Merging layers in Adobe Photoshop is a necessary, sometimes life-saving technical operation that allows you to get rid of unnecessary confusion and "garbage" in those moments when a volumetric composition threatens to grow like a snowball.
Instructions
Step 1
The division of information into many layers that make up the composition is, on the one hand, a very convenient help in the work - each separate layer can be processed and changed independently of the others, on the other hand, this division sometimes interferes with performing just the same operations for all layers or simultaneous applying filters.
Therefore, in order not to deprive yourself of freedom, you must always be aware of whether you really need to merge the layers together, or it is enough to just virtually "link" them for the possibility of a single transformation, or even just simply group and sort them into "daddies" so as not to get confused in the wilds of the composition.
If you need to simultaneously move, reduce, rotate, reflect, or some other kind of geometric transformation of several layers - for example, each of them has one of the parts of a large object, and the entire object needs to be moved or reduced - this can be done without any damage to their individual content.
Select several layers in the list of layers that you need by clicking on the lines with the names of the layers, while holding down the Ctrl or Shift key, in accordance with the standard rules for selecting elements adopted in the OS interface. When several layers are selected in the list, click at the bottom of the list on the icon with the shown chain links. (You can also do this through the menu Layer> Link Layers) Now the layers have become linked for a general transformation: by shifting one, you will shift all associated with it, when you scale one, the rest will stretch, etc. You can pay attention to the fact that now, when you select one layer, at the end of the lines with the layers connected to it, chain icons will be highlighted. Accordingly, you can break the link between layers by clicking on the icon at the bottom of the list of layers. If at the same time not all layers are selected, then only the selected ones will be excluded from the list of connected ones, the rest will remain connected with each other.
Step 2
You can combine layers in a different way by enclosing them in a single group. Layer groups in Adobe Photoshop are the prototype of the nested folder structure used in computer systems. Layers can be combined into a folder, folders, in turn, nested in others, etc. There are several advantages to such a combination:
Firstly, it creates order in the list of layers - the unnecessary contents of the folders-groups can be visually collapsed so that they do not interfere with the overview, this, of course, will have a positive effect on the convenience and speed of finding the necessary objects in the list.
Second, the layer group has common blend mode and transparency options. Thus, for example, there is no need to make each layer semitransparent, setting the corresponding parameters each time the same for such layers - you can once collect them into one group and set the total number.
Thirdly, moving and transforming objects combined into a group is as easy as "linked" through Link Layers, but the new way of linking is more flexible and convenient. If you select a group header in the list of layers, the transformation performed will affect all layers in it. But if there and then the need arises, for example, to individually move any separate layer, this can be done simply by purposefully selecting it in the list, without additional procedures - let me remind you that in linked layers it would be necessary to first "unhook" it from the list, and then re-list.
Fourthly, the group has a common transparency mask, so when merging layers into such a folder, there is no need to control the outlines of each separate layer - the excess can be "cut" with a common mask.
It is not difficult to create a group folder: to do this, you need to click the corresponding icon at the bottom of the layers panel, or go through the Layer> Group Layers menu. You can include layers in a group by dragging and dropping them in the list onto the group's header, or extract them, respectively, by moving them out of the group.
Step 3
In the latest versions of the Adobe Photoshop program, there is one more merge mode - the creation of a so-called Smart Object from several layers. This is essentially the inclusion in one document of another independent one, which opens in a separate window and can be edited and saved, after which the results of these operations will be displayed in the main document. A big plus of this method of merging layers is that you can connect the Filter Gallery property to the Smart Object, that is, thus apply a single filter to several layers at once, and the content of these layers remains intact, while you can modify the parameters themselves filters, achieving the best result, and, if necessary, make changes to the layers themselves, their relative position, the mode of inclusion in the composition, etc.
Step 4
If the previous methods of merging layers do not suit you, for example, for purely economic reasons - no editing of layers is definitely implied, all complex filters have already been applied and configured, the relative position of layers will not change in any way, so there is no reason to have a battery of separate layers that takes away program resources and disk space - you can simply merge them together, make one simple layer out of them.
To do this, select the layers we need in the list of layers, and in the context menu we find the item Merge Layers, you can also do this through the main menu command Layer> Merge Layers or by pressing Ctrl + E on the keyboard.
To facilitate this operation, you can also select the Merge Visible operation located next to the menu, then you do not need to select anything in the list of layers - everything that is currently displayed in the viewport will merge into a single layer.
You can also merge layers that were previously collected into one group - in the context menu, select the item Merge Group. Of course, the group will then cease to exist, and a new layer will appear in its place.
Step 5
Finally, you can apply the most radical method - choose the Flatten Image command from the menu. Then all information about the layers will be completely lost: everything that was in the composition will be replaced with one base layer, which, moreover, will be the background layer - i.e. everything that went beyond the canvas will be cut off and disappear. In practice, it is very rare to resort to such a step, because no one is immune from error, and re-doing the work on recreating and separating layers is an extremely ungrateful task, moreover, sometimes technically impossible. Sometimes, inexperienced users believe that the implementation of Flatten Image is necessary in order to have a complete final image that can be sent to friends or customers, posted on the Internet, etc. This is not true. The composition file simply needs to be saved in two different formats. One is a complete document with the possibility of further editing and correction in the "native" format of the Adobe Photoshop program (menu File> Save or File> Save As) And another file is just for Internet needs, for example, in the popular JPEG format, you can save additionally (for example, through the File> Save for Web menu, which has all the necessary settings for optimal image saving specifically for transmission over communication channels), while no special merging is needed - everything will be saved in one picture automatically. So you will always be insured against the need to do additional repetitive work and bitterly regret the lost information, opportunities and time.
