Canon EOS Rebel T5i 18-55mm IS STM Lens Kit Manual (en)

You can select the color display mode which will be the basis for color 
adjustment from three options (HSL, Lab, or RGB) as well as checking 
values for adjusted colors.
When “HSL” is selected for the color display mode, you can only 
change the color value for before adjustment by entering a 
Color Display Mode
Switches the color display 
Color value before adjustment
Color value after adjustment
HSL is a color display mode using the three elements of hue (H), 
saturation (S), and luminosity (L).
Lab is a color mode developed by the CIE (Commission 
Internationale d’Eclairage) where L is for lightness, a for color 
elements from green to magenta, and b for color elements from 
blue to yellow.
RGB is a color display mode using red (R), green (G) and blue 
(B), the three primary colors (additive colors) of the visible light 
You can adjust the brightness and contrast for the luminosity of the 
entire image using the tone curve. To further adjust contrast and 
brightness after adjusting image characteristics with the [Six Color-
Axes] tab sheet or [Specific Colors] tab sheet, use the tone curve in this 
[Specific Colors] tab sheet.
Adjust the brightness and contrast.
The brightness and contrast of the image change.
The horizontal axis shows the input level and the vertical axis 
shows the output level.
The maximum number of [
] is 10.
To delete a [
], select the [
] and then either press the <Del> 
key on the keyboard or double-click on the [
Adjusting the Gamma Characteristic for Luminosity
Click to add a [
(adjustment point) and 
adjust by dragging
The value of the 
selected point (you can 
also enter numerical