Think of adjustment layers as isolators. They protect your original data from any adjustment they represents.
First introduced in Photoshop 4, Adjustments layers tend to be a powerful tonal and color correction tool in Photoshop.
In this article I will walk you through the basics of Adjustments layers going through some advanced functions, techniques and tips about Adjustments & Fill layers.
Overview:
First you need to know that an adjustment layers affects all underlying layers. So layers stacking above an adjustment layer are far from its affect.
To create an Adjustments layer you either go to:
- Layer/ New Adjustment Layer/
- Click the New Adjustment Layer icon at the bottom of the layers palette
Adjustments layers can be created in Photoshop only and not in Image Ready, although they can be viewed in Image Ready.
When using Adjustments layers you are not only isolating any changes you made from the original data but also affecting multiple layers with only one Adjustment layer, for any visible layer lying under an adjustment layer is affected by its adjustment.
Hopefully, and unlike History states, Adjustments layers are saved with the file and can be accessed again when you close and reopen the image.
To create Fill layers go to:
Layer/ New Fill Layer
Or from the Create new fill or adjustment layer icon at the bottom of the layers palette
Are Adjustments and Fill layers Editable?
Yes they are. Just like any other Normal layer, you can always change:
-Their name, by double clicking on their name in Photoshop 7.0 and in Photoshop 6.0 go to Adjustments layer properties to change the name.
-You can also Color code Adjustments layers, and there’s a handy dandy shortcut for doing this, right click on the eye icon in the Layers Palette and chose a color.
-Their Opacity, if you find their effect much too strong.
-Their settings by double clicking on the Adjustments icon in the Layers palette.
-Their Visibility by ticking on/off the Eye icon
-Their stacking order, by dragging them in the layers palette (normally an adjustment layer affect all underneath layers so know where you’re moving it)
- Their blending mode. A lot of interesting tasks/effects could be achieved just by changing the adjustment layer’s blending mode. Say you have a dark image changing the any adjustment layer-blending mode to Screen will do, although levels and curves are greater control, but think of the possibilities.
- You can also duplicate them
- Delete them
- Link them
- Layer set them
Changing Adjustment and Fill layers Content:
You do not have to delete and unwanted adjustment layer to create another. Simply select the adjustment/fill layer or fill layer that you want to change
Choose Layer > Change Layer Content and select a different adjustment layer from the list.
Say you have a levels adjustment layer, you change it to a color balance adjustment layer from: Layer/ Change Layer Content command and chose Color Balance.
Example Technique:
In this example I applied the change layer content command on a Shape layer
Open an image
Make a Shape layer
Go to Layer/ Change Layer Content
Select a new adjustment for the content
See image.
In this example shape layer content changed to an Invert adjustment layer.
Adjustment layers Types:
There are eleven types of adjustment layers similar to those adjustments commands you find under Image/Adjustments, such as:
Levels
Curves
Color Balance
Brightness/Contrast
Hue & Saturation
Selective Color
Channel Mixer
Gradient Map
Invert: “this type of adjustment layer does not have a dialog box”.
Threshold
Posterize
Affecting parts of the image:
Now to limit adjustment or fill layers effect, make a Selection/Closed Path and then apply the Adjustment layer.
Keep in mind that when you apply the adjustment or fill layers against a Selection a Layer Mask will occur.
When you apply the Adjustment or a fill layer against a closed path, a Vector Mask will occur.
Controlling Adjustments Layers
What happen when you apply an Adjustments layer to a layer set?
Which layers will be effected, those only inside the layer set or all below layers?
Well the answers to this could lead to pretty creative thoughts. If you choose a blending mode other than Pass Through for the layer set, none of the adjustment layers or layer-blending modes inside the layer set will apply to layers outside the set. Then if the Layer’s set mode is Pass Through it will show through out the whole underlying visible layers. Keep in mind that the adjustment layer is at the top of stacking order inside the layers set.
Example Technique:
Make multiple layers via copies from the background layer, make different layers
Make a layer set of these layers.
Apply an Adjustment layer inside the layers set.
Now change the layer set blending mode, and you’ll get a variety of effects.
Can an adjustment layers be applied to only one layer?
Definitely. All you have to do is to group it with previous layer, the layer that you wish to limit the adjustment for (a clipping group). Make sure the adjustment layer is right above the desired layer go to Layer/ Group with previous, or, from within the layers palette place the cursor right in-between the two layers hold Alt (Win) Option (Mac).
Basic Techniques with Adjustment Layers:
Colorizing:
Open a Grayscale image
Change its mode to RGB
Select an area in the image
Create a Hue & Saturation adjustment layer
Click the colorize option inside the Hue & Saturation dialog box
Adjust the hue, saturation, and lightness
Click ok.
Advanced Techniques with Adjustments layers:
Retouching Technique:
Lets say you want to whiten the teeth in a portrait shot.
Here is a very fast and sufficient way to do it with a Hue & Saturation Adjustment layer:
Create a Hue & Saturation Adjustment Layer
Reduce the Saturation, to illuminate any color the original teeth might have.
Increase the lightness to brighten up, exaggerate with the brightening, you can control it later by reducing the opacity or by resetting the Hue & Saturation adjustment layer options.
Fill the Adjustment layer’s mask with black, the image looks like untouched
Select a suitable brush
Now paint over the Hue & Saturation Layer mask, paint with white over the teeth, to get them brightened.
If you commit some wrong strokes, paint again wit black this time, as when you work with a Normal layer mask.
What About Fill Layers:
Fill layers allows to quickly adding colors, gradients, patterns to your image without messing with the original data. At the opposite of adjustment layers, fill layers do not affect underlying layers. So to show their effect you have to lower their opacity, or maybe their blending mode.
There are three types of Fill layers:
-Solid Color
-Pattern
-Gradient
Fill layers also comes with a layer mask.
Fill Layers Techniques:
Open an image
Create a pattern fill layer, select the zebra pattern, scale the pattern to taste lower the opacity of this layer to taste
Create another fill layer this time a solid color (choose a color)
Lower the opacity
Create a gradient map adjustment layer, select any gradient that contains transparency
Adjustments/fill layers are so powerful yet so flexible to use. I hope this article gave you something new or was just an inspiration.
Ammar
Adjustment/Fill Layers 
Linear Mode
