Digital Darkroom

Add atmosphere to light sources in low-light and night scenes by creating your own customised starburst brushes – far more effective than using a camera filter

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SOFTWARE Photoshop CC GET IT FROM www.adobe.com Get Start files from The Resources folder on the disc

If you use a small aperture like f/11 or f/16 when you shoot a night scene, you’ll create glowing starburst effects that emanate from point light sources

in the frame. Traditionally, this effect is enhanced by using an optical ‘star’ filter over the lens. These come in various types, depending on how many streaks of light you want the light source to create, and they work by having the appropriate pattern etched into the surface of the filter.

The pattern causes the light to reflect and streak along the filter’s etched lines, but the results can look rather artificial, as the etched pattern is uniform. This means that starbursts from distant light sources will be scaled the same as those nearer the camera, which gives an unnatural appearance. Another downside is that the entire filter surface is broken up by the etching, so overall image degradation is unavoidable.

This Photoshop-based technique avoids the first problem, because it allows you to vary the scale and intensity of your starbursts. Also, it creates no degradation across the image, because you only add the starburst effects where you want them. This puts you in complete control of the overall look, and you can make the impact of your starbursts as subtle – or as loud – as you want.

The technique involves building a special custom brush, then simply applying it wherever you want, but this is much easier than you’d expect. The whole process is outlined here, and once you’ve made your brush, you can use it to create starbursts with just a few clicks whenever you like.

1 Create a new document

Go to File > New in Photoshop; under Preset Details on the right of the New Document palette, set the units to Pixels and type in 2000 for both Width and Height. Set the Resolution to 300 Pixels/Inch, and make sure that RGB Color and 8 Bit are selected under Color Mode. Choose the White option from the dropdown list under Background Contents and click OK to see a new square, white document on-screen.

2 Start building your starburst

Create a new layer by pressing Ctrl/Cmd+Alt+Shift+N, then press D to set the foreground colour to black. Select the Pencil tool – it’s grouped with the Brush tool, so if you can’t see it, click and hold on the Brush tool to get it. In the Options bar at the top of the screen, set the Pencil size to 10px by tapping the square brackets keys until 10 appears as the size. Check that Opacity is set to 100% and, while holding Shift, click in the middle of the square. Keep the mouse held down and drag to the left until you’re halfway to the edge. Still holding Shift, drag to the right, until you have a horizontal line in the middle of the screen that’s about 50% of the total width of the image.

3 Blur the edges and make a cross

Go to Filter > Blur > Motion Blur; in the dialog box, set Angle to 0 degrees and Distance to 500px. Click OK and your line will extend, gradually fading and feathering out at both ends. You need to copy this feathered line to a new layer, so press Ctrl/Cmd+J to see a duplicate layer appear in the Layers panel. Now press Ctrl/Cmd+T to go into Free Transform mode and, while holding Shift, drag the mouse outside the line to rotate it until it’s vertical. Press Return to set it down, then press Ctrl/Cmd+E to collapse the two layers into one, giving a black cross.

4 Add flare to the centre

Press Ctrl/Cmd+J once more to copy the cross onto a new layer, and press Ctrl/Cmd+T to bring up the Free Transform bounding box. While holding Shift, rotate this so it’s at 45 degrees to the cross, giving an 8-pointed star shape. Press Return to set it down, and once more, press Ctrl/Cmd+E to crunch the two layers into one. Press Ctrl/Cmd+Alt+Shift+N to make a new layer, then press Alt+Backspace to fill it with black. Go to Filter > Render > Lens Flare, and use a Brightness of 100% and a 50-300mm zoom. Drag the flare in the Preview so it’s centred, and click OK.

5 Complete your starburst effect

In the Layers panel, click where it says Normal and set the Blending Mode to Multiply, then press Ctrl/Cmd+I to invert the colours. Press V to select the Move tool, and drag the flare so it’s positioned right in the middle of your star shape. Press Ctrl/Cmd+Shift+U to remove the colour from the flare, then press Ctrl/Cmd+E to condense the flare and the star into a single layer. To soften the edges and make the starburst effect more realistic, go to Filter > Blur > Gaussian Blur. In the dialog box, enter a Radius of 3px and click OK.

6 Turn it into a custom brush

With your completed starburst effect on-screen, go to Edit > Define Brush Preset; in the dialog box that pops up, rename it to ‘Star 8’. Click OK, and the new custom brush will be added to your list of brushes. Click on the Brush Preset Picker, and you’ll see it at the bottom of your list of brushes. You can create a variety of different starburst effects using the same technique, adding four-, six- and 16-point stars with different-sized spokes and flares.

7 Add your first starburst

To use your new brush, open a night shot with some point light sources. If you don’t have one handy, use the provided start image Night Road.jpg for practice. Once it’s on-screen, create a new layer (Ctrl/ Cmd+Alt+Shift+N) and press D then X to set white as your foreground colour. With the Brush tool selected, pick your new Star 8 brush, and adjust its size using the square bracket keys. Position it directly over a light source and click once to apply the effect. For a more defined look, click again for a brighter ‘double hit’. Just take care not to move the mouse between clicks if you do this.

8 Complete your starburst effects

With the first starburst in place, now place additional starbursts over all the other point sources of light in the frame, adjusting the brush size as you go to suit the brightness of the light source and its distance from the camera. Use single hits for dimmer lights, and double hits for brighter ones. To ensure your positioning is accurate, zoom in on each light source (Ctrl/Cmd+Plus) to make sure your brush is bang on target. Once all your starburst effects are in place, go to Filter > Blur > Gaussian Blur and add a Radius of 3-5px to soften the effect and make it more realistic.

9 Add a hint of colour

You may find your starbursts look perfect in white, but if you want to add a little colour to them, click on the Adjustment Layer icon in the Layers panel, and select Hue/Saturation from the list. In the palette, click on the clip layer icon (the left-most option at the bottom of the palette). This will ensure that the colour changes will only affect the starbursts in the scene, not the entire image. Tick the Colorize box, then move Lightness to around -3. Now ramp up the Saturation to +100, then move the Hue slider to add the colour of your choice.