Create Custom Bokeh Using Shape Blur Filter

Custom bokeh transforms standard out-of-focus light into artistic patterns such as hearts, stars, or diamonds, adding a stylized atmosphere to photography. This guide provides a straightforward method for using the shape blur filter in raster graphic software to isolate highlights, define custom vector shapes, and apply distinct blur silhouettes to your backgrounds.

Step 1: Prepare the Image

Open your image and duplicate the background layer to preserve the original. For the most convincing effect, choose an image with prominent background highlights or point light sources (such as city lights or fairy lights).

If your image includes a foreground subject:

  1. Use a selection tool to select your subject.
  2. Invert the selection so only the background is active, or separate the subject onto its own layer above the background.
  3. Content-aware fill the area behind the subject on the background layer to prevent edge artifacts when blurred.

Step 2: Choose or Define Your Custom Shape

The Shape Blur filter uses vector shapes to dictate how pixels disperse.

  1. Select your software’s Custom Shape tool.
  2. Browse the shape library to choose a preset, or draw a custom vector shape (e.g., a star, heart, or polygon) using the Pen tool.
  3. Save the custom shape so it is accessible within the filter's shape library.

Step 3: Boost Background Highlights

Bokeh shapes are most visible in bright areas. To emphasize them:

  1. Select the background layer.
  2. Add a Curves or Levels adjustment clipped directly to that layer.
  3. Increase the contrast by pulling down the midtones and boosting the highlights, making the light points stand out against darker elements.

Step 4: Apply the Shape Blur

  1. Convert the background layer into a Smart Object so the filter settings remain editable.
  2. Navigate to Filter > Blur > Shape Blur.
  3. In the dialog box, browse the shape palette and select the shape you loaded or created.
  4. Adjust the Radius slider. A higher radius creates larger, more visible bokeh shapes, while a lower radius keeps the shape compact and subtle.
  5. Click OK to apply.

Step 5: Blend and Refine

  1. If the blur looks flat, duplicate the blurred layer and set the blend mode to Screen or Linear Dodge (Add) at a lower opacity to give the bokeh a luminous glow.
  2. Add a layer mask to the blurred layer to paint away the effect in areas where you want a natural transition or less blur.
  3. Ensure the foreground subject layer sits on top of the blurred background with clean edges.