Making (Digital) Buttery Acrylic Brushes

"Louisbourg Light"

The “Acrylic” brushes in Rebelle may make rather thin and scruffy marks off the shelf, but if you prefer thick paint marks that are buttery smooth, I’ve got some new brushes for you right here! You can see the lovely marks they can make in “Louisbourg Light” above.

Free Download: Two Buttery Acrylic Brushes

Here are two of my buttery brushes—the Flat Butter and the Rigger Butter—that I prefer to the Rebelle original Acrylic brushes. I encourage you to try these brushes and adjust them to fit your painting style. It's easy to add brushes to Rebelle: just copy the two images below to your computer, and then drag and drop them into the Acrylic brush section of Rebelle (or, use the Import Brush Preset command in the Acrylic brush section).

Flat Butter Acrylic Brush

Rigger Butter Acrylic Brush

Several of the parameters chosen in Rebelle Brush Creator help these brushes produce such smooth marks—like a flat brush or rigger brush, respectively, loaded with gooey acrylic or oil paint. Continue reading to see how those parameters work and how you might modify them for special uses.

Understanding the Flat Butter Acrylic Brush

The Flat Butter Acrylic brush has these parameters in Rebelle Brush Creator:

So, why these parameters?

1. One aspect of this brush’s smooth mark is its even grain. In Rebelle, the Shape and Grain act like two masks, one above the other, that combine to direct the color into a basic stamp "shape." I chose “Flat Noisy 2” for the Shape and “_01-3 blurred lighter” for the Grain. Note, you might make this basic shape rougher by substituting a noisier Grain with more distinct white and black areas—e.g., using “Sponge 2” for a bit rougher mark or something like "Splats" or “Splats-02” for a much rougher mark. Or, you could design your own Grain in photo software! 
2. This brush emulates a traditional, rather stiff, synthetic brush: it can be brushed lightly across the canvas and the bristles will bend and splay just a little under pressure. To capture this behavior, I lowered the Pressure Size to 20 and Pressure Opacity to 100. (If these settings were 0, then increasing pressure on the digital pen would have no effect on the size or opacity of the mark.) These positive settings mean the mark gets a bit larger (but not too much larger, since the bristles are short) and much more opaque as you press harder with the digital pen. The flip side of the latter feature means when you lightly touch the digital pen to the tablet or screen, the mark is more transparent. 
3. Another aspect of the smooth “buttery” mark is the close Spacing of the shape. I pulled this down to 5 and left the Scatter at 0 (for comparison, the Rebelle Flat Acrylic brush is set at 10 and 0, respectively). The Spacing determines how far apart that basic stamp shape is placed in the line of your stroke, and the Scatter determines how its placement varies from side to side of the line of your stroke. This brush has a very even stamp shape, and it enhances this by placing those shapes close together. Then, to further smooth things out, I turned on Smudge. If the brush stroke lags on your computer, you can turn off Smudge to speed up the mark.
4. Artists paint with traditional flat brushes on both the flat side and the edge of the bristles, but a digital brush can’t emulate that versatility. Currently this brush is set up to paint on the flat side: I set Shape Rotation to "Pen Rotation," which will 'rotate' the basic shape to keep its wide edge perpendicular to the direction of your pen stroke.
5. Traditional flat brushes vary in width from 1/4 inch (size 2) to 1 inch (size 24). This digital brush can mimic that range on a 200-dpi canvas: it makes a 1/4-inch wide mark when set at size 50 and a one-inch wide mark when set at the largest size, which is 100. On a 300-dpi canvas, the widest mark will be 3/4 inch. (The maximum width of the mark is a function of the Rebelle Acrylic category and cannot be increased by adjusting the individual brush's parameters.)
6. A low setting of 10 for Canvas Texture keeps the brush mark smooth on every sort of canvas. Note, you could increase Texture to around 60 or 70 to create a brush that gives a rough mark on heavily textured canvas.

Understanding the Rigger Butter Acrylic Brush

The Rigger Butter is like the Flat Butter brush in many ways. The main differences are the shape (“Small Round” instead of “Flat Noisy 2”) and how the Rigger Butter brush responds to pressure. The Pressure Size parameter of 100 means the brush makes a narrow mark under a light touch, but a wider mark with more pressure. This emulates the long, soft hairs of a traditional rigger brush. The Pressure Opacity parameter of -10 means there is almost no change in the opacity of the mark as you press harder with the digital pen.

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Thanks for reading!

I hope that you enjoyed this post and that it inspires you to enjoy digital painting. If you find this post helpful, please share it with your friends. And please send me your insights on digital painting and suggestions for Digital Paint Spot.

Bob Kruschwitz