BY the end of the month, Hong Kong photographers will be able to store photographs on compact disc (CD). CDs are now a regular part of many people's lives, and when Kodak announced its Photo CD technology in 1990, it was a logical development of the disc's ability to retain data. Photo CD allows photographers to store photographic quality images on a CD by digitising the film. The roll of film is taken for processing and, after developing the negatives, is returned to the customer, together with the ''prints'' on the CD. The system, which has been available in the United States for some time, will be operated in Hong Kong initially by Kodak, but the company is hoping to interest processing laboratories so that customers can take their film to be developed anywhere in Hong Kong. The pictures on CD do not fade over the years, and they will not become scratched. Each picture consists of 18 million pixels compressed on to the disc. This provides a video resolution 16 times greater than existing television standards and four times greater than high definition television. The technique was developed by Kodak as an answer to the competition provided by still video cameras. Kodak came up with the Photo CD after becoming concerned that the low resolution images which the video cameras displayed on the television screen would cut into the film market. In the US, it was aimed at the consumer and, while this is also the ultimate aim in Hong Kong, Kodak hopes to penetrate the professional market first. Part of the reason for this strategy is the cost. A CD can store up to 100 35-millimetre images, but each image will cost $35. In addition, to be able to view the pictures, the viewer must buy a Photo CD Player. To spread the cost, the Kodak PCD 860 can also be used to play audio CDs. A future development, which is available in the US and which is targeted at professionals, will allow graphics, text and music to be added to the image. The professional is likely to be the main beneficiary of this development, and Kodak has acknowledged this by introducing Pro Photo CD which has enhanced capabilities. The CD will accept a range of film sizes, including 135, 120 and 10 millimetres by 12.5 mm. and will support high resolution film scans up to 6,000 by 4,000 pixels. The Pro Photo CD will include a special identifier to protect copyright, and will encrypt high resolution images to prevent unauthorised use. Using a desktop computer, images can also be manipulated by removing background, or changing colour density. The Pro Photo CD has uses ranging from photo-journalism, to multimedia presentations and archiving in museums. A whole range of equipment is available so that the professional can do his own work and not rely on Kodak or any other film processor.