Thursday 15 September 2011

Photoshop Layers - Introduction

What Would Life Be Like Without Layers?

Before we look at what layers are and how to use them, let's first see what working in Photoshop would be like without layers! We'll start by creating a new document in Photoshop. I'm using Photoshop CS5 here but any recent version will work just fine. Go up to the File menu in the Menu Bar along the top of the screen and choose New:
The File > New command in Photoshop. Image © 2011 Photoshop Essentials.com
Go to File > New.
This opens the New Document dialog box. Enter 800 pixels for the Width of the new document and 600 pixels for the Height. Leave the Resolution value set to 72 pixels/inch. There's no particular reason why we're using this size other than to keep us both on the same page. Finally, make sure the Background Contents option is set to White:
The New Document dialog box in Photoshop. Image © 2011 Photoshop Essentials.com
Set the Width value to 800 pixels and the Height to 600 pixels. Background Contents should be set to White.
When you're done, click OK to close out of the dialog box. Your new white-filled document will appear on the screen:
A new Photoshop document filled with white. Image © 2011 Photoshop Essentials.com
The new document.
Now that we have our new document open and ready to go, let's start drawing on it. We'll keep our "art work" very simple for this example, since we're really just trying to understand layers, not showcase our creative talent. Select the Rectangular Marquee Tool from the top of the Tools panel:
Selecting the Rectangular Marquee Tool in Photoshop. Image © 2011 Photoshop Essentials.com
Select the Rectangular Marquee Tool.
With the Rectangular Marquee Tool selected, click somewhere near the top left corner of your document and drag out a rectangular selection. Don't worry about it's exact size or location:
Drawing a rectangular selection in Photoshop. Image © 2011 Photoshop Essentials.com
Click and drag out a rectangular selection in the top left of the document.
Now that we've dragged out a selection, let's fill that selection with a color. Go up to the Edit menu at the top of the screen and choose Fill:
Selecting the Fill command in Photoshop. Image © 2011 Photoshop Essentials.com
Go to Edit > Fill.
This open's the Fill dialog box. Change the Use option at the top of the dialog box to Color:
The Fill dialog box in Photoshop. Image © 2011 Photoshop Essentials.com
Change the Use option to Color.
As soon as you choose Color, Photoshop will pop open the Color Picker so we can choose the color we want to fill our selection with. You can pick any color you like. I"ll choose red:
Choosing a color from the Color Picker in Photoshop. Image © 2011 Photoshop Essentials.com
Choose a color from the Color Picker. Any color will do.
Once you've chosen a color, click OK to close out of the Color Picker, then click OK to close out of the Fill dialog box. Photoshop fills the selection with your color, which in my case was red:
The selection has been filled with red. Image © 2011 Photoshop Essentials.com
The document after filling the selection with red.
We don't need the selection outline around the rectangle anymore, so deselect it by going up to the Select menu at the top of the screen and choosing Deselect:
Photoshop Select > Deselect command. Image © 2011 Photoshop Essentials.com
Go to Select > Deselect to remove the selection outline from around the rectangle.
So far so good. In fact, that first rectangle turned out so well, we should add a second one! Click inside the document with the Rectangular Marquee Tool and drag out another rectangular selection. Just for fun, start your selection from somewhere over top of the existing rectangle so that the new selection partly overlaps it
Drawing a second rectangular selection in the document. Image © 2011 Photoshop Essentials.com
Make sure the new selection partly overlaps the original rectangle.
With the second selection added, go back up to the Edit menu and choose Fill so we can fill it with a color. The Use option at the top of the dialog box should already be set to Color, but if you simply click OK to close out of the dialog box, Photoshop will fill the selection with the same color you chose last time, and that's not what we want. We want a different color for this second rectangle, so click on the word Color, then re-select Color from the list of options (I know, it seems weird), at which point Photoshop will re-open the Color Picker. Choose a different color this time. I'll choose green. Again, feel free to pick any color you like as long as it's something different:
Choosing green from the Color Picker in Photoