Canon 10D User Guide (en)

Modulation and degree of contrast can be adjusted. Move the slider to 
the right to make contrast stronger and to the left to make contrast 
Adjusting Contrast
Reverts the image to 
the original settings
Drag the slider left or 
right (9 steps)
Use [Linear] when you will be adjusting separately using image editing 
software that has advanced editing functions. Note that when [Linear] is 
checkmarked, the image will become dim.
[Linear] - A function for advanced adjustment
Skin tone and overall color saturation can be adjusted.
If Picture Style 
 is set to [Monochrome], [Color tone] and [Color 
saturation] switch to [Filter effect] and [Toning effect] 
Color tone:
Mainly used for adjusting skin tones. Move the 
slider to the right to make skin tones more 
yellow, and to the left to make skin tones 
Color saturation: The overall color depth of the image is 
adjusted with color saturation. Move the slider 
to the right to make the color deeper, and to 
the left to make the color weaker.
Changing Color Tone and Color Saturation
Drag the sliders left or 
Display the values of the settings
Reverts the image to 
the original settings
The adjustment range is –4 to +4 (in 1-stop increments).