Transcript
          
          
            Many people who use Photoshop tend to make adjustments by going 
            to the Image -> Adjustment menu and choosing things like Levels
            which you use to change the lighting of the image. Adjusting 
            points on the graph change the lighting.
          
          
            The problem with this approach is that this adjustment is now applied
            to the image, so when we go to adjust things like the exposure of the 
            image, which we can do from the same menu, then the changes we make 
            to the exposure are being made on the image we have already adjusted.
          
          
            There's a better way to to this, by using Adjustment Layers. 
          
          
            We'll revert this image, and then we'll make a new adjustment layer
             for the Levels. This interface looks exactly the same as the previous.
          
          
            We adjust the points on the graph and see the changes to the 
            image in real-time.
          
          
            Then we can add another layer for the exposure. When we make changes,
            they're applied independently to the image.
          
          
            We can always come back and adjust these at any time, and we can 
            toggle them on and off when we don't need them. This is a great 
            way to adjust images non-destructively.