This guide will assume you’ve already got Gimp installed and running. If not, packages for Linux, Windows, and Mac can be found here.
Background
To begin with, we’ll need a background of the proper size. Choose File -> New and pick the options for the size of your image. The examples will be using a widescreen 1440×900 setup.
If you wish, you may also choose the Advanced Options and set the background fill to Foreground Color. This will fill it with black so that we do not have to use the bucket fill later.
If you do not want a black background, you can hit OK for now and then use the Bucket tool to pour in the background color of your choice.
Choosing Color Scheme
There are multiple ways to set the colors our our abstract effect, but the simplest is to choose them even before we create the image. In short, we’ll be creating a gimp flame that will be composed of the colors you choose as foreground and background colors.
If you know you want a very blue-ish end result, choose whatever blue shades you think are appropriate for the normal Foreground and Background colors. For the best results, choose one that’s somewhat dark, and another that’s somewhat light.
Creating the Flame
Now that we’ve got an image of appropriate size and background color, we can create our shapes and colors. In the Layers box, click the blank shet of paper to add a new layer. Name it “flame” and set the type to Transparency. Your layer window should now look something like this.
Next, choose Filters > Render > Nature > Flame.
The first thing you’ll want to do is move over to the Camera tab, and increase the Zoom level so that the flame occupies most of the preview screen. Don’t worry about getting it too exact, as we are about to create an entirely new custom flame.
In the top of that window, choose the Edit button, which will let us make out own custom flame.
Hitting Randomize will give you entirely different flame styles, some with smooth curves, some with jagged lines, and many in between. Hit Randomize until you find something that suits your style, then adjust the Speed setting to make finer adjustments. Pick whichever result suits you best, and click OK.
You’ll be taken back to the main flame settings, where you can make any other adjustments you see fit. These settings can be adjusted at will, however I would recommend increasing the Density option to give a better end result. This will, however, increase the rendering time significantly.
Once you click OK, it will likely take a while before Gimp can display the final fully rendered output.
Touchup
There are times that the rendered output doesn’t perfectly match the preview. If this happens, you can either redo the flame or adjust the color settings with any of the tools in the Colors menu to tweak brightness, saturation, and other settings.
Additionally, you can create multiple layers with multiple flames to give your image more depth and color. Gimp provides several rending tools to add other elements such as clouds and lighting effects to further increase the complexity of your image. As always with Gimp, just toy around and have fun. You can always hit “undo”.
