In another article, I showed you how to add a star diffraction effect to your images using some Photopea actions.

The problem with that approach is that it works only for certain sized stars and so can be difficult to get working in an image having stars of various sizes.

This article walks you through using another method, a custom brush for Photopea, for more flexibility.

The Result

The following is an image of Hickson Compact Group 30 with the star diffraction effect applied to various sized stars:

All of the stars were selected manually as was the size of the diffraction effect.

The method uses a custom brush in Photopea (you can use the brush in Photoshop and GIMP as well) – I explain how to acquire and install the custom brush in the next section.

Custom Brush Download and Installation

Use the following steps to download and install the custom brush in Photopea:

1. Download this file: RemoteAstrophotography-com-StarDiffractionBrush.zip

2. Unzip the file and store the contents somewhere convenient

3. Navigate to Photopea.com

4. Select File – Open

5. Locate and open the file that was included in this ZIP archive (StarDiffraction.abr)

Using The Custom Brush

1. Open an image using Photopea.

If you’re using the sample image of HCG 30, once you open the image, disable the letter layers and then select Layer –  Flatten Image to make selections easier for now.

2. Add a new Layer using the Layers panel as shown

3. Activate the new brush by doing the following:

a. Select the Brush tool on the left side of the screen (8th icon from the top, or press B on your keyboard)

b. Using the second icon from the top-left, click it to reval the set of brushes

c. Scroll down and locate the last brush called ‘LargeStarDiffraction’

d. Set the size to about 100

3. Find a medium-size star and sample its color to ensure the diffraction effect has the correct color:

a. Press the letter i on your keyboard (this activates the eyedropper tool)

b. Click the center of the star to sample the color and set the brush color

c. Press B to activate the Brush tool again

4. Click on the star to apply the diffraction effect

If you find the effect is too big, from the menu select Edit – Undo or press CTRL-z on your keyboard, change the size of the brush, and try again.

5. Apply the effect to some other stars in the image

6. Change the layer’s opacity to about 35%. Locate the Layer opacity slider and change it to about 35% to blend in the effects:

Save your image as PSD to maintain the layers or export as a PNG if you wish to share the image.

Note Regarding Updates

I have written another article that presents a more reliable method of creating diffraction spikes – access the article here: Creating Star Spikes: Reliable Method.

Conclusion

In this article, you learned of an alternate way of adding star diffraction spikes to your images using a custom brush tool for Photopea. You can use this custom brush in Photoshop as well as GIMP.