There is a technique to make a twirled abstract of an image using Photoshop. I wondered if I could get a similar effect using the GIMP. So I did some research. Nothing I could find did what I had in mind so I did some experimentation. This post is the process I arrived at.
I have found that the GIMP (Gnu Image Manipulation Program) is very powerful and can do pretty much anything Photoshop can do, but it is sometimes tricky to figure out where to find the commands and sometimes you have to add plug-ins. In the Photoshop tutorial linked to above they use a filter called “Mezzotint”. GIMP has a plug-in for that available, but I chose to see what I could do with the basic set of filters. In the end I was happy with the results I got using just two filters, Zoom Motion Blur and Whirl and Pinch. Getting a twirled effect using the GIMP was simpler than I had expected it to be.
Step 1: Load the photo in to the GIMP.
Step 2: Apply a radial blur
I duplicated the layer (to make my changes non-destructive. To apply the blur: Filters>Blur>Zoom Motion Blur. For this photo I moved the center and increased the blurring factor.
There are two ways to do this. You can use the sliders in the dialog box or the +’s on the photo. The white + is the center and the yellow + is the magnitude of the blur factor.
I experimented and wound up applying a blur factor of 0.515, bust repeated the action twice to get this result:
Step 3: Put a positive spin on it
Again I made a duplicate layer. So that I could go back and experiment with different possibilities. On this new layer I used Filters>Distorts>Whirl and Pinch.
For the technique you want this layer to have a positive value for whirl. I used the default of 90 (units are degrees of rotation).
Step 4: Put a negative spin on it
Make a duplicate of the layer from Step 2. Again for this layer you apply Filters>DIstorts>Whirl and Pinch, but this time use a negative value for whirl. In this case I used -150 (the units for this are degrees of rotation).
Step 5: Time to jive!
Now for some fun (as if spinning isn’t). This step is to merge the layers with positive and negative spin. The only way to figure out what works is to play around a bit. I moved the negatively spun layer (from Step 4) above the positively spun layer (from Step 3). Then experimented by changing the blend mode of the negative layer.
By using different blend modes you can create different twirled effects using the GIMP.
Addition mode 
Darken only mode 
Lighten only mode
Twirled Effect Using the GIMP
- Load the photo into the GIMP.
- Filters>Blur>Zoom Motion Blur, experiment to get an abstract of lines radiating. You can apply the filter multiple times.
- Create two copies of that layer.
- Apply a positive spin to one layer: Filters>Distorts>Whirl and Pinch. Make sure the whirl slider has a positive value.
- Apply a negative spin to the second layer: Filters>Distorts>Whirl and Pinch. give the whirl slider a negative value.
- Experiment with the layer blend modes to combine the two layers and find the one(s) you find most pleasing. You can save effects you like by using Layer>New from Visible. then make that layer invisible (click on the little eye beside the layer and it will turn off) to continue experimenting.
There are a few more posts with step-by-step instructions for doing things with the GIMP on my Nuts & Bolts & Tools page.