How do I increase or decrease filter intensity on iPhone photos?

iOS 13 has overhauled the photo editing tools interface and added a few new features, among them are intensity sliders for the filters. Just like you can adjust Brightness, Saturation, Contrast and others on a sliding scale, you now have intensity sliders for each filter. By default they start at 100 but you can adjust them all the way down to zero if you want subtler effects. When you have your desired intensity, tap Done. You can always discard your changes later by tapping Revert.