Let me start by telling you that before Photoshop CS2 was introduced Layer Groups were called Layer Sets. The tutorial was written before Photoshop CS2 was released, so some of the screenshots are still based on Photoshop CS and you will read "Layer Set" in some of those.

Layer Groups are a great way to get your layers organized. The following image contains about 115 layers. Most of these layers however are hidden inside 11 Layer Groups . This has several advantages and some of which might not all be that obvious. For one thing it makes it easier to get things organized. Your layers palette will look less cluttered and there will be less need to scroll. But above all there are several interesting things you can do with layer groups. The more and more you use layer groups, the less you use linked layers.

You create a new Layer Group by clicking on the Layer Group icon at the bottom of your layers palette. It's important that you name your layer groups, otherwise you will get confused when you have a few of them.

In Photoshop CS2 you can select multiple layers (or a single one) and press Ctrl + G (Command + G on the Mac) to group them or you can drag and drop the layers on the Create a new group icon :

A layer group allows you to turn off several layers all at once. The candle on the left is made out of 7 layers. To make the candle invisible, you just need to make the layer invisible (1 , bottom left, in front of the bowl).

It's easy to move layer groups. To move the candle on the right to a different spot, I just need to activate the layer that contains the candle and then I can use the move tool to move the candle to the background (2).
You might want to move the candle in front of the pumpkin, in that case your layer group with the candle will be higher in the layers palette than the the pumpkin layer group. It's the other way around if you want to move the candle behind the pumpkin.

It's easy to duplicate objects by dragging and dropping a layer group on the New Layer icon at the bottom of the layers palette. In this example I dragged the left candle layer and dropped it on the New Layer icon (3) and as a result a new layer was created with the name left candle copy. In this example I moved the layer group that contains the copy to the right using the Move Tool , so that you can see that I now have two identical candles.

You can add a layer mask to mask parts of a layer group. In this example I've masked the stand of the candle (4).

You'll probably know that you can change the opacity of a layer. You can however also change the opacity of a layer group once activate it. This will change the opacity of the complete layer group.

A layer group has its own blending mode. By default the blending mode is Pass Through (6). This means that all the adjustment layers or layer blending modes inside the layer group will affect all layers below and outside the group.
In our example the green circle turned into olive. Once we change the blending mode to anything different than Pass Through, in our example Normal, then we see how the Hue & Saturation adjustment only effects the layers inside the layer group; the yellow square turned into olive, but the square kept its green color.

You can also lock complete layer groups. Once you lock a layer group, all layers inside the layer group will be locked too (7).
This will also lock the layer group's opacity as you can see in this example.

Photoshop CS introduced nested layer groups, which means that you can have a layer group inside a layer group.
You can drag & drop a layer group on a another layer group or you can create a new one inside an existing group.

You can click on the little triangle in the layers palette (5) to view a menu that has all kind layer groups related options that you can use.

 

Comments
New Group From Linked Layer Group properties Merge Layer Group	: create a new layer group and moves all linked layers into this new group : turn on/off specific channels or color your layer group inside the layers palette : this merges all layers of any kind inside the layer group to a single layer.

Some people ignore the power of layer groups, thinking that it just about grouping layers and that's about it. You've learned by now that grouping layers is just part of the power of layer groups. It's what you can do with them what makes them really useful.
It's not always necessary to use layer groups, but once you're scrolling through 100 layers, you might consider to use them!

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