As many Photoshop users, I’ve always overlooked those locking small icons on the top of the Layer panel in Photoshop. I’ve never used it and wondered what is it suitable for. Let have a look at what options do we have on how to lock a layer in Photoshop.

Well, this was my mistake as I could make my work make much more comfortable by using locking layer possibilities. Everybody knows that when you open a file, image, or photo in Photoshop, you get it on to a Background layer. This layer is automatically locked. When I started with Photoshop, it was annoying for me. I always had to unlock the background layer and begin to apply the effect, adjustments, or paint directly on the Background Layer. As I became more advanced, I stopped to use the background layer. I switched to so-called non-destructive editing. Then I realized it is a good idea to have the background layer locked by default.

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Why lock a layer in photoshop
When working with one or two layers in Photoshop, it is quite easy to manage it and have the editing objects under control. But when you to go further, produce more layers, put the partially selected objects on new layers, it could be pretty challenging to see what are you currently editing. You can even occasionally paint on the wrong layer or move unwanted objects. Here the possibility to lock the particular layer becomes very handy. You lock what needs to be locked. You can also be sure you edit only what needed to be edited. The main reason why to lock a layer in Photoshop is to get more control over what is going to be changed or modified. It is very useful in the case of many layers.
Partial Layer Lock
As we already mentioned, when opening a new image in Photoshop, there is a default background layer created, which is locked. It means everything is locked. But there are more options. You can lock only partial parameters of the current layer. For example, to lock only the Transparent Pixels on the Layer. The next option is to lock the Image pixels on the layer. It is practically the opposite of transparent pixels. Another option is to lock the position that prevents you from accidental moving the selected layer.
How to Lock Transparent Pixels on a selected Layer in Photoshop
There are situations when you want to edit only pixels on the selected layer but keep the rest of the layer. In this case, Transparency of the layer to be unaffected. Here you have the possibility to lock the transparency with the very first Lock icon in a row.

After locking, you can paint or apply any effect on this layer. You can be assured the rest of the layer – the transparency – will stay without the impact.
Here we have to mention a substantial point. Locking the layer is always applicable only to the pixel layer. It means if you are working with adjustment layers, the complete or partial locking makes no sense. For example, if you lock the Levels adjustment layer, you can still change the parameters of this Adjustment Layer. So the locking does not work here. Adjustment layers are to be used for non-destructive editing of an image selection or removed background and replaced with a new one.
How to Lock Image Pixels on a specific layer
Another way of how to lock a layer partially in Photoshop is to lock the Image pixels. This approach is complementary to the previous one, where we have locked the transparency. Let’s assume we have a layer with some part of the image or drawing or a layer with artistical characters. And we want to protect this layer from painting on it. Or making other changes in those areas where any pixels are present. We click the locking button with a small paintbrush and Lock the Image pixels on this layer.

If you then try to paint with a brush on that layer, you’ll see it makes any effect only on transparent areas, not on pixels. The same rule is applied when you try to use the Eraser tool or any pixel editing tool, generally speaking.
Locking the Position
In some situations, you want to be sure you never occasionally move the selected pixel layer. In this case, you lock the position by clicking the crossed arrow icon on the layer lock panel.

Now you can select the move tool (V) and try to move the selected layer. You’ll see it is not possible because the position is locked. In most cases, you will start to move the pixels of the layer below your selected layer. It is because Photoshop makes automatically active the layer where you clicked and which is not locked, of course.
Locking Artboards – latest Photoshop version option on how to partially lock a layer
In the latest versions of Photoshop, you cand find the option to lock the Artboard content. There is a small Artboard icon in the layer lock panel.

When you roll over the icon, the following is displayed: “Prevent auto-nesting into and out of Artboards and Frames.” In fact, you can lock the selected artboard and its content by choosing this option.
Lock All
The final option of how to partially lock a layer in Photoshop is the complete layer lock. This is the most obvious option, and you can lock the layer and prevent it from any occasional unwanted editing or moving. In the latest Photoshop versions, you can unlock the layer just by clicking the layer lock icon directly. By clicking the lock again, you lock it again.
How to lock a group of Layers in Photoshop
It is essential to mention you can also lock a group of layers in Photoshop. If you make a new group of layers, you can apply Lock all functionality of the selected Layer group. The second option you can use for grouped layers is the Artboard lock.
Conclusion
As you can see, locking the layer entirely or partially can help you to prevent specific layers of unwanted editing or moving. I want to emphasize again this locking functionality is applicable only on so-called pixel layers in Photoshop. So if you are working with adjustment layers, for example, the locking functionality doesn’t work. For more information, check the Adobe’s help pages.