The main purpose of alpha channel

The main purpose of the alpha channel is to store and set the selection range. Purpose of alpha channel: storage and selection range; In addition, you can also protect the constituency. You can also save the selection as a grayscale image, so that we can modify the selection by editing the Alpha channel with tools such as brushes, brightening, deepening and various filters. The Alpha channel refers to the transparency and translucency of the picture. For example, for a picture stored with 16 bits, 5 bits are red, 5 bits are green, 5 bits are blue, and 1 bit is alpha. In this case, it is either transparent or opaque. An image stored in 32 bits, with 8 bits representing red, green and blue. Usage: When the Alpha channel is painted with white, the selection range can be expanded; When the Alpha channel is painted black, the selection range can be narrowed; When the Alpha channel is drawn in gray, the feathering range can be increased.