Back in the old days, when Ultra Fractal (UF) was nowhere to be found, all the available fractal generators produced single-layer images, and most of them still do so. Only UF incorporated image manipulation options, such as layers and alpha channels, as found in graphics editor packages. Since then, there’s no need to leave the program to post-process the picture (unless you want to add text, apply special filters or combine extra graphical elements). These unique features are responsible for the increase in popularity of this generator among fractal enthusiasts.

Usually we say a fractal image has been post-processed when it has been imported into a graphics editor to adjust any of its original properties. That results in a modification of the master picture as it came out of the fractal generating software alone. This is a normal practice in digital graphics creation, but still divides the group of fractal artists into camps: those who prefer to leave the fractal as is (keeping its natural form), and those that routinely enhance its appearance with the intent of improving or increasing the artistic output. UF helped to change that perception because most fractal artists are using it almost exclusively, unleashing its power to mix layers into a single image. Since all adjustments are done inside the same application, some people think they’re not post-processing the picture, but the truth is that all those operations are altering the base image, and that’s normally called post-processing.

UF is shareware, as opposed to other generators, which are freeware. That leaves a lot of us, for whatever our reasons, with programs such as Fractal Explorer or Stephen C. Ferguson’s extensive collection. Notwithstanding their excellent features, these are single-layer generators that have introduced a lot of new filters and coloring algorithms. Nevertheless, there are layering alternatives for them: just 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 if your graphics editor supports layers. In that group are the well-known Corel Paint Shop Pro (PSP), Corel Photo Paint and Adobe PhotoShop. This last one is the most expensive of the group (and most people may prefer to avoid it), but it has a junior sibling that goes by the name of PhotoShop Elements, which is a trimmed-down version with walk-throughs suitable for less knowledgeable users. For this tutorial I’m using PSP because I already have it.

PSP layering window
JASC Paint Shop Pro 6 working window (software circa 2000, current version X9 owned by Corel, may differ greatly).

Corel Photo Paint prefers the term “Objects” instead of layers, so, whenever I say “layer” do an automatic mental switch to “Object”.

There are other very good freeware graphic editors with layer support. One to look for is Pixia, an nice free package that handles layers and then some. Also take a look at PhotoFiltre (go for version 7, which is freeware; later versions are shareware) and MyPaint. The latter is not as easy to use as other similar packages (at least not in my opinion), but is excellent if you want to try mouse painting or using a tablet. The first one, on the other hand, comes with lots of extras for photo manipulation. Of these three, MyPaint has the most layer blending options (a whooping 21), while the other two have fewer modes: twelve in the case of PhotoFiltre and eleven for Pixia.

Ultimate Paint could be an extra option. It doesn’t include layering assistance, but its arithmetic filter will do a similar, although more limited, work. There’s also a “beef up” share version of this editor that comes with some extra filters and functionality. You might also consider PhoXo too, a simple graphics editor that supports layers, but only allows merging with varying opacity levels.

For Linux family users, the standard has always been the GIMP. This gem is also freely available for Windows and MacOS, with practically the same power and tools of commercial packages. Although it’s very stable (so far I’ve had no problems using it on my PC), it’s continuously under development, so be careful, or do not install if you have any doubt. I run the Windows version without problems whatsoever. In the layering field, it comes with 22, enough to play with.

Krita is another platform-crossover from the Linux camp, and a very nice alternative to GIMP. It doesn’t look as finely finished, but does the work just right. In terms of layering options, no other graphics editor tops this one. With close to 80 modes, you’ll be spending more time trying them all than creating your base images, so be warned. Fortunately, it lets you keep track of your favorite picks, so you don’t have to go through all of them every time you want to do more quick or simple tasks.

Creating the images

Once you’re sure your software support layers, create the fractal images you’re going to blend together. 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 generators around, it’s quite fast, and it has lots of formulas and color algorithms. Also, there are several online tutorials for this program, in case you need some extra advise on how to use it. See the Fractal.nfo section for more information.

