Huawei Mate 8 - Manual (Page 208)

Accessibility features
201
1
Open Settings.
2
Touch Advanced settings > Accessibility > Touch & hold delay.
3
Select the desired delay time: Short, Medium, or Long.
Color correction
Color correction mode adjusts colors to make it easier for color blind users to distinguish
between different parts of the screen.
Use this feature with caution. Color correction is designed for visually impaired users
and may affect your phone's performance.
1
Open Settings.
2
Touch Advanced settings > Accessibility and then turn on the Color correction switch.
3
Touch Correction mode, and then select a correction mode.