How much information can you store on an A4 sheet? Well, according to some new technology designed by an Indian engineering student, an extraordinary 256GB.

With new "rainbow technology", devised by Sainul Abideen who has just completed an MCA degree in Kerala, data can be encoded into coloured geometric shapes and stored in dense patterns on paper.

Files such as text, images, sounds and video clips are encoded in "rainbow format" as coloured circles, triangles, squares and so on, and printed as dense graphics on paper at a density of 2.7GB per square inch. The paper can then be read through a specially developed scanner and the contents decoded into their original digital format and viewed or played. The encoding and decoding processes have not been revealed.

Using this technology an A4 sheet of paper could store 256GB of data. In comparison, a DVD can store 4.7GB of data. The Rainbow technology is feasible because printed text, readable by the human eye is a very wasteful use of the potential capacity of paper to store data. By printing the data encoded in a denser way much higher capacities can be achieved.

Update: But following this article and widespread coverage of the claims, the claimed storage technology has been widely and roundly dismissed as not possible. See our article "Can you get 256GB on an A4 sheet? No way!" for a full rundown.

We have also come across some interesting new technology from Xerox for the next generation of barcodes, where huge amounts of information are stored in a tiny readable space.

Paper is, of course, bio-degradable, unlike CDs or DVDs. And sheets of paper also cost a fraction of the cost of a CD or DVD.

Abideen has demonstrated a 45-second video clip being encoded on paper, termed by him, a rainbow video disk - RVD - and then played back through a computer with an RVD scanner attached. In another demonstration he has shown 432 A4 pages of paper rainbow format-encoded and stored on a two-inch by two-inch square of paper.

He says that smaller scanners could fit inside laptop computers or mobile phones, and read SIM card-sized RVD's containing 5GB of data.

The recording media could be either paper or plastic sheets. Such media are making a comeback - witness yesterday's story about re-writable paper.