How to Merge channels to create an alpha channel in Photoshop

One of the oldest, most abstruse, downright incomprehensible commands in Photoshop, Calculations lets you merge two channels to create a new alpha channel. Learn it: It's the backbone of masking. Whether you're new to Adobe's popular raster graphics editing software or a seasoned professional just looking to better acquaint yourself with the program and its various features and filters, you're sure to be well served by this video tutorial. For more information, including detailed, step-by-step instructions, watch this free video guide.