Mandelbulber Tutorial: Rendering High-Res Images
G’day. This post will be a little early in publishing, seeing that I’ve yet to post Basic Settings II and III in this series, but don’t worry: I’ll link back to this entry from those when they are published. Otherwise, this entry assumes some ability or prior experience with using the Mandelbulber app, created by Krzysztof Marczak, for generating fractals, and this will be more of a mini-tutorial for tips and suggestions on producing very large and high resolution images starting with the basic app (here using version 1.16 for the Mac) and after the initial rendering of the image, using suitable editing and viewing software like Apple’s Preview for OS X.
You may want to refer to the first installment in this series if you’re new to the software, for the very basics.
First, start out with image dimensions of 400 x 400 pixels for exploratory purposes. It lets you zoom into a fractal surface using a quicker rendering speed with each mouse click, and you can then increase the pixel size of the image for particularly promising regions of the figure for rendering a larger piece more clearly.
What happens next? Assuming you’ve found a really cool region, as I often do, after increasing the size of the image in pixels (the default resolution for images generated with Mandelbulber is 72 pixels/sq. inch) you may want to make a higher-resolution, good print-quality image for a display piece, about 300 pixels/sq. inch, at a size, say, of 5×5 ft when fully printed. Given the desired resolution, this will be an enormous image at the default resolution, and as you may guess, the image shrinks when resolution goes up, from 72 to 300. Low res, high pixel-size images can be gigantic. Figure 1 shows the values one can enter for such an image starting out, set before clicking the ‘Render’ button:
In this case, I input a value of 18,000 x 18,000 pixels, keeping all other values the same, except for Figure 2, on the ‘Engine’ tab, where I input the ‘Detail level’ needed to keep the image proportionate and the app from getting cranky and quitting on me from the workload I’m imposing on it. Starting out, at 72 px/sq, inch, this would be a truly huge image. I’ve input the Detail level at 0.022 from a starting point of 4.0 at size 400 x 400.
Detail level must always be reduced in proportion to the image size, otherwise it makes the image ‘noisy,’ and cluttered-looking when rendering is complete. Once the rendering process is underway, extremely large images may take several hours to fully process — this is a far cry from generating mere cool-looking wallpaper or Tumblr posts to share online!
Once the image is fully rendered, you can save it as a JPEG, or several types of PNG file, either to your desktop or to a folder you’ve selected. Now it’s time to both reduce the image size and increase the resolution to make the image more printo-genic.
In my own attempt, Preview read the file as somehow being even more insanely huge than I had intended, at 75,000 x 75,000 pixels(!!!) at 250 inches across, so I first reduced it and then edited the pixel density from 72 to 300, shrinking the image considerably from a good-sized mural to a printout size of 5×5 feet, good enough for a wall-hanging or museum piece, all other things being equal. I came very close to making the viewing/editing software seize up and die on me, but it worked, and the image below is a 600 x 600 px thumbnail of the result, the original image itself maddeningly large for upload or email barring unforseen technical advances, taking up 174 MB of space [Update], though as an afterthought, Dropbox and similar filesharing services could manage it:
So it worked, which is good. May your own efforts turn out at least as well as mine did, and happy fractaling!