As you can see, you can think of layers as transparent sheets placed and stacked on top of each other (Each transparency sheet is a Photoshop layer). Where there is nothing on a layer, you can see through it to the layers below. We use layers to prevent contents of a drawing to mix with each other, to edit them easily, and to organize them. Layers help you editing your artwork on a layer without affecting an artwork on another layer. Each layer may have different objects and elements on it. Current layer is always highlighted in blue color. In the figuration below active layer is Layer 4. We can not work in a layer which is not highlighted. To make a layer "current layer" just click that layer. When it is highlighted you can make any change in it. You can work on only one layer at a time

Generally: Designs, Interfaces, Navigations, and most of all the artwork we see are made up of many basic images that are combined through the use of layers. Each has been started as a photoshop file which is a collection of transparency sheets that are stacked on top of each other. That allows designers to have a freedom in their job and more functionality, so they can edit and change the elements on the layer without changing or affecting the content of the other layers.

For each layer, an opacity setting and a blend mode determine how that layer's content will affect the layers below it such as Overlay, Soft Light, and Hard Light. They all can be used for some special effects. The default option is Normal. Another thing, Layers are named in some way that makes it easy to determine which layers are used for a particular part of the project. The Layers palette in Photoshop provide alot of helpful functions that will help you in your job. You can link two or more layers together to apply the same effect on them, such as scaling, rotating, and moving. Also, you can hide a layer or more temporarily. When working on a number of layers-specially big projects and interfaces-, sometimes it becomes difficult to identify objects in different layers. To avoid this situation we can hide contents of layers.

• Click "Create new layer" button to add a new layer.
• Click "Delete current layer" button to delete a layer. And click "Yes". Or drag the layer to to delete it.
• Click "Eye" to hide a layer or multiple layers. Contents of hidden layer becomes invisible . In the figuration above, Layer 2 is hidden.
• Drag a layer to the "Create new layer" button  to duplicate it. Or right click the layer and choose " Duplicate Layer ".As: Type a name for duplicate layer and click "OK".

Well, now that you understand what Layers are for, you are ready for the other tutorials.