This is the second part of our tutorial series on Photoshop layers. In this article, we will be delving on the important aspects related to adjustment layers and merging layers.

Adjustment Layers

Throughout this Photoshop tutorial series, we will be dealing with various exposure and color adjustment methods. These Photoshop tools are accessed and used as an adjustment layer. Most of the available image adjustments at Image/Adjustments/ can also be accessed as adjustment layers.

These adjustments are potent tools of Photoshop, and when you use them, you are actually making permanent or irreversible changes to the image. For instance, you are actually suppressing the green component of the image when you integrate Magenta into the image. Once the change has been executed, the old information is completely gone, and this is replaced by the new information that was interpolated.

In the event that you want to revert back to the original state of the image, you can only do this if you interpolate it back. Interpolation refers to the application (in this article, it is Photoshop) that is used to mathematically contract or compress the image’s old information, and designate the values for the new image.

Every time an interpolation happens, the information comes off with lesser quality, and after several generations, you will end up with an image of poorer quality.

So, what would be the ideal workaround to this limitation? It would obviously be adjustment layers. With adjustment layers, you can achieve the same thing as in the normal image adjustment. However, you are actually “separating” those changes from the original image so that you are in effect not altering any information on the original image.

You can achieve this when you create a new layer mask which is attached to the adjustments.

To access any of the adjustment layers, you either select the icon for the adjustment layer from the Layers Palette or proceed to the Layer/New Adjustment Layer/ and choose one. Whatever adjustment you pick, this will be displayed as a control panel which can be adjusted anytime, and once it is applied, it automatically becomes an additional layer.

One of the great things about adjustment layers is that such function somewhat “saves” the adjustments that you make. The practice in the past was to make notes about the adjustments made on the color balance or saturation in obtaining the desired result. This tedious process is no longer required. The adjustment layer will no longer revert back to the zero values and it remains the same and retains the last information that has been applied. You also have the option of reopening and making further adjustments on them anytime you find the need for them. This can be accomplished by simply clicking the icon for adjustment.

BONUS Tip – Since the adjustment layers are in effect “juxtaposed” with a layer mask, one where everything is revealed, you can perform “selective” erasing on the applications of the subject adjustment in specific sections of the image. You can do this by painting on the layer mask that is attached every time you don’t want to access and use the adjustment application.

You also have the option of applying black paint with varying opacities, and when you do this, you are actually reducing the opacity of your adjustment layer in that section or part of the image.

Merging Layers

If you know very little or none at all about merging layers, then this section of our Photoshop tutorial series is a must read.

Background Setting – The unlocking of the background is considered as one of the most important steps. You have to remember that you will not be able to move the background if it is not redefined as a layer. The background unlocking can be achieved by simply double-clicking it. You have the option of retaining its designation as background, although the default name for Photoshop for this purpose is “layer 0.”

Once you redefine as a layer your default background, you not only get the option of setting layers below it but achieve transparency of such layers as well. Typically, if you have a background and want to erase it or increase the size of the canvas, what will be displayed is the color of the background displayed on the color palette, whatever that color is. This information may not appear to be relevant to merging, but a clear understanding on how to redefine the background can save you from getting into all sorts of troubles when merging layers.

Merging Down – There are situations where you will find the need to combine or merge 2 layers into a composite single layer so that any adjustments that you make which are not considered layer adjustments will be applied to the 2 layers that have been combined or merged.

Important REMINDER- The merging down of layers is irreversible and the two layers are inseparably connected.

If you need to create a new layer where you can toy around with various design ideas and concepts while maintaining the original layers, then you need to learn how to work with Merging Visible.

Another instance where you will need to merge layers is when you want to set a style or an item that is vector-based. Vector-based items include type as well as shapes that are drawn using Photoshop. These items are made of vectors, and these are rasterized only when one is not working on the layers. A vector image is the opposite of a bitmap or rasterized image. Thus, some of the Photoshop tools cannot be used effectively on it. In such a case, a new layer can be created which is a transparent layer by default.

The Merge Down function can be accessed through Layer/Merge Down or by clicking the arrow symbol found on the Layer Palette’s upper right hand corner.

Merging Visible – A simple Merge Visible will not have separate layers, and as the term implies, this function merges all visible layers into a single layer, which is also inseparable. Merge Visible is found in the same place where the Merge Down is located. It can also be activated through the following keyboard commands:

•    For Mac users – command-shift-E
•    For PC users – CTRL-shift-E

Important Reminder – Option-clicking (for Mac users) or Alt-clicking (for PC users) on the “eyecon” of the layer will automatically hide the other layers, and when you repeat the same action, the hidden layer is shown again. This keyboard command is useful in case you want to merge some of the involved layers while hiding the majority of the layers in an instant. It may be helpful if you are able to see how far you have gone in your adjustments when you have several layers over your background image.

Advanced Merge Visible – This is definitely the best way to do the merging of layers. This technique will allow you to make a new layer derived from all the other layers that are visible and over the background image.

You can merge all the layers that are visible into a single layer, but this procedure will result to the loss of the layer’s solidarity. A better alternative would be the creation of a new layer, which is transparent and blank by default.

To copy the other layers and merge the information of the layers onto the newly created layer, you select the new layer and on the top of the layer stack, press the option (for Mac users) or alt key (for PC users), while the Merge Visible is selected.

In most instances, this newly created layer is placed on the top of the layer stack. This should be the case when adjustment layers are involved. The main reason for this is that the visible layers, which include the adjustment layers, if there are any, are merged or combined with the new layer without losing their respective information. In case you create this new layer and it is not placed over the adjustment layer, then this newly created and merged layer will be receiving the same set of information on the visible layers twice.

Once you have this newly created and merged layer, you are able to make the required adjustments to all the merged layers instantly. You may also copy the layer and such action will also automatically copy all the layers without flattening. SB