In a Spread, the object on top is “knocked out” of the one below it, creating a gap in the design, and the top color is extended to cover the bottom color. In a Choke, the top object is “knocked out” of the one below it, and the background color is brought into the knocked-out area to ensure proper trapping. In other words, a Spread is “a lighter object that overlaps a darker background and seems to expand into the background.” A Choke is “a lighter background that overlaps a darker object that falls within the background and seems to squeeze or reduce the object,” to prevent misregistration (Adobe).

Stroke

• In your Illustrator file, go to your sixth art board and using the type tool, create two “A”s and convert them into outlines (shift + command + o)
• Give the other “A” a fill of 100% cyan and a 50% cyan stroke
• With that “A” selected, go to the Object menu, select Path, and click Outline Stroke
• Go to the Window menu, select Pathfinder, and click Unite
• Give it a 1 pt. 100% black stroke and turn it into a 6 pt. dashed line in the stroke panel
• Select the first “A” and outline the stroke
• Use the shape builder tool and remove the stroke, and overlay it over the second “A”
• Make an arrow using the stroke panel and hold option and click to copy them
• Position the arrows around the edges of the “A” pointing out to demonstrate the color expanding from the inside

Choke

• Create another “A,” then using the rectangle tool, make a rectangle, fill it with 100% magenta, and place it behind one of the “A”s
• Apply a 50% magenta stroke to the “A”
• Outline the stroke
• Using the shape builder tool, hold option and click on the fill to knock it out the fill of the “A”
• Copy the “A” and give it a 1pt. black stroke
• Make it 6pt. dashed using the stroke panel
• Overlay the “A” inside the knocked out “A” in the box
• Repeat the process with the arrows as before, except place them so they are pointing inwards

Come back later for part 7, Knockout V.S. Overprint!