Adjustment Layers

Adjustment Layers


The above palette shows an example of an adjustment layer (called Levels 1). By clicking the adjustment layer button, you can add an adjustment layer to any image and make adjustments that will be separate data from the image itself. This can give you the opportunity to remove the adjustment later, or blend it with the original, or change it from what it was.


 
Notice here that the adjustment layer (on top) has been hidden because the eyeball is missing (clicked on).   Notice here that the adjustment layer (on top) has now been set to visible, and you can see how it has affected the image.

Probably, one of the most useful aspects of adjustment layers is the fact that their opacity can be changed to any degree. This is especially useful for adjustments, such as Auto Levels, or Auto Contrast, which automatically adjust your image, but can sometimes go too far.

Adjustment Layer Masks

Another feature of the adjustment layer is that it automatically contains a "mask" that will allow you to modify the regions on your image where the adjutment will and will not happen. It works much the same way as the Quick Mask Mode because it is editied by painting black or white depending on the effect you want.

 

Here's the original of the image before we add an adjustment layer that allows us to use the Levels to darken the entire image. Notice that it is all white by default--this means that it is not affecting the adjustment layer.

Here, I've clicked on the adjustment layer mask so as to activated it. You can see an icon to the right of the eyeball in the layer that tells us we're now in "Mask Editing Mode" and when we paint on our image, we're actually painting on the mask itself.

So I choose the paint brush tool, with the foreground of black, and an appropriate brush size. As I paint black on the mask I can see that it hides the effect in those areas.