This probably isn’t really a Bokeh effect, but it will give you the tools to create one, if you take more time that I am going to take in this tutorial.
I’ve opened a new file 800 X 600@72 dpi with a white background (this can be changed later), and then created a new layer above that by using the ‘create new layer icon at the bottom of the layers palette’ or you can press Shift + Ctrl + N on the keyboard and click OK to accept the default name, or name it something different.
Before we go on the theory behind this effect is on each new layer, you are going to half the brush size and half the Gaussian Blur amount. That isn’t a hard and fast rule, it is just what you are going to be doing here. You are also going to be doing a Gradient Layer and you can change anything in the dialogue box that you want. I’m going to be using the default Gradients, probably without adjusting them. You can play to your hearts content with the different settings and hopefully come up with some really cool effects. I’m also going to be using a simple hard edged round brush, because none of us are likely to have the same brushes installed. Feel free to use other brushes.
So, on with the business. Select a hard edged round brush from the brushes palette, I have chosen a 175 pixel brush and you are going to go and make some adjustments to the settings in the brushes palette. You can access that by going to Window>Brushes, or using the little window thingy on the top left of the top menu bar. See image.
Click on Shape Dynamics and you can punch in the same numbers that I have.
Click on Scattering and punch in the same numbers.
Click on ‘Other Dynamics’ and punch in the same numbers.
And then you can close the dialogue box. Make sure that your f/ground is set to black and the b/ground to white, and working on the new blank layer you created earlier, just click a couple of times in a different place. See image.
Now go to the ‘Fill’ option at the top right of the layers palette and take it all the way down to 0% – the brush strokes will disappear. From the FX icon at the bottom of the Layers Palette, choose Gradient Overlay. The default gradient will appear (i.e. black & white) click on the downward facing arrow beside the black to white gradient to open the gradient picker. I’ve picked a default blue gradient and left all the other settings alone.
When you have everything as want it, click OK to accept the changes. Go to Filter>Blur>Gaussian Blur and choose a setting that you like, or you can punch in the numbers that I have below.
You can still add other effects to each of these layers – drop shadow, outer or inner glow etc., Now repeat the same process for as many layers as you like. The final layer would probably be free of the Gaussian Blur filter. In the image below I have used 5 layers. On a couple of the layers I changed the setting for the gradient to reflective and radial and inverted the gradient. On the last layer I used a fireworks brush and chose a different gradient, I also added a drop shadow and sharpened it. Finally, I unlocked the b/ground layer added a gradient. And the final image is below.