Color trapping is necessary to compensate for poor color registration that occurs when the printing plates used to print each color, called color separations, are not aligned perfectly. Poor registration causes unintentional white slivers to appear between adjoining colors. Trapping is accomplished by intentionally overlapping colors so that minor problems with alignment are not noticed.
The print job needs color trapping when two colors touch. Many service bureaus prefer to create color traps themselves by using specialized trapping programs. Consult the service bureau about trapping if you are unfamiliar with the process.
An example of an image printed with and without color trapping
Color trapping is achieved by overprinting. Usually, portions of an object that are obscured by another object are not printed. However, if the top object is set to overprint, the obscured portions of any underlying objects print anyway, causing an overlap. This makes white gaps between different colors unlikely. Overprinting works best when the top color is much darker than the underlying color; otherwise, an undesirable third color may result (for example, red over yellow may result in an orange object).
Depending on the color trapping options you choose, overprinting may affect only an object's outline or fill. This means that if an object with a red outline is set to overprint only its outline, any portions of another object obscured by the first object's outline are printed. The overlap creates a color trap.
• Although CorelDRAW is capable of basic trapping, specialized trapping applications such as Imation TrapWise can provide you with a more complete trapping solution.
Was this article helpful?