Canon PowerShot G10 User Manual page 193

191
You cannot add effects to RAW images using the My Colors
function.
When there is not enough space left on the memory card,
the My Colors effects cannot be added.
Although My Colors effects can be added any number of
times to an image, the image quality will gradually deteriorate
with each application and the intended colors may not be
achieved.
Color in images taken using My Colors (p. 146) in shooting
mode and images edited with the My Colors function in
playback mode may differ slightly.