This has become a real mantra for me when teaching. Photoshop by nature is quite a destructive application. It is easy to, in a few simple steps, irreversibly damage an digital image if we use Photoshop in the way that seems initially intuitive. Non Destructive Editing is a method of working in Photoshop that leaves the original image untouched and prevents us from progressive striping information from the digital file. Layers, Adjustment Layers and Layer Masks are key elements in this way of working.