First open an Image in Photoshop.
To make it easy for you we have uploaded Stock image For your Practice.
Step 1, Go to Layers / New Adjustment Layer / Curves.
Step 2, Select The Channel: In this tutorial We Chose Green.
Step 3, Click on Curve Highlighted Blue Drag Them to Direction as Shown in Above Image. Click Ok and you Done !!! Here is Your Final Image.