Archive for August 9th, 2017
Color Trapping
Wednesday, August 9th, 2017
Usually happens in Pantone color, but also happens between solid CMYK.
When two element colors are used side-by-side, there will be no problem on monitor and digital color proof because they have perfect alignment. However, there is a slight margin of error on printing and a thin white line will appear sometimes. It is illustrated at the left hand side of the following picture.
The goal for offset printing is mass production. Our Heidelberg printing machine can print up to 12,000 impressions per hour. Technology has kept improving and the alignment error between colors can be as little as approximately 0.1mm nowadays. However, our eyes can see the 0.1mm white line between solid colors if they don’t have perfect alignment.
There is a solution call trapping. The right hand side of the above picture illustrats the picture after trapping. One of the color is a overlapping the other color for about 0.1mm to cover up the 0.1mm error from the machine. The overlapping color is usually not noticeable to human eyes. Some CTP programs can do trapping automatically between spot colors but they are not 100% reliable. We can also draw an over-print color line around the shape to create trapping.