What is the difference between PS calculation and application image?

1. The main difference is that the calculation command will generate a new channel without changing the current layer, and the applied image will directly act on the current layer.

2. The second difference is that there are more choices for computing channels of computing commands, such as "gray" and "transparent", while the application image only has the choice of composite channels and color channels (the composite channels are determined by the image mode, such as RGB mode, and the composite channels and color channels are RGB, R, G, B G, B).

3. Calculate the difference of arrangement: For example, for a color (such as R 197 G79 B0), select the red channel to execute the application image of green 100%, and the new red channel obtained is the source 1 green+source 2 red (strong light 100%) in the calculation command.

My humble opinion, welcome to correct and discuss.