Spot color
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In offset printing, a spot color is any color generated by an ink (pure or mixed) that is printed using a single run.
The widely-spread offset Process Printing is composed of four spot colors: Cyan, Magenta, Yellow and BlacK, commonly referred to as CMYK. More advanced processes involve the use of six spot colors (hexachromatic process), which add Orange and Green to the process (termed CMYKOG). The two additional spot colors are added to compensate for the inefficient reproduction of faint tints using CMYK colors only. However, offset technicians around the world use the term spot color to mean any color generated by a non-standard offset ink; such as metallic, fluorescent or custom hand-mixed inks.
When making a multi-color print with a spot color process, every spot color needs its own lithographic film. All the areas of the same color are printed using one film, then the next film will have a different image to correctly print the next color. The dot gain, hence the screen angle and line frequency, of a spot color vary according to its intended purpose. Spot lamination and UV coatings are sometimes referred to as 'spot colors', as they share the characteristics of requiring a separate lithographic film and print run.
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Computer Methods of Generating Spot Colors
There are various methods to incorporate rather sophisticated patterns of spot colors in the final prepress artwork. Software applications like Adobe InDesign, Adobe Illustrator and QuarkXPress may generate spot colors as additional channels. Adobe Photoshop can also be used to generate soft edges (widely known as feathered edges) of spot colors. The dissolve effect provided by Adobe Photoshop layer patterns can be generated for any spot color.
Optimizing Spot Color Usage
Generally the cost and potential for problems for a print job increase as you add more spot colors, due to the increased cost and complexity of added process inks and films, and requiring more runs per finished print. However, spot colors can be a very powerful weapon in security printing, like money, passports, bonds, and other similar prints that should be hard to forge. Money printing for example, uses secret formulae of spot colors, some of which can be seen by naked eye, and some cannot be seen unless by using special lights, or by applying certain chemicals.
Can spot color be legally binding?
Experience has shown that even the most reputed companies like Pantone change mind in defining spot colors. The fact that offset printed swatches of standard color kits may discolor with time (manufacturers guarantee them for one year) proves that these books may not last forever. The latter fact means that clients' printed materials will also change with time and their standard Corporate ID will change too. There are many other reasons, such as the perfection of printing standard color swatches compared to everyday offset prints.
In other words, the clients should also state that their corporate ID distributed on advertising agencies is not a valid reference after one year due to discoloring factors. No one can ever ensure that offset printed spots will last.
Digitization of Spot Colors
Spot colors are now a great business for a company like Pantone. The modern trend in spot color matching systems is the digitization of spot colors. The idea came from the fact that a spot color print may not be 100% matching to the monitor's colors. To achieve a rather good result of simulating the RGB colors into CMYK colors in offset prints, a proper monitor calibration should be done to realize a good balance between reproduction of gray color on paper and on screen.
One important fact is that monitor colors can never be matching to the printed color, as the printed color is composed of inks, while monitor's colors are composed of color lights!
Classification of Spot Colors
Spot color classification has led to hundreds of discrete colors being given unique names. There are several industry standards in the classification of spot color systems, such as:
- Pantone, the dominant spot color printing system in the United States.
- Toyo, a common spot color system in Japan.
- DIC, another common Japanese spot color system.
- ANPA, a palette of 300 colors specified by the American Newspaper Publishers Association for spot color usage in newspapers.
Because each color system creates their own colors from scratch, spot colors from one system may be impossible to find within the library of another.
See also
Monitor Calibration (Written by: Mohamed Al-Dabbagh)de:Schmuckfarbe