My Favorite Use for Custom Strokes You have no idea how excited I am to see custom strokes in InDesign. This was one of the features I have wanted in the program since it first was released. Fortunately, they were introduced in InDesign CS. Here is a little lesson that explains my favorite way to use custom strokes and shows why this seemingly small feature is so important. Look at the illustration in figure  . Notice how the callout lines indicating the eye and button get lost as they move over the dark areas of the image. That's a real problem for people who do lots of book illustrations.
Notice how the black callout rules get lost as they pass over the dark areas of the image.  In the old days of pasteboard mechanicals we used to have special striped rules that were black with a white line on either side. What I need today is a way to create that look electronically. One of the ways I fixed this before InDesign CS was to create two rules. I started with a half-point black rule. I then copied the black rule, pasted the copy behind it, and set the copy to 1-point with a white stroke. This gave me a half-point rule with a quarter-point white stroke on either side. The white stroke became the knockout that helped keep the black from getting lost. Unfortunately, the technique was cumbersome and very awkward to work with if I had to move objects. Eventually it became so difficult to work with the multiple rules that I gave up altogether. Now look at the illustration in figure  . See how much easier it is to follow the callout across the image. That's because there's a special custom stroke applied to the rules.
Notice how a white line on either side of the black rule makes it easier to follow the rule as it passes over the dark areas of the image.  Here's how I created it. I made a custom stroke style which consists of two 25% stripes on either side of a 50% gap as seen in figure  . I saved this custom stroke.
Two stripes that take up 25% of the stroke width leave a 50% gap.  I drew the callout rules in the layout and applied the custom stroke from the Type menu in the Stroke palette  .
The custom stripe appears in the Type menu in the Stroke palette.  I set the stroke color as white  . Since the two stripes are set for 25% of the stroke width, I set the stroke weight to 1 point  . That made each side of the white knockout a quarter of a point.
A white stroke color was applied to the white stripes of the custom stroke. 
A 1-point stroke weight becomes a half-point gap color for the custom stroke.  I then needed to set the gap color in the Stroke palette to black  . Since the gap had been set for 50% of the stroke width, that made the black gap a half-point width.
When the Gap Color is set to black, the custom stripe shows a black line with two white stripes.  The benefits of this custom stroke are great. I only need to draw one object to apply two colors. And I can use this custom stroke for straight line rules as well as curves, rectangles, or any object that has to pass over multiple colors. In case you're wondering, I could have also defined the stroke as a single 50% stripe with two 25% gaps on top and bottom. In that case I would have used a black stroke with a white gap. Look carefully at the callout lines in this book. They have been set using a 1-point rule set with a single 50% black stripe with two 25% paper gaps around it. This rule was saved as my "Knockout Rule." | 
. The Stroke Styles dialog box appears 
.
.
:
.
.
.
.
.
. (
.
.
.
.
.
. Also, the Edit Stroke Style dialog box does not have an Add button.
.
