Using Adjustment Layers
by Adrienne Cleveland
When processing images, adjustments to properties such as color balance,
levels, contrast, etc. can be make directly to the image. However,
I prefer to make these changes using Adjustment Layers, because if I decide to
edit the photo later, I can
more easily see what changes I have made, and I can undo or edit them with no loss of data.
To show what I mean about loss of data, I'll use
an extreme example of applying adjustments directly to an image:
After Lowering Contrast
Now, you'd never lower the contrast this far, but as I said, this is an
After "Restoring" Contrast
Here's the result when we try to restore the contrast. You can see that a
lot of the original data has been lost. The loss is most visible in the
sky and the reflections.
With Adjustment Layers, however, all the original
information is retained, so you can make any changes you want later, by just opening the adjustment
layer and changing the settings. You can even delete an adjustment layer and start over.
Creating an Adjustment Layer
To create an adjustment layer, you can either use the Layer menu, or click this icon in the Layers window. Then
just choose the type of adjustment you want to make, and make the changes.
After you've created an adjustment layer, your Layers window will look something like this. In this
case, the adjustment layer I created was for Selective Color.
If you want to change the settings later, just double-click on the layer thumbnail (where the red
arrow is pointing). You can then see
the settings and edit them.
Notice that the Adjustment Layer has a mask (the rectangle to the right of the layer thumbnail)
associated with it. If you want the adjustments
to apply only to certain portions of the photo, you can control that by "painting"
or "erasing" portions of the mask.
After you've made all your adjustments except for sharpening, save a copy of
the file as a Photoshop PSD file. If you discover
later that you don't like the results of your adjustments, you can easily change them
without completely reprocessing the photo.
The downside? Adjustment Layers
do make for larger files.