This GIMP (GNU) tutorial demonstrates how to create gradient background patterns using GIMPs Sinus Filter.
You can quickly Undo a step at any time by pressing Ctrl then Z. Alternatively, click a previous Undo History snapshot - Windows then Dockable Dialogues then click Undo History. In addition, to Zoom in (or Zoom out) of your image; from the top menu choose View then select a Zoom Tool from the subsequent drop-down list.
Launch GIMP & Organise Its Workspace & Palettes
Create a New (Transparent) Image, and set the following Width and Height dimensions; (File then New - Ctrl then N). Alternatively, select Height and Width dimensions of your choice.
Now, from the top menu, choose Filters then choose Render and then choose Pattern and then choose Sinus. And from the subsequent Sinus dialogue box, experiment with the settings, and then click OK.
For personal results, experiment with the Settings, Colours and Blend tabs.
After setting a Blend of your choice, click OK to apply your pattern
Congratulations, your Sinus Filter Pattern is complete, and it is ready to save, and to incorporate into your artwork - top menu, then File then Save As.
GIMP 2.8 - File then Export.
Sinus Filter Notes
The Sinus filter lets you make sinusoidally based textures, which look rather like watered silk or maybe plywood. This plugin works by using two different colours that you can define in the Colours tab. These two colours then create wave patterns based on a sine function.
This option controls the random behaviour of the filter. If the same random seed in the same situation is used, the filter produces exactly the same results. A different random seed produces different results. Random seed can be entered manually or generated randomly by pressing the New Seed button.
When the Randomise option is marked, random seed cannot be entered manually, but is randomly generated each time the filter is run. If it is not marked, the filter remembers the last random seed used.
If you mark this, you'll get a pattern that can be used for tiling. For example, you can use it as a background in an HTML page, and the tile edges will be joined seamlessly.
This options give additional control of the interaction between the two colours.
Here, you set the two colours that make up your texture. You can use Black & White or the Foreground & Background colours in the Toolbox, or you can Choose a colour with the colour icons.
This slider allows you to assign an opacity to each of the colours. (If the Layer you are working on does not have an Alpha Channel, they will be greyed out.)
You can choose between three functions to set the shapes of the waves that are produced: Linear, Bilinear and Sinusoidal.
The Exponent controls which of the two colours is dominant, and how dominant it
is. If you set the exponent to -7.5, the left colour will dominate totally, and if you set it to +7.5 it will be the other way around. A zero value is neutral.
Wendi E. M. Scarth. Top of Page.