A reader asks,

“I’m thinking of entering [an image in a competition]. The rules state that I can send jpg images on a CD but that they must be in RGB format and not CMYK format. When I capture images on my Canon S2IS what colour format does the camera use? If I use Picasa as my photo program does it use CMYK (I know most printers use these colours)? If I have a jpg image, can I use something like Photoshop to convert from CMYK to RGB?”

Virtually every digital camera on the market produces image in the RGB colour space, so the good news is that you don’t have to do any conversion.  People are often confused by the fact that their inkjet printer uses a CMYK process.  However, the printer appears to your computer as a RGB device, as does your monitor, so you should continue to work in the RGB colour space unless there is a specific reason for you to convert to a different colour space.