Stephen C Ferguson's Tiera-Zon 2.8
Stephen C Ferguson’s Tiera-Zon 2.8

Tiera-Zon opens up with a thumbnail-size “prototype” of the classic Mandelbrot set (1). Enlarge it to at least 320×240 pixels to facilitate your search. To do so, use the XY icon located in the toolbar or select SIZE from the WINDOW menu. Start by looking for an eye-catching motive near the borders. For example, go to the larger bug in the frontal antenna-like spike (2), and from there, jump to the Elephant valley (3). Use the following picture as a guide, as steps 1, 2, 3.

Mandelbrot set

Zoom around a little until something intriguing pops up. Save it because that will be your first image.

For this brief tutorial, we will circumscribe to a few elemental procedures, so keep working with that same motive, applying different filters and coloring algorithms to create new variants. Remember to always save the new image under a different name since you won’t wish to overwrite the previous parameter values.

Repeat the same process as many times as you want, until you come up with a couple or so images to work with.


After getting the set of pictures, render each image two or three times larger than the size you plan the final picture to be because we’re going to anti-alias them before going any further. Then save them again.

Tiera-Zon has its own anti-aliasing filter (look for it under the Convolve menu), but we’re going to use the graphics editor to do that task. Thus, close the fractal generator, and open the bitmaps in your favorite graphics editor. Resize each picture to a third of its original proportion using the RESAMPLE option (Smart Size in the Resize Type drop down list if you’re using Paint Shop Pro). This procedure can be done after combining the layers, but we’re going to do it now to accelerate the process a little bit. The result is what’s called anti-aliasing, a software technique that eliminates the jagged edges (stair steps appearance) that show on images when viewed on-screen.

In our case, the trick is to use the color information to compensate for the lack of resolution. A fractal’s complexity goes far beyond the size of a single pixel. That deprives us of seeing all the details that constitute the image, so instead of a sharp and smooth appearance we get a rough or crappy one. Anti-aliasing softens the contours of the image, allowing us a clearer appreciation of the fractal structure.

After anti-aliasing the images, apply any filter or enhancements you care of (though that’s not a must). And don’t forget to save your work.

Now, we’re ready to use the layer options. Being one of the most powerful and useful tools in any digital artist arsenal, there are a lot of effects that can be achieved using layers. However, we’re only going to explore the basics. Afterwards, you can try other alternatives to expand and improve the results.

Using the Copy command, place a copy (what else) of one of the images to the clipboard. Then, select the other one, and under the Edit menu, go to Paste and choose Paste as new layer (Corel Photo Paint users: remember that the corresponding command must be Paste as new object). By doing this, the first picture becomes the background image, while the copy of the other picture, now layer one, should cover it completely.

Layer properties window
Layer properties window

Next, open the layer properties dialog box (under the Layers menu) or the floating Layer Palette (look for it under View/Toolbars), and pick up the blending mode you want to use to combine the two images. Try all the available options to see a preview of the changes that will take effect after making your final selection. Click OK when ready.

For this exercise, I merged, or flattened, the images whenever I applied a new layer, but it’s also possible not to merge them or to merge only those that are visible to produce varied effects.

Layers window
Layers window

Another way of mixing 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 the layer options. Since there’s no way of previewing the changes, you must know what you’re doing, or go by trial and error. Yet, that’s the only possibility in Ultimate Paint. This editor, as has been pointed out already, doesn’t include a layering command, but thankfully offers a preview pane in the Arithmetic dialog box.

The picture

By now, you might have finished the basic layering process, and might have blended at least two images together to produce a more complex, detailed and artistic one. Realize that saving the final file to a lousy format, such as JPG or GIF, will merge all layers together. To keep them separated, 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 of your editor) and post it to your Web site or to newsgroup for the entire world to see.

Illustrated step-by-step

Base image
This is the base image, from where all the others came from.

Image variants

This is same image with different filters and coloring in Tiera-Zon:

Resulting image

A mix of five layers of Tiera-Zon fractal images.
A mix of five layers of Tiera-Zon fractal images.

Merging reproduction