GIMP Fractal Backgrounds
From Gentoo Linux Wiki
Contents |
[edit] Introduction
This short how-to describes how to make a simple and yet visually appealing background for your computer in very little time with very little skill.
[edit] Prerequisites
To create these images, you will need GIMP, an open source image editor available for most operating systems including Windows, BSD, and other OS distros. To get GIMP you can do:
Otherwise, you can always go to the GIMP homepage. An installer exists in the downloads section for Microsoft Windows users.
[edit] Step 1: Make Image
This is the very simple method to follow:
- Open GIMP.
- Set Foreground colour to Black (it should be black by default)
- In menu, select File --> New
- In Create a New Image, select the desired resolution.
- Also set Advanced --> Fill With to "Foreground Colour"
- Optional: Click on greyscale bar and set the gradient to something else. This can produce mixed results.
- Press OK
- On the Menu for the image, select Filters --> Render --> Nature --> Flame
[edit] Step 2: Setting up Flame
The images shown used this method; however, not all the images in the collection were done with this method. This method will take longer to process. On an Athlon64 3000+ the flame render takes about a minute or two.
Starting in the flame dialog:
- Go to tab Camera and set Zoom to "3"
- Optional: Use "1.5" for higher speed.
- Click Edit
- In the "Edit Flame" dialog, set Variation to "Spherical".
- Optional: Sinusoidal also works well at a high zoom.
- Now you must look at the nine boxes. If you like a pattern, choose it. If not, click Randomize. Note, this may be slow.
- When a suitable flame pattern has been chosen click OK.
- In the dialog "Flame" goto the Camera tab and adjust X and Y until you get an image that is fairly centered or otherwise looks good.
- Click OK. Wait a while. This step takes a while!
[edit] Step 3: Colour Time
Now your image probably looks somewhat like the image on the right.
The next step is to add colour. You have to decide what colour to use. Blue pretty much always works well, and Red rarely works very well as variations in red end up looking purple or yellow. Orange is another good choice. Green is not too hard to get working either.
[edit] Channel Mixer Method
- In the menu for the image, choose Colours --> Components --> Channel Mixer - in older version of gimp it's in Filters.
- Now, set Output Channel to the colour you want to dominate in the image.
- Changing Red, Green, or Blue will make parts of the image that are those colour become more or less of the Output Channel Colour.
- Adjust the settings here until a desired look is obtained.
- Click OK
- In the GIMP Menu, Choose File --> Save As
[edit] Alternate: Colourize
This one is a bit easier to get the desired results:
- In the menu for the image, choose Colours --> Colourize
- Either choose one of the preset colours or make your own custom colour
- Click OK to apply the settings
- In the GIMP Menu, Choose File --> Save As
[edit] Alternate: Blend Multiple Layers
With this you may pick the exact colour you want to use and even modify it dramatically later.
- Create a new layer.
- From your toolbox, pick your desired colour as the foreground colour.
- Select your created layer and choose Edit --> Fill with FG Colour.
- Now, from your layers box at the top, find the Mode drop down and select Multiply.
- Play around with different layers, blending modes, opacities, and colour adjustments to achieve the desired effect.
[edit] Alternate: Flame Gradient
- Before running Flame, set your FG and BG colours to the colours of your choice. Make them similar, though (for example, red and orange, etc.) Set your gradient to "FG to BG (RGB)". This will cause Flame to use your gradient as the colouring scheme, which results in the flame being this colour. There is no need to do anything else.
[edit] Tips
- Avoid setting multiple values to 200. Generally this makes the image a bit flat and undetailed.
- Setting the Gradient creates images where some parts have more green and other more blue, or such. This allows for more flexibility in the Channel Mixer.
- Experiment with multiple flame renders before adding colour - this can create awesome effects!
- Setting a gradient from the main gimp dialog then choosing Custom Gradient from the colourmap box on the rendering tab(in the flame dialog) can create multi-coloured flames
- You can use layers and different flame renders on each layer to create an image with multiple colours
- Save as PNG, not JPG
- Make the image "indexed" rather than RGB, to save diskspace (and memory). Right click and select Image --> Mode --> Indexed. Just choose select optimum palette.
- Note that this may not work well if you selected the "Blend Multiple Layers" alternative above. For more complex images there is often too many colours if you blend in advanced ways.
- Using tools like optipng (from media-gfx/optipng) and advpng (from app-arch/advancecomp) is always a good generic way to reduce image size without affecting image quality. Use advpng -z1 image.png && optipng -i0 -o7 image.png && advpng -z4 image.png for the best result (since they compress in different ways). Replace image.png with the name of the image file of course.
- Try multiple Filter --> Colour effects. Like mapping to alien2 or (after colourizing with the channel mixer), Sample Colourize from a gradient.
- When using multiple flames on the same canvas, try using the same exact flame, just rotate or flip the entire image before putting the new flame on top. This will result in a more symmetrical / kaleidoscope type images.
- If using Gnome set the background colour to transparent, the background colour can then be controlled from the desktop control dialog
[edit] Issues
- Currently the GIMP flame plugin appears to have issues generating flames on large images. The page says the plug-in worked in a quick test for a 1024x768 pixel image, but didn't do it for a 2500x2500 pixel image. However a test showed that this issue seems to be fixed in 2.4.6 at least.
[edit] Gallery of examples
Here are some example images. Feel free to add your own.
(1024×768) |
(1024×768) |
 (1400x1050) |
(1400x1050) |
 (1250×1024) |
 (1440×900) |
 (1680x1050) |
