Back in the old days, when Ultra Fractal (UF) was nowhere to be found, all available fractal generators produced single-layer images, and most still do. Only UF introduced image manipulation options, such as layers and alpha channels, similar to those found in graphics editor packages. Since then, there’s been no need to leave the program to post-process a picture (unless you want to add text, apply special filters or combine extra graphical elements). These unique features are largely responsible for this generator’s increase in popularity among fractal enthusiasts.
Usually, we say a fractal image has been post-processed when it is imported into a graphics editor to adjust any of its original properties. This results in a modification of the master picture as it came out of the fractal-generating software. While this is a common practice in digital graphics creation, it still divides fractal artists into two camps: those who prefer to preserve the fractal in its natural form, and those who routinely enhance its appearance to improve or elevate the artistic output. UF helped shift that perception, as most fractal artists now use it almost exclusively, taking advantage on its ability to mix layers into a single image. Since all adjustments are done within the same application, those users believe they’re not post-processing the picture. However, the truth is that all such operations do alter the basic image —and that is, by definition, post-processing.
UF is shareware, unlike many other generators, which are freeware. That leaves a lot of us —whatever our reasons— with programs such as Fractal Explorer or Stephen C. Ferguson’s extensive collection. Despite being single-layer generators, these tools boast excellent features and have introduced many new filters and coloring algorithms. Still, there are layering alternatives: simply pair them with a graphics editor with layers support, and there you go: UF-like results with just a few extra mouse-clicks. Let’s see how to do some basic steps.
Choosing a graphics editor
First things first: check whether your graphics editor supports layers. Popular options include the well-known Paint Shop Pro (PSP), Corel Photo Paint and Adobe PhotoShop. The last one is quite expensive, but it has a more affordable sibling called PhotoShop Elements —a trimmed-down version with helpful walk-throughs for less experienced users. For this tutorial I’m using PSP because I already have it.
Corel Photo Paint uses the term “Objects” instead of layers, so whenever I mention a “layer” just substitute it with “Object”.
There are other excellent freeware graphic editors with layer support. One worth checking out is Pixia, a well-rounded free package that handles layers and then some. Also consider PhotoFiltre (go for version 7, which is freeware —later versions are shareware) and MyPaint. The latter isn’t as intuitive as other similar packages (at least in my opinion), but it’s excellent for mouse painting or a tablet. Pixia, on the other hand, comes packed with lots of extras for photo manipulation. Of the three, MyPaint offers the most layer blending options (over 16 of them), while PhotoFiltre has 12 and Pixia provides 11.
For Linux family users, GIMP has long been the standard. This gem is also freely available for Windows and MacOS, offering nearly the same power and tools as commercial packages. Although it’s very stable, it’s continuously under development, so get the stable version as a safety precaution. I’ve been running the Windows version for ages without problems. When it comes to layers, it offers almost 40 blending modes, more than enough to play with.
Krita is another platform-crossover from the Linux world and a great alternative to GIMP. It may not look as feature-heavy at first glance, but it works just right. In terms of layering options, no other graphics editor tops this one. With more than 60 blending modes, you might end up spending more time trying them than creating your base images —consider yourself warned. Fortunately, it lets you to keep track of your favorite picks, so you don’t have to sift through all of them every time you want to do a quick or simple edit.
Creating the images
Once you’re sure your software supports layers, create the fractal images you’re going to blend. Using your favorite single-layer fractal program, generate the master image. I have chosen Stephen C. Ferguson’s Tiera-Zon for this tutorial for several reasons: it’s one of the best fractal generators around, it’s quite fast, and it comes with lots of formulas and color algorithms. Additionally, there are several online tutorials for this program in case you need some extra advice on how to use it. See the Fractal.nfo section for more information.
Tiera-Zon opens up with a thumbnail-size “prototype” of the classic Mandelbrot set (1). Enlarge it to at least 320×240 pixels (or up to 640×480 on a fast computer) to facilitate your search. To resize, use the XY icon on the toolbar or select SIZE from the WINDOW menu. Start by searching for an eye-catching motif near the borders. For example, go to the larger bug in the front antenna-like spike (2), and from there, jump to the Elephant Valley (3). Use the following picture as a guide for steps 1, 2, 3.
Zoom around a little until something intriguing pops up. Then, save it; that will be your first image.
For this brief tutorial, we will stick to a few basic procedures. Keep working with that same motif by applying different filters and coloring algorithms to create new variants. Remember to save each new image under a different name to avoid overwriting the previous parameter settings.
Repeat the same process as many times as you like until you come up with a couple or so images to work with.
Layering
After gathering your set of pictures, render each image two or three times larger than the size you plan the final picture to be, as we’ll be applying anti-aliasing before proceeding further. Then, save them again.
Tiera-Zon has its own anti-aliasing filter (found under the Convolve menu), but we’ll use the graphics editor for this task. So, close the fractal generator and open the bitmaps in your favorite graphics editor. Resize each image to a third of its original size using the RESAMPLE option (Smart Size in the Resize Type drop down list if you’re using Paint Shop Pro). This step can be done after combining the layers, but we’re doing it now to speed up the process a little bit. The result is known as anti-aliasing, a software technique that eliminates the jagged edges (the stair-steps appearance) that appear in images when viewed on-screen.
In this case, the trick is to use color information to compensate for the lack of resolution. A fractal’s complexity goes far beyond the size of a single pixel, which prevents us from seeing all the details that constitute the image. As a result, instead of a sharp and smooth appearance we get a rough or jagged one. Anti-aliasing softens the contours of the image, allowing for a clearer appreciation of the fractal structure.
After anti-aliasing, apply any filter or enhancements you wish (that is optional). And don’t forget to save your work.
Now, we’re ready to use the layer options. As one of the most powerful and useful tools in any digital artist arsenal, layers can achieve a wide range of effects. However, we’re only going to explore the basics for now. Afterwards, feel free to try other alternatives to expand and improve the results.
Using the Copy command, copy one of the images to the clipboard. Then, select the other image, and under the Edit menu, go to Paste and choose Paste as new layer (Corel Photo Paint users: remember that the corresponding command is Paste as new object). By doing this, the first picture becomes the background image, while the copy of the other picture, now layer one, will cover it completely.
Next, open the layer properties dialog box (under the Layers menu) or the floating Layer Palette (available under View > Toolbars), and choose the blending mode you want to use to combine the two images. Try all the available options to preview the changes that will take effect after making your final selection. Click OK when satisfied.
For this exercise, I merged, or flattened, the images whenever I applied a new layer. However, it’s possible not to merge them or only merge the visible layers to produce various effects.
Another way to mix two images together is by using the Arithmetic command under the Filters menu. In Paint Shop Pro, this method will automatically generate a third image (this will not affect the original ones), but it’s not as easy or convenient as using layers. Since there’s no way of previewing the changes, you’ll need to know what you’re doing or rely on trial and error.
The picture
By now, you may have finished the basic layering process and blended at least two images to create a more complex, detailed and artistic one. Keep in mind that saving the final file in a lousy format, such as JPG, will merge all layers together. To keep them separate, save the file in Paint Shop Pro’s native format (PSP).
Voilà: that’s all it takes. Now, sign your valuable piece of art (using the text tool in your editor) and post it to your website or the alt.binaries.pictures.fractals newsgroup for the entire world to see.
Illustrated step-by-step
Image variants
This is same image with different filters and coloring algorithms in Tiera-Zon:
Final image
Merging reproduction
Of note (2017.01.03): With all probability, some fractal generators and graphics editors mentioned in this article are no longer available or are not compatible with Windows 10 or later, so don’t pay too much attention to software names. However, the tips are still valid today as they were in the past.
Update 2025.04.18: Removed references to Ultimate Paint and PhoXo because I wouldn’t recommend using either of them today.