Channel Masking is an extremely swift and effectual method for selecting a subject with a reasonable color contrast to the surrounding pixels is to create a mask and then to load this mask as a selection.
Channel masking is commonly used for translucent or semi-transparent images like glasses, hairs, feathers, smoke, flames, highlights, lighting, chiffon & muslin, etc. Channel Masking is quite handy for saving a selection for large image files and where creating an image layer is quite difficult.

Channel Masking is Raster Masking in Adobe Photoshop that requires Photoshop Masking techniques with CMYK, RGB, and various other custom channels. The main function of channel masking is color separation, color correction etc.