Detailed illustration of lab channel color grading

<This tutorial only briefly explains the color adjustment method of the lab channel. In fact, there are more channels in RGB and CMYK colors to produce richer colors>
Original picture

final effect


1. Open the original image, select the menu: Image > Mode > LAB Color, and then click on the channel panel as shown below. We will find that there are two gray channels a and b below. We first click on the a channel and then press Ctrl + A to select all. Press Ctrl + C to copy, then click on the b channel and press Ctrl + V to paste back to the layer selection menu: Image > Mode > RGB Color to get the effect of Figure 2

<Figure 1>

<Figure 2>

2. In the same way, if we copy channel b to channel a, we will get different effects.

<Figure 3>

3. In fact, using channels in RGB and CMYK colors can create more effects. For specific methods, please refer to: Photoshop tutorial on playing with channel coloring.