Photoshop Brushes, Softness, Opacity, and Flow

Part of Photoshop Tutorials

In photoshop, there are literally thousands of different configurations you can give a brush in the brushes pallette. But regardless of how you configure the brush, the four most important brush controls are size, softness, opacity and flow.

Size refers to how big the brush is; that's pretty simple. You can increase and decrease the size of a brush with the keyboard shortcuts [ and ].

Softness refers to how hard or soft the edges of the brush are. This is basically the same idea as feathering a selection, or running a Gaussian blur on an image. If you're painting on a layer mask, you'd want the brush to be a little bit softened to blend the edges. The softness can be changed with the keyboard shortcuts shift-[ and shift-].

Opacity and flow were always something that always confused me, but once I spent some time playing with them, it all made sense.

Changing the opacity of a brush controls how much "paint" it lays down in a single stroke. For example, with an opacity of 10%, a pure black brush will lay down 10% grey. As long as you hold down the mouse button, the tone you paint will not change, regardless of how often you stroke over it.

If you release the mouse button, then hold it down and paint again, it will add to any previous "paint" on the canvas. So, painting on an empty white canvas will give you 10% grey, as above. Painting over a previous 10% grey stroke will give you a 20% grey wherever the two strokes meet.

To change the opacity of a brush, hold down the shift key and type a number. For example, shift-5 will set the brush to 50% opacity, and shift-0 will set it to 100% opacity. For more control, type two numbers quickly; for example, shift-23 will set the brush to 23% opacity.

Now flow controls how rapidly paint "flows" out of the brush. Say you have a brush set to 10% flow. If you hold the mouse button down and don't move the mouse, the dot you're painting will darken from 10% to 20% all the way to 100% black. If you're moving the mouse, the "paint" will be darker where you moved the mouse slowly, and lighter where you moved it quickly.

Another way to think of flow is how rapidly the brush drops an image of itself. At 10% flow with a moving brush, the brush is "painted" 10% of the time, which leads to a line of overlapping circles. As the flow increases, the circles overlap more until finally, at 100%, it's a solid stroke.

I hope this explanation is helpful.

Comments

Mr Chris unverified user 5 Dec 2006	This was extremely helpful. I'm still learning color theory, and subsequently will have to tinker with how flow and opacity apply, but it is clear to me now, how the artists whose work I admire were able to achieve such subtly in their effects. Thank you for the time spent sharing this Darren.

Herman unverified user 15 Aug 2007	Thanks so much! This is EXACTLY what I needed to know. cheers!

DannyB unverified user 1 Nov 2007	simple, straightforward, and very useful, thank you!