Creating a vortex in Gimp

About a year ago, I did a tutorial on how to make eyes using Gimp. Here's my second Gimp tutorial, and this time I'm going to show how to create a vortex.

Start by creating a new image sized 1000x1000, and fill the background layer with solid black. Create a new layer and name it "Vortex Base".

Next, go to Filters->Render->Clouds->Plasma, and set "Turbulence" to 3. This will create a colorful plasma, turn this into black and white using Colors->Desaturate, with the default settings.

You now have a black and white plasma effect, we're gonna apply a motion blur effect to this. Go to Filters->Blur->Motion Blur. For "Blur Type", select "Zoom", set "Blur Center" to the center of your image (500-500 in this case), and "Length" to 100.

Finally, I adjusted brightness and contrast a bit. I set both brightness and contrast to 20. You want zoomed blur effect with plenty of contrast, but without large dark areas, so tweak the values a bit depending on your initial plasma effect.

From here on, we're not gonna touch the layer "Vortex Base" anymore, and work on copies of the layer instead. Create a copy of "Vortex Base" and rename it to "Vortex Whirl 1". Go to Filters->Distorts->Whirl and Pinch. Set "Whirl Angle" to 180, "Pinch Amount" to -1 and "Radius" to 2. This will create a hurricane-like vortex effect. Setting "Pinch Amount" to -1 makes all the difference here, it's this setting that creates the "eye" in the center.

Next, create another copy of "Vortex Base", rename it "Vortex Whirl 2" and put it on top of the layer stack. Apply the same whirl effect as on the first layer, only this time set "Whirl Angle" to 360. Hide the "Vortex Base" layer.

For the next step, you need the grid. Go to Image->Configure grid, set the grid size to 50 x 50 and the grid foreground color to orange. Enable the grid (View->Show Grid) and snapping (View->Snap to Grid).

Both vortex layers will get a layer mask. We're going to start with "Vortex Whirl 1", so hide "Vortex Whirl 2". Right click on the layer and select "Add Layer Mask". Initialize the mask to white (the default setting).

Now select the blend tool, set the shape to "Radial", the foreground color to white and the background color to black. With the blend tool, draw a radial gradient from the center (500-500) to coördinates 150-150 (this is where the grid comes in handy).

Repeat the same steps for "Vortex Whirl 2" and hide the grid again.

This still looks boring as hell, but the next step brings it to life. Set the layer mode of "Vortex Whirl 2" to "Divide", and the boring spiral turns into a glowing vortex.

This grayscale vortex will be the base for a colored, glowing vortex. The problem is, you can't merge the layers or the effect of the layer mode will be lost. How are we going to solve this? Go to the "Channels" tab, right click on one of the color channels (doesn't matter wich one) and select "Channel to Selection".

Go back to the layers tab, hide both "Vortex Whirl" layers and create a new layer titled "Vortex New". Set the foreground color to pure green and fill the layer. Keep the selection active for all the next steps!

The next step makes the vortex a lot denser. Create another new layer titled "Vortex Glow", set the foreground color to blue and fill the selection again. Set the layer mode to "Divide".

And finally, we're going to give the vortex a bright white glowing core. Create a new layer titled "Vortex Core" (keep the selection active!), set the foreground color to white and fill the selection. Ok, now you can go ahead and cancel the selection.

Add a layer mask to the "Vortex Core" layer (the same way you did with the "Vortex Whirl" layers), and with the blend tool, draw a radial gradient from the center out. In this example, I drew it from the center out about 3/4 horizontally to the left. This gives the vortex a bright, glowing core, but a dimmer outer edge.

As with my Eye tutorial, all these steps are open to experimentation. Blur effects, distortions, colors, layer modes, ... What I usually do when experimenting is wearing a headset and record everything I say, so if I stumble upon a cool effect, at least I can recall how I did it!

Posted in: Gimp