The Hue/Saturation command adjusts the hue, saturation, and brightness of an image.
Hue is the colour; Saturation is the strength of the colour. Lightness is the relative lightness or darkness of a colour.
Adjusting Hue/Saturation
Choose Image > Adjustments > Hue/Saturation.
The top colour bar displays the colour before the adjustment. The bottom bar shows the adjusted colours.
(Optional) Select the colour to adjust from the Edit menu:
Select Master to change all colours.
Select one of the preset colours in the Edit menu to adjust that colour.
Drag the Hue slider to modify the colours.
Drag the Saturation slider to the right to increase saturation or to the left to decrease saturation.
Drag the Lightness slider right to the right to lighten or to the left to darken the colour.
Alternatively, you can select one of the Presets at the top of the dialogue box to create a predetermined effect. You can also save any of your own settings as a Preset by choosing Save Preset.
Instead of using the Hue and Saturation sliders, you can use the On-Image Adjustment tool. Click this tool and drag horizontally on the image to alter the saturation of the pixel colour you click on. Note, this tool automatically reads the pixel colour you click on, for example if you click on red, it will switch from "Master" to "Red". Ctrl drag (Windows) or Command drag (Mac OS) on the image to alter the hue.