKS, Pantone, and NCS play a central role. These color systems were developed to represent colors in a standardized and consistent manner, ensuring they can be reproduced exactly regardless of material, printing method, or lighting. Whether in industry, graphic design, or architecture – special color systems provide the precision and reliability essential for both creative and technical projects.
1. The RAL color system
Background
The RAL color system was introduced in 1927 by the German Institute for Quality Assurance and Certification e. V. and is one of the oldest and most well-known color systems worldwide. RAL stands for Reich Committee for Delivery Conditions (dt. Reichs-Ausschuss für Lieferbedingungen) and includes a standardized collection of colors that were originally developed for industry.
- RAL Classic:
- It contains 213 colors, including standard colors such as RAL 9010 (Pure White) or RAL 7016 (Anthracite Grey).
- Primarily used in architecture, construction, and the automotive industry.
- RAL Design:
- Offers over 1,600 colors, organized according to a scientific system (Hue, Lightness, Chroma).
- Ideal for creative design and applications that require a broader color range.
- RAL Effect:
- It contains 490 solid colors and 70 metallic colors.
- It is often used in coatings and painting applications.
Applications
- RAL colors are widely used in the industry, in painting, coatings, and material selection in architecture.
- The standardization ensures consistent color reproduction, regardless of material or production location.
2. The HKS color system
Background
The HKS color system was specifically developed for offset printing and is a color library containing 120 base colors as well as over 3,000 mixed colors. It represents the collaboration of three companies: Hostmann-Steinberg, Kast + Ehinger, and H. Schmincke & Co.
Features
HKS colors offer particularly brilliant and opaque color effects, as they are made from specially formulated pigments.
- Unlike CMYK inks built from halftone dots, HKS colors are spot colors—making them ideal for logos, packaging, and corporate design.
Color systems within HKS
- HKS K: For coated paper.
- HKS N: For uncoated paper.
- HKS Z: For newsprint.
- HKS E: For continuous paper.
Applications
HKS is preferred in print media where precise and brilliant color reproduction is crucial, such as in brochures, business cards, or packaging.
3. The Pantone color system
Background
The Pantone Matching System (PMS) was developed in the 1960s and is now the global standard for color matching in graphic design, the printing industry, and fashion.
Color Collections
Pantone Formula Guide:
Contains over 1,800 colors displayed on coated and uncoated paper.
Pantone Metallics and Pastels:
An addition for special applications, such as packaging or exclusive print products.
- Pantone Fashion, Home + Interiors:
A separate color library for textiles and plastics.
Characteristics
Pantone colors are spot colors based on precise pigment mixtures.
Each color is defined by a unique number, making communication between designers and print service providers easier.
Applications
Pantone is frequently used in branding and corporate design, where exact color reproduction is essential. Logos, packaging, and promotional materials benefit from the high precision and consistency.
4. The NCS color system
Background
The Natural Colour System (NCS) is based on human color perception and was developed in Sweden in the 1970s. It classifies colors based on their visual properties and allows each color to be described unambiguously.
Properties
Colors are defined by six primary colors: white, black, yellow, red, blue, and green.
Each color is described by its hue, brightness, and saturation.
The system includes more than 1,900 standardized colors.
Applications
NCS is preferred in architecture, interior design, and product design.
Due to its scientific approach, it is particularly helpful in color selection and coordination with different materials.
The Challenges of Special Color Reproduction
Special Color Systems and Their Properties
- RAL: An industrial color system based on durable, consistent shades.
- HKS: Designed for offset printing, delivers vibrant spot colors difficult to replicate with CMYK.
- Pantone: A global standard with a wide range of precisely defined colors.
- NCS: Scientifically grounded, focused on human color perception.
Each system defines colors independently of print limitations. The challenge lies in representing these within the CMYK color space, constrained by ink properties.
Color Management and RIP Software
The translation of spot colors into CMYK + LM/LC requires powerful color management systems:
- ICC Profiles: Optimize the reproduction of specific colors across different printers and materials.
RIP Software (Raster Image Processor): Converts spot colors into CMYK values and uses the additional inks (LM and LC) to expand the gamut.
The reproduction in the CMYK color space of the spot color systems in detail
1. Reproduction of RAL colors
RAL Classic: These colors are relatively easy to represent in CMYK, as they often rely on clearly defined primary and secondary colors.
- The additional LM and LC inks enhance transitions and lighter tones.
RAL Design: The larger color palette requires more precise color matching, as many shades lie outside the CMYK gamut. LM and LC can help simulate more subtle hues.
Features: UV direct printing and HP latex printing are well-suited for representing RAL colors, with material and surface texture potentially influencing color reproduction.
2. Reproduction of HKS colors
HKS colors are spot colors that are often simulated in CMYK printing.
LM and LC enable better representation of lighter HKS tones, reduce grain, and improve transitions.
Challenge: Due to the high brilliance of HKS colors, some shades are difficult to reproduce exactly. Color management tools play a crucial role here.
3. Reproduction of Pantone colors
Pantone colors can be printed directly as spot colors or simulated in CMYK.
The use of LM and LC expands the color gamut and allows for a more accurate approximation of Pantone colors that are difficult to reproduce in the traditional CMYK system.
Example: Pastel shades like Pantone 698 C are represented softer and more realistically through LM.
4. Reproduction of NCS colors
- The NCS system is based on color perception, making exact print reproduction challenging.
- CMYK + LM/LC helps better represent the complex nuances and transitions of NCS colors.
Application: Particularly in architecture and interior design, where precise color nuances are required, such as for wall coverings or wallpapers.
Technical Aspects in UV Direct Printing and HP Latex Printing
UV direct printing.
- Advantages:
- Capability to print on rigid materials like glass, metal, or wood.
- Instant ink curing for durable results.
Challanges:Limited color gamut due to the chemical properties of UV inks.
Material surface affects color reproduction.
- Additional Colors: LM and LC enhance special color reproduction, especially on light or textured surfaces.
HP latex printing
- Advantages:
Water-based inks that are environmentally friendly and odorless.
- Ideal for flexible materials like textiles or films.
Larger color gamut compared to UV printing.
Challanges:Color deviations on highly textured surfaces.
- Additional Colors: LM and LC enable smoother transitions and more realistic reproduction of spot colors on flexible materials
Conclusion: Special color systems and their reproduction in digital printing
Reproducing specialty color systems like RAL, HKS, Pantone, and NCS in the expanded CMYK color space (CMYK + LM/LC) is a technological feat requiring precision and expertise.
Extended CMYK Inks: LM and LC expand the displayable color gamut and improve the reproduction of light and subtle tones.
Spot Colors: With the help of modern color management tools and RIP software, spot colors can be efficiently converted into CMYK values.
Printing Techniques: UV direct printing and HP latex printing offer versatile options for accurately displaying colors on various materials.
