Cheap eye-candy

Mandelbrot pictures

These pictures have been rendered with the program mandel.c. The program now includes a new anti-aliasing algorithm which significantly improves picture quality over a regular averaging algorithm. The pictures below were rendered with 25 (5x5) samples per pixel.

mandel2 thumbnail Mandel2 (369K) mandel3 thumbnail Mandel3 (456K) mandel4 thumbnail Mandel4 (381K) mandel5 thumbnail Mandel5 (518K) mandel6 thumbnail Mandel6 (381K) mandel7 thumbnail Mandel7 (291K) mandel8 thumbnail Mandel8 (237K) mandel9 thumbnail Mandel9 (437K) mandel10 thumbnail Mandel10 (667K)

Colour hardcopies

Using a camera, you can obtain colour hardcopies which are on a par with that of colour printers. You need a camera with user-definable shutter time and tripod, and a high-resolution monitor. Good results were obtained with photographing the monitor in a dark room. The brightness of the monitor was approximately normal. The aperture should be as small as possible to maximise sharpness. The shutter time should be about 1-20 seconds when using normal-sensitivity (100 asa) film. You should even be able to make out the monitor's dots on the photographs, if they are large enough (e.g. more than 10 inches across).

Video projection

Video projectors typically cost thousands of guilders. There is a simple trick, however, with which you can build a video projector for approx. fl.12,50, more than a hundred times cheaper! This idea was taken from Noah Spurrier, who invented a projection device called the Warper. The idea is very simple: one puts a lens in front of a regular computer monitor, and the screen is projected onto the opposite wall. My first experiments were with a round coffee pot, which worked, but with less-than-optimal results (only the centre is in focus).

The Warper uses a fresnel lens. Fresnel lenses are perfect for this application: they are cheap, and have high light yield. Fresnel lenses were originally invented for use in light houses, but nowadays they are also found in overhead projectors, back windows of cars and buses, and in various lighting equipment. The building instructions for the Warper also mention some companies where they can be bought. However, they may also be found at your local optician, in the form of magnifying sheets. Here's my easier version of `The Warper':

Buy a magnifying sheet at your optician. A sheet that's slightly smaller than A4 paper size is good for a 15 inch monitor. Bigger is always better.
Make sure your monitor faces a suitable wall. Simply holding the lens in front of your monitor will already give a good idea of the results. The distance between the monitor and the wall should be 1-10 meters. The distance between the monitor and the lens should be about 5-20 inches, shorter if the wall is closer. Make sure your room is very dark, because the light yield is low.
Obtain a sturdy pole, for example the spit from your oven or grill. Tape the sheet to the pole.
Fix the other end of the pole on top of your monitor by putting some books on top of it (make sure you don't block the monitor's vents!). Get the lens distance right.
If needed, you can reduce stray light by draping a newspaper over the monitor, pole, and lens.

I've obtained magnifications of factor 100 (10x10) with reasonable sharpness (it's possible to play video games on it). There is one snag, however... the projection is upside down!