
I also duplicate brushes to create new pattern brushes and just change out the grain source. Once a brush is created, you can make variations by duplicating it.
Turn off all of the layers, make a new one, and test the brush out. (The opacity can be changed when using the brush.) Under apply pencil, change the opacity to none to create a solid pattern no matter the pressure of the Apple pencil. This gives the pattern a softer edge when coloring over another color. Under shape, change the source by clicking import, source library, and select soft. Change the scale if you want a different size. This keeps the pattern in the same place when you color over it. Click edit, import, and paste to add your pattern. Make sure that all of the layers are turned on and copy the canvas. You can turn off the drawing guides because you won't need them anymore. When you're happy with your pattern, it's time to turn it into a pattern brush. Make a new layer and fill in the center part. Turn off the drawing guide and zoom in to make sure that there are no gaps between the pattern blocks. Continue until all 4 layers are moved to corners. Turn on the next layer and move it to another corner. Select the top layer and move it to a corner. This helps perfectly align the pattern to the grid. Select a layer and make sure that snapping and magnetics are toggled on and increase distance and velocity to max. Duplicate the flattened layer 3 more times. Tap on the new group and select flatten. (Group by dragging both layers to the right.) Group the black background layer and the drawing layer. When you have the center area filled, it's time to make the pattern. When I make patterns, I stick to the center axis for this step. Make a new layer and draw with white to create your pattern. The grid size should be set to max, increase the opacity and line thickness, and choose a bright color that will contrast with the black and white. Make a new layer on top of that and fill it with black.
Create a new layer and fill it with a bright color.I usually make mine 2000 px by 2000 px, 300 DPI. Open a new canvas and make it a square size.Working in layers will allow you to use the same artwork and recolor it for other projects.You can use gray, but those parts will be transparent.Black will be #000000, and white will be #ffffff. The background should be black and the pattern should be white (though it is possible to invert it in the brush-making process.) Make sure it's solid black and solid white. I like to make mine at least 2000 px by 2000 px. A rectangle canvas will create a warped brush.
You have to start with a SQUARE canvas.
There's a few important things to know before getting started.
SEAMLESS PATTERN HOW TO
How to Make a Seamless Pattern Brush in Procreate