Create beautiful motion blur
Master Photoshop’s Radial Blur filter and learn how to get the long-exposure look – without the need for an ND filter!
Photoshop’s Radial Blur command is one of several filters that let you blur the detail in your photos. What’s clever about this particular filter is the direction in which it blurs. As the name suggests, it lets you blur in a radial way – either in concentric circles or bursting outwards from a centre point. The latter option can be used to mimic the look of clouds in motion, as if they have moved across the sky during a long exposure.
Of course, nothing beats capturing a real long exposure in-camera. But sometimes it may not be possible to do this. Perhaps you’ve been caught short without a tripod or ND filter, or maybe you’d like to try the effect out on one of the older landscape photos from your image library. Either way, you can mimic the look of motion blur in Photoshop with a combination of filter, selection and masking skills.
The kind of blur created by the Radial Blur filter has lots of other uses too, whether you want to add motion blur to car wheels or create a zoom burst effect.
Blur Method The filter offers two different types of blur. Spin works in a circular motion around the centre point, while zoom pushes the blur outwards from the centre point, like a zoom burst. Spin is useful for adding blur to wheels, for example, so that vehicles appear to be moving fast. Zoom is not only useful for blurring clouds like this, but also for creating all manner of vortex-like effects – try using it on the background in an action portrait for a dynamic blurred backdrop.
2 Selective blur The Radial Blur filter is most useful when you apply it selectively to parts of your photo, like the sky here. First need to make a duplicate layer (Ctrl/ Cmd+J), then select the area. The Quick Selection tool is ideal for selecting skies: simply paint over the area and Alt-paint to subtract if it goes wrong. Once done, add a Layer Mask to isolate the sky. Select and mask the sky before you convert your duplicate layer to a Smart Object, so that the blur doesn’t affect the bridge edges.
3 Smart Object By right-clicking a layer in Photoshop and selecting Convert To Smart Object, you can place it in a protective bubble, so that any changes you make to it remain non-destructive. You’re free to resize up or down, add tonal changes like Levels or Curves, or apply filters to the layer while still keeping everything editable. Any filters that are applied will appear as Smart Filters below the layer name. Simply double-click a Smart Filter to re-enter and experiment with settings later.
4 Quality There are three quality settings to choose from. Draft can leave unsightly noise and break up pixels, but it processes much quicker than Best. It makes sense to experiment with different blur amounts and blur centres while in Draft mode (ideally using a Smart Filter so you can change settings); once you’ve settled upon the direction and strength of blur, you can set the quality to Best to complete the effect.
5 Blur Center The Blur Center box lets you set a centre point for the radial blur. Drag around the box to set the centre. It’s not always obvious where to position the centre point, especially as it’s a square box and most images are rectangular, so it may take a little experimentation to get the result you want. If you need to reset the centre point to its default, hold Alt and click the Cancel/Reset button. (This works for all dialog boxes in Photoshop.)
6 A mount As the name suggests, this slider lets you control the strength of the blur effect. The higher the value, the further the blur stretches out. As with the other settings in the Radial Blur dialog, you usually need to experiment to come up with the right amount for your image. A fairly low setting of 18 lets you gently blur the clouds here. It simplifies the detail in the clouds, suggesting a long exposure.
James Paterson With a decade as a writer and photographer behind him, James knows exactly which Photoshop and Lightroom tools and techniques matter most.