Android 6 / Marshmallow, grayscale mode through accessibility setting also through developer mode

Lenovo K3Note quick setting for enabling gray scale mode/monochrome/Black on white mode in Android 6 Marshmallow, also learn how to make shortcut of accessibility setting on Home screen for quick access to color correction mode.

• How to turn on Gray scale mode in android 6 / Marshmallow easy setting
• Enable through developer mode setting for older version of Android
• How to make accessibility setting shortcut for quick enable disable gray-scale mode