Home » Tip of The Day » Adding Blur and Sharpness To Channels When Creating SelectionsAdding Blur and Sharpness To Channels When Creating Selections September 21, 2015. Posted in: Tip Of The Day. When using channels to create selections, consider adding the Gaussian Blur filter to soften the edges. You can also apply the a Unsharp Mask filter to reduce the softness of edges. « Previous Photoshop Tip: | Next Photoshop Tip: » Sign-up for the PTC Newsletter so that you'll never miss a tutorial!. Your Email Address: