Trapping in QuarkXPress can be controlled in 3 ways.
1 Automatic trapping. This means that you can simply let QuarkXPress trap the output, and this method needs to be set in the trapping selection dialog.
2 color to color trapping. Trapping can be set directly to the color definition, which is more advantageous than automatic setting.
3 trapping of objects to objects. In our layout program, we use the floating Trap Info palette to change individual objects or reimplement traps. These values ​​will replace the automatic trapping values ​​and the color-defined trapping values.
Each trap should be used properly, but these three methods are rarely used together in the same document.
In general, QuarkXPress "auto trapping" equipment is sufficient, and it can be further checked or enhanced on the Trap Info palette; if "color-to-color trapping" is adopted, the automatic setting will be ignored. You can use the Trap Info palette to work according to the trapping rules you set, but you don't rely solely on "object-to-object trapping." Because there are hundreds of color objects in the file, it would take too much time to trap each object.
1. Trapping automatically
Figure 14 QuarkXPress trapping options
Automatic trapping refers to the trapping value provided by QuarkXPress, and the trapping value is not displayed in the page layout like in IIIustrator or FreeHand.
Automatic trapping is always active unless you tell it to do other work. The default trap value is always used by the page layout software to check the automatically generated settings (see Figure 14), with the following options:
1 Auto Amount (Automatically Generate Trapped Values)
This is the trap width automatically generated by QuarkXPress. This width is enough to achieve the overlay accuracy of the printing press.
Based on the printing experience, we emphasize that the setting automatically generates a value of 0.3 points. Of course, if it is a high-quality print, a high-quality printer, and an experienced operator, then the value should be set to 0.25 points. Of course, this value can also be set to 3 o'clock or 4 o'clock depending on the condition of the printing press used.
2Auto method
If Absolute is selected, each object will be trapped with the width of the auto trapping value. According to the lightness or darkness of the color, a certain proportion will be selected, and the automatically generated value will be used. It should be noted that the default values ​​in Absolute should be used as far as possible unless otherwise recommended by the printing professional.
3Indeterminate
If you are trapping a mixed high-precision scan image, or trapping in a different color, QuarkXPress simply treats it as a color. This is called color indeterminate, and it is set here by default. Trap value.
4Overprint Limit
It controls the percentage of color overprint, which is based on the settings of the trap dialog. Considering the darkness of many input images, this value is often set to 95%. If you want to trap lighter spot colors, lower this value.
5Ignore White (ignore white)
Select this tool to create all the whites that pass through a part of the object on a multicolor background when the trapping occurs. This will make the trapping lines more visible. The trapping effect depends on the current color and the direction of trapping, but care must be taken to examine all colored objects overlaid on white information.
6 color traps
When this item is selected, the color objects of the primary colors are trapped on a version-by-version basis. If you choose to compensate using the normal color transitions as usual, you should turn off this trapping feature. If you want to make good use of color, in addition to considering the role of primary color transitions, you should also consider black and vector-based trapping, automatic trapping settings to suit any other specification type of text.
However, automatic trapping is not suitable for the following situations:
A. Small font
People often put small fonts on a colored background and turn the background black to make it easier to read. But if you must put a spot color 24 point font on another spot color background, then reading is very difficult. If you need a colorful font, you should put it on a white background.
B. Fine line
Trap often distort the details.
2. Color to color trapping
In this way, trap relationships between two or more colors can be specified in advance in the Trap Specifications dialog box in the Define Color window. However, this trapping method is at least used by designers. Designers often use automatic trapping tools in combination with color design. There are usually 3 following situations:
1 Change the automatic trapping relationship between the two colors, which is specifically established for the printer.
2 When you set a color as the target for automatic trapping, enlarge the automatic trapping value for another color.
3 Create a color trap for auto-candling.
3. Change trapping regulations
Before resetting the trapping for each color, the color must be defined first. Of course, if the trapping is based on printing the original color, there is no need to set it.
Define and set the steps as follows:
Figure 15 Enter Trap Type Table
1) In the Define Colors dialog box, select the color you want to edit.
2) Edit the traps according to the diagram (see Figure 15).
3) Select the second color involved in the new trapping relationship (see Figure 15). Other colors in the file below this color are also listed in the dialog box. Selecting or changing this setting means that whenever a first color is overprinted on a second color, a new trap will be used. value.
4) Trap the dots so that the first color is overprinted on the second color, enter a value, such as 0.5, 2.5, or 4 points. Click the Trap button to set a new trap width, enter A value of 0 will cause this color to be completely hollowed out or not trapped at all.
5) Save.
6) Repeat this process to retain this color.
4. Trapping of objects to objects
Trapping object-to-object refers to editing trap information from one object to another. You must do this on the Trap Info panel that is floating under the View menu. By selecting objects and menus on the Trap Info panel, any objects created in QuarkXPress can be reset. On the Trap Info floating panel (see Figure 16), there are 6 options:
Figure 16 trapping information
1 The default value. That is, nothing has changed in the Trap Info panel. If the object accepts the value of Auto Amount, then Auto Amount will be displayed in the Trap Info panel. If all changes in the Trap Specification dialog box are displayed on this panel, the number will be displayed (see Figure 17).
Figure 17 Selecting Colors and Changing Trapping Parameters
2 overprint. Use this setting to overprint the color of the selected object on a background color. One advantage of choosing this option is that if you insist on printing small colored text on a background of different colors in a two-color job, there will be a slight offset in the color when overprinted, but it will still be acceptable. Fonts trapped or knocked out do not achieve this effect.
3 hollowing out. Hollow out selected objects, or accept overprinting, trapping information.
4 Quantitative (+). In the Trapping selection dialog, define the width of the selected object. Because the value is positive, the color of the object can be extended to the background.
5 Quantitative (-). Also in the Trapping selection dialog, the width of the selected object is defined, but a negative value means that the color of the object is indented and the background color is expanded.
6 optional. At this time, you are allowed to enter a custom trap width for the object in the file, both positive and negative.
If you select multiple objects or no objects are selected, you cannot change any settings because this tool only works on one object.
(b) Trapping in PageMaker
PageMaker's trapping information is controlled by the Trapping Preference dialog box, which can be found in the File menu (see Figure 18). Contrary to the QuarkXPress tool, the trap value that security can define is only a range, but the final trap depends on it. It cannot set a new trapping value in the color definition box, nor can it edit objects one by one and add new settings.
One of PageMaker's strengths is that it can turn trapping on or off. To prevent PageMaker from trapping at will, be careful not to click the Enable Trapping fo Publication button in the Trapping Preferences dialog box.
1. Trapping width
The trap width has the following two settings:
1 The default trap width. It can set any color other than black on the ground.
2 black trap width. It refers to the width of trapping the black or the underlying color of the field. This width is generally set to 1.5-2 times the default trap width.
2. Trapping threshold
Some jobs only need to be trapped when the color with great contrast changes, while for other jobs, trapping is required even if the lightest color change occurs. The StepLimit value determines the point where PageMaker traps. Increasing or decreasing this value can change the amount of ink used by PageMaker prior to trapping. The lower the percentage, the more PageMaker must be done between colors. More printed.
3. Centerline Trapping
Centerline trapping is often used when the same ink that is used in two adjacent colors reaches the maximum, in which case if the colors have the same density, no color defines the edges. For these traps, PageMaker determines the position of the trap by adjusting the brighter to darker outer spreads, so it can cross the centerline between them. We can set it anywhere within the 0-100% threshold range. At 0, all the traps set the centerline; at 100%, the centerline traps are avoided, resulting in full external expansion or retraction. Print workers should be consulted on this issue. Trap Text Above determines the minimum font to use for trapping in PageMaker.
Figure 18 PageMaker trapping options
4. Black attribute
The black limit setting determines what PageMaker thinks is black or ultra-black. When PageMaker encounters a color, PageMaker will apply the Black Width Trap value as long as the percentage of its black component is the same as or higher than the Black Minimum value, and it gives a field black in all blacks and super blacks in the field.