First of all, let me start by saying I am not a professional graphics editor or such, so this how-to might be total nonsense to a pro. But it works for my goals.

That being stated, let me show you how to create a fancy background using GIMP and some simple techniques.

1. Let’s start with an empty image. Since we’re going to have a filled background, I usually start with a white layer

File > New… > 800×400 (or whatever size you need)

2. Now we can start and fill the layer using the blend tool.

Tools > Drawing > Blend

Set the mode to “Difference“, choose a multicolored gradient (anyone you like, as long as it has more than 2 colors; I’m going to use the “Shadow 3” preset in this example), set any form you like (linear, radial or else) and start filling freely, changing directions each time. This is what I get after drawing about 10-15 gradient lines.

using only linear gradients

using just radial gradients

When you’re happy with the result, you can jump to the next step.

3. Turn everything to black and white using the Desaturate tool.

Colors > Desaturate

Choose the options that give you the result you prefer (I have been using the Lightness option)

desaturated image

4. Now you can apply a last finishing touch using the blend tool again. This time change the mode to “Soft light” and use a gradient with a combination of soft colors.

Check the examples below.

example 1

example 2

example 3

example 4