Open the file, in fact, any color image can do this exercise.
Open the layer panel, click the new layer icon below for 4 times to generate 4 new layers, namely, layer 1, layer 2, layer 3 and layer 4.
Load channel selection
Open the channel panel. Click the mouse on the red channel and select the red channel as the current channel.
At the bottom of the Channels panel, use the mouse to load the channel selection icon and view the ant line in the image. This will load the red channel selection.
Click the RGB composite channel, all channels are activated, and then you can see the normal color image again.
There are often friends who click the eye icon in front of RGB channels with the mouse in this step, so that only three channels are visible, but not three channels are opened. This is not right. Three channels must be open and all three channels are active on the channel panel.
Fill color
Return to the Layers panel and specify the top layer 4 as the current layer.
Click the foreground color icon in the toolbox, open the color picker panel, set the RGB colors to R255, G0 and B0, which are RGB pure red, and click OK to exit.
four
Press Alt+Delete to fill layer 4 with red foreground color. The red layer, which is all red in the original image. If you temporarily turn off the background layer, you can clearly see all the red effects in the image.
Make green and blue layers
Then make a green layer.
First, you must close layer 4, confirm that the background layer is open, and the image will return to normal color effect. Press Ctrl+D to cancel the existing selection.
Open the channel panel again.
Click to select the green channel in the channel panel.
Load the green channel selection in another way. Hold down the Ctrl key and click the green channel, so that the selection of the green channel is also loaded, and the ant line can be seen in the image.
Click on the RGB composite channel, all channels will be activated, and the ant line will be seen again.
Return to the Layers panel and specify Layer 3 as the current layer.
Click the foreground color icon in the toolbox, open the color picker panel, set the RGB colors to R0, G255 and B0, which are RGB pure green, and click OK to exit.