How to Change Color Borders in Illustratorby Payton Pritchard ; Updated September 28, 2017
Adobe Illustrator offers a variety of border options. Various patterns offer unique styles, and fills and strokes can be applied to make them more interesting.
Go to "File" > "Place" to place your image on the artboard. Select the "Rectangle" tool and draw it around the image on the artboard. Shapes can be given a color fill or color stroke. Choose a decorative border from the "Brushes" panel. If it's not open, go to "Window" > "Brushes" to open the panel. All panels can be opened or closed from the "Window" menu.
Click on the down arrow to the far right of the "Brushes" panel to display the submenu. Scroll to the bottom and move the mouse over the submenu "Open Brush Library" > "Decorative." Click on the decorative brushes of your choice, such as "Elegant Curl_Floral Brush Set," to open the panel featuring a selection of decorative brushes for borders.
Experiment with decorative brushes until you find one you like. Specify the weight of the decorative brush from the "Options" bar.
Change the color of the decorative brushes using a solid color on the stroke, not the fill. Remember, the border is the stroke of a rectangle created around the image. Choosing to fill the rectangle with color will cover the image.
Borders with Fill & Stroke
Select the border and go to "Object" > "Expand Appearance." You'll notice additional paths and anchor points appear along the border. Your border is now an expanded object that a fill and stroke can be applied to.
Select "Fill" from the "Tools" panel and fill the border with a solid color without a stroke. Click on the square with the red line through it to turn off a fill or stroke. This means no stroke or fill when selected. You'll notice the border appears the same as it did with a stroke before the border was expanded.
Go to "Window" > "Gradient" with "Fill" still selected. A gradient can only be applied to a brush that has been expanded because it's an object with paths and anchor points. Change gradient colors by double clicking on the sliders. You now have a gradient color on the border.
Select the stroke from the "Tools" panel and remove the fill. The stroke on an expanded border now appears as an outline with no color inside the decorative brush.