ARE you the kind of person who can鈥檛 bear fingerprints on your DVDs? Do you flinch when someone picks up a CD as if it were a frisbee? Then don鈥檛 lend your collection to Cameron Jones. Jones, a mathematician based at the Swinburne University of Technology in Melbourne, Australia, smears yogurt on CDs. He lets them dry, then sticks them back in the machine and presses play.
What comes out might one day make him a rich man. There鈥檚 a market for this stuff, he says. His bizarre methods could provide the newest tools in musical composition and graphic design. And anyone can try it.
So how did a respectable mathematician come up with such a crazy idea? Well, it all started with beer. After he finished his PhD, Jones opened a nightclub and bar in Melbourne. As well as serving drinks, he does a bit of DJing and video projection for the dance floor, experimenting with creating new sounds and images. It was in that bar, the Blue Velvet, that yogurt on a disc was born.
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鈥淚 often change CDs when my hands are wet with beer,鈥� Jones explains. 鈥淥ne night I must have changed the CDs, touched the data surface, then left them for use on another night.鈥� The next week, he put on a CD by Nine Inch Nails, and when it wouldn鈥檛 play properly he took it out and had a look. 鈥淲hat looked like fungi was clearly visible,鈥� he says. 鈥淚t might have been yeast, but could well have been other organisms using the beer as a carbon source.鈥�
Jones was especially intrigued because the fungus hadn鈥檛 completely ruined the CD. The original audio sequence was still there, but the music was now punctuated by small staccato noises or occasional changes in pitch. Immediately, Jones says, a question came into his mind. 鈥淲hat would happen if I purposely grew fungi, yeast or bacteria in direct contact with the media, and manipulated their fractal dimensions?鈥�
That might not be the first thought to pop into most people鈥檚 minds. But then, most people don鈥檛 share Jones鈥檚 combination of interests: his PhD investigated how signals can be transmitted through the fractal growth patterns of biological cells, while his nocturnal activities include creating experimental music for the club鈥檚 dance floor.
Experimental musicians are continually frustrated whenever they are restricted to a limited range of sounds to choose from. Just as painters mix paints and may try working in other media, musicians want to find new and exciting sounds that will stop listeners in their tracks. That鈥檚 why, when DJs began using record decks to create new effects in the mid-1980s, the DJ and composer Christian Marclay sanded and cracked records and even broke and stuck them back together again to achieve a unique sound. Today, bands like Radiohead put nail varnish or even paint onto CDs to create new sources to sample.
These techniques introduce gross defects on the scale of a millimetre or so, but the fungal growth was having a far more subtle effect. 鈥淚 knew that if I could introduce errors at the micron or nanoscale level there would definitely be new sounds and new mathematical territory to be explored,鈥� says Jones. CD and DVD players use complex error-correction algorithms to cope with dust, scratches or grease on the optical surface. The mathematical routines that process the data on the CD can, to some degree, make up for missed bits as the laser scans. But by creating defects on a new, finer scale, Jones produced unprecedented results: and he discovered that organisms growing on the CD could actually 鈥減rocess鈥� the information on the disc.
The precise effect of his techniques depends on the way the cell colonies develop. Bacteria grow by cell division, while fungi grow by branching, and both processes can be controlled by adding traces of malt extract as a nutrient, changing the distribution of the initial 鈥渟eed鈥� population or varying the time, warmth or humidity.
Playing around with these enables Jones to have some say over how the CD player interprets the information on the disc. Normally the player鈥檚 laser is reflected from the disc鈥檚 surface in a way that reveals a sequence of binary digits 鈥� 0s and 1s 鈥� that encode the sound. But a particular structure in the bacterial growth can process this information, so that two adjacent bits are turned into a 0 if they are identical, and a 1 if they are different. This is what an 鈥淴OR鈥� logic gate does in a silicon microprocessor. When he noticed effects like this, Jones decided to call his CD-yogurt combos 鈥渙ptical biocomputers鈥�. He even talks about the possibility of making useful computations with the goo one day.
Meanwhile his experiments are making waves in the music world. Jones has taught some of his house DJs to use these methods, and their results are 鈥渋mpressive鈥�, he says. He has sent his creations to other DJs in the area, and they have been played on local radio. He is currently remixing a single for a local band using the fungal sound system. On his website visitors can listen to the Red Hot Chili Peppers as modulated by a Pycnoporus cinnabarinus strain. It鈥檚 not a great experience, though, even considering it is played through a fungus.
Visual artists can also hope to benefit from nanometre-sized assistants. Jones is exploiting the visual effects of fractal fungal growth on computer CDs storing graphics and artwork. These 鈥渂io-rendered鈥� graphics could provide an entirely new tool for graphic designers. Just as the audio files remained largely recognisable, digital images retain much of their integrity while being pulled apart, with parts copied and displaced around the screen in weird ways (see Photos, above). Watching the effect is surprisingly absorbing.
And anyone can try it. Jones has employed a variety of bacterial and fungal cells, but the easiest way to start, he says, is with a live, runny yogurt like the drinking variety available in some supermarkets. Streak it over the CD or DVD surface and leave the disc to dry in a warm, humid environment. Stick it back in the machine (at your own risk, of course), and press play. Another group of people 鈥� secret agents 鈥� might have a different application. Grow your bacterial coating on a blank CD, then write data onto it. Now wash the bacteria off, and the CD is unreadable. Let the bio layer grow back under similar initial conditions and you can read the CD without error. Or that鈥檚 the idea. 鈥淪ometimes this works and sometimes not,鈥� Jones admits. But how long will it be before secretive children take this forward? Where their parents grew up making invisible ink with lemon juice, today鈥檚 creative kids could hide their computer files using a tub of yogurt and a rewritable CD.
If the idea sends parents into paroxysms over what might become of their precious hi-fi systems, don鈥檛 despair: Jones says he has not yet damaged any of his discs or players. The technique does crash CD players on computers, though, because the software can鈥檛 cope with what the bacteria do to the music. And if the sound of the Red Hot Chili Peppers modulated by a Pycnoporus cinnabarinus strain is anything to go by, I can鈥檛 say I blame it.
