Use a captured brush to create billboard artwork

If you want to re-create Monica Amneus' brushes, open the Undersea brushes Library. Click Save to Creative Cloud to create a copy of the Library in your own account.

Once you have them saved to a Library, you can use these assets to create brushes with Capture. Then use your new custom brushes in Photoshop Sketch, Photoshop or Illustrator.

To create your own custom brush from Monica's sketch, open Capture, choose Brushes then tap +. Then tap the Capture From icon at the bottom-right of the screen.

Choose Creative Cloud from the menu. Tap Files, change it to Library Assets, and select the Undersea brushes library.

Tap Brush doodles, then tap Open. Tap on the white background color to remove it from your final brush. Dropping the background can help isolate a specific shape or stroke. When you're done, tap the green button.

Note: You can also create a brush from a captured image. See Capture colors, shapes, and brushes on the go for more.

Isolate a shape or stroke to use in your brush, by using pinch gestures to scale and rotate the captured image. 

Then position the crop controls around the portion of the image you want to make into a brush. Tap Next.

In the Adobe Photoshop Brushes section, you can choose from three different presets to get a great looking brush. Tap the second option. This will give you a repeating pattern brush stroke that follows the direction in which you're painting. Tap Next.

Draw a few strokes to test out the brush style. Tap Edit Brush to make further refinements.

Tap Presets and adjust the Size slider to set the point size of the brush. Decrease the Spacing to create a continuous stroke, and increase Flow jitter to add some irregularity to how much color is laid down as you paint. Try the other controls to create a unique look.

When you're finished, tap Done. Draw a few strokes to Preview your brush, then tap Next.

Finally, give your brush a name like Seaweed. Choose a library where you want to save the brush or leave it set to the default, My Library. Tap Save Brush.

Launch Photoshop and open a document. To access your brush, go to Window > CC Libraries, and then select the library where you saved your brush. Click the brush's thumbnail in the Libraries panel to select it.

Choose a color and try painting with your new custom brush.

Use the other images in Monica's library to create more custom brushes and finish your billboard.