Now to the Microsoft alternative. Called Windows Media Photo, it will be supported in the company's forthcoming release of Windows Vista and be made available for Windows XP. This is no guarantee it will ever reach the web, because of patent and licensing issues. Microsoft are not known for releasing products for free worldwide use. However, the company is actively marketing the format to digital camera manufacturers, and others, in the hope that it's software support (only under Windows of course) would swing the sale.

Microsoft recently presented the format at the Windows Hardware Engineering Conference in Seattle. Bill Crow, program manager for Windows Media Photo showed an image with 24:1 compression, compared to images compressed at the same level under JPEG and JPEG 2000 formats. Whilst the image reportedly contained more "more detail" it was also "somewhat distorted" because of the high compression level. Crow went on to claim that whilst digital cameras currently use a 6:1 compression ratio, Windows Media Photo "should offer better pictures at double that level". "We can do it in half the size of a JPEG file", Crow said.

In general, compression is a positive thing, until you reach the point where either image artifacts (faults) or distortion becomes apparent to the eye. Everything, including data transfer and printing is faster using a compressed image. Other benefits cited included the ability to rotate and resave an image without decoding and encoding it, "smart" compression technology and more.

I did some testing for Desktop Magazine in Australia in the late 1990s, using stock library images, for an article on the use of JPEG in commercial printing. The magazine was printed at 150# (150 dots per inch), so the images were prepared at 300ppi (pixels per inch) at actual printing size. The images were then saved in Adobe's EPS format using JPEG compression, at "maximum", "high", "medium" and "low" qualities. The four images were placed on the page one under another and the magazine printed.

Believe it or not, even under a magnifying glass, there was no discernible difference between the images to the eye. In commercial printing, which has an 8bit limit of 256 greyscales per colour, there is simply no place for 16bit images. Most printing presses also respond poorly to minimal colour changes, producing no difference on paper. In fact, it can sometimes take as much as a 3-5% change in any single CMYK colour to create a discernible colour change in a mixed tint. A printer friend of mine once told me he thought only about 15,000 clearly different colours were possible on his Heidelberg press. So much for the 16.7 million colours you can purportedly see on your 24bit monitor.

Resolution is a vital element with any printer, and the math is important. Just as you should use a resolution exactly double the screen ruling used on a commercial press, the same basic rule of image preparation applies to any printer; either a 300dpi laser or a high resolution Epson dot matrix printer. Let's use the Epson as an example. In reality, preparing your images at the highest resolution possible on an Epson printer (say 1440dpi) is simply wasteful. It is far better, and much faster to size the image to either 720ppi or even 360ppi at actual printing size and print these. Note that these image resolutions equate to half and quarter of the higher print resolution. Try it. I'll be surprised if you can tell any difference.

When using a 300dpi laser printer though, avoid making your images any larger than the available resolution, as laser printers do not always benefit from any extra resolution, as they have poor screening (halftone) algorithms. Also try 150ppi at actual printing size. Again, you may not be able to tell any difference.

Now back to the web. Could the new Microsoft format benefit web developers? Possibly, if the hype is true. But will Microsoft release it as a royalty and license-fee free product? I doubt it. This may kill the product stone-dead, as it is unlikely that Apple or Adobe will be keen to pay Microsoft licensing fees for something they don't need. There is also the question of web standards. The World Wide Web Consortium is not keen on formats that are licensed. Perhaps it's time the JPEG people got back to work and updated JPEG 2000? At least we know we would get an update for free...

• Microsoft shows off JPEG rival
• Windows Media Photo Specification
• JPEG 2000 standard
• Graphics on the Web (World Wide Web Consortium)