The streams of bubbles in the picture were drawn with a custom
bubble brush. I chose this approach rather than painting each bubble
separately as I wanted to keep a fast workflow rather than spend
a lot of time working on a quite minor background element.
My first step was the creation of the bubble graphic.
- Create a new canvas, 500 x 500 pixels with the background set
- Using the shape tool, create a black circle in the center of
the canvas (Fig 9).
- Rasterize the Layer and open the Layer Style palette
- Click on the Custom Blending box and set Fill Opacity to 0%.
What this does is make the circle invisible while leaving the
layer effects visible.
- Click on the Inner Shadow Box. The inner shadow will be used
to model the spherical form of the bubble. Set the shadow opacity
to 100% to get a good solid black. Set the distance to 0 so that
the shadow is applied evenly around the edge of the circle. Set
the size of the shadow to 100 or thereabouts. You can set the
Choke to about 25% to get a harder edge to the bubble. You should
now have something that looks like Fig 10.
This is our basic bubble. All it needs now is a bright highlight
to show the direction of the light source. Using your shape tool
again, make a small black circle and position it where you want
your highlight to be (Fig 11).
This is our complete bubble graphic. To turn it into a custom
brush, Open the edit menu and select ‘Define Brush'. Name the brush ‘Bubbles'
and hit OK.
Now, to adjust your brush. Hit B to select the brush tool. Your ‘Bubbles'
brush will have been added to the bottom of the list in the Brush
Preset Picker menu. Select it and make a stroke (Fig 12).
Select it and open the Brushes Palette. First of all we want to
have a stream of bubbles. To get a stream, under Brush Tip Shape,
set the spacing to 100%. This setting determines how often the
brush shape will repeat.
If you make a stroke with the brush now, you will get a stream
of evenly spaced and evenly sized bubbles (Fig 13). The next step
is to introduce some size variation.
Click on Shape dynamics and set the ‘Size Jitter' slider to zero
and the control to ‘Pen Pressure. Now make a stroke with your brush,
pressing lightly with your stylus at the beginning of the stroke
and increasing the pressure as you make the stroke. You should
end up with something like this (Fig 14).
That's more like it, but it's a little too regular. The answer
is to scatter the bubbles. Scattering moves the bubbles away from
the center of the stroke, while still following the general path
of the stroke. Set the brush scattering to 300% and you should
get something like this (Fig 15).
Once I had built my bubble brush, I laid down a couple of streams
of bubbles using white with the brush flow set to 50%.