The advantage of using a PowerTrapper is that you do not have to prepare the PDF file or create the trap layer in advance. In addition, you can trap the input file without an intermediate file. The output of this task is a Normalized PDF file.
You can choose your trapping settings in the Distance & Direction, Color & Shape, Processing, Rules and Output tabs.
Enter the width you want to give your traps. The unit used is the General unit defined in Illustrator's Unit & Display Performance Preferences. The default trap width is 0.2 mm (or equivalent in your chosen unit).
You can choose more trapping distance specifications such as: into black, into spot, into image and into pullback further down in this tab.
For example, with the default minimum ink difference percentage of 10%, the following two colors are trapped:
1st color: C 5% M 10% Y 50% K 15% (+10% K)
2nd color: C 5% M 10% Y 85% K 5% (+35% Y)
Increase the Minimum Ink Difference to trap colors that differ more, lower it to trap colors that are similar.
If you want images to be trapped with each other, enable Trap images to images.
You can use ink pull back to keep away all but the darkest ink of a color area composed of multiple inks bordering to a very light background. It prevents individual inks from the composed color to become visible on the background due to registration errors during the printing process.
There will be automatic pull back for the darkest color. You can enable Also pull back light inks option to create pull backs even when the pullback ink (ink remaining in the pull back area) is visibly different from the composed color. Enable Pull back images and gradients to create pull backs on images and gradients.
You can enable this option to set the trapping direction by ink sequence. PowerTrapper uses the color luminance to define the trapping direction by default except for opaque inks. PowerTrapper uses ink sequence to determine trapping direction in the case of opaque inks. If the Treat all spot colors as opaque inks option is enabled, color luminance is used only for CMYK. For opaque and spot inks, the trap direction is determined by the ink sequence.
By default, PowerTrapper uses the full color of the object to spread in the trap (100% trap color intensity).
You can create a trap of a lighter color by reducing the trap color intensity percentage.
The miter ratio serves to limit the length of the sharp corner (the distance from the base of the trap to the corner point).
The default miter ratio value is 4. This means that if the length of the sharp corner is more than 4 times the Trapping Distance, then the corner are cut off (beveled). If it is less than 4 times the Trapping Distance, the corner are left as it is.
Click the collapsible button to show the advanced settings.
Truncate Traps
If you want to truncate traps into black differently, select Into black and choose the truncation mode (On Center or On Edge).
The default size is 1 mm (or equivalent in your chosen unit).
Some input jobs contain very small unintentional gaps between neighboring objects, preventing the correct trapping of these objects. Although it is better to clean up such jobs before trapping, PowerTrapper can ignore these gaps automatically.
To use this option, select Close when smaller than and enter the maximum size small gaps can have.
The unit used is the General unit defined in Illustrator's Unit & Display Performance Preferences.
In most cases the general trapping settings entered in the Distance &Direction gives you excellent results. You can refine them using rules. If you add a rule that is not coherent with your inputs in the other tabs, PowerTrapper will overwrite them with the rules
You can specify exceptions to the general trapping settings for certain color pairs using Add Rule. Some of the instances where you can use it are :
When trapping your document, PowerTrapper traps the trapping pairs that match rules according to those rules and the rest of your document according to the main trapping settings. If necessary, you can add another rule or remove a rule previously created. You can also edit a rule by double-clicking it in the Rules tab.
You can specify the output at Output tab. You can enable Trap layer only or Load trap color pairs if present or enable both
See also: What is trapping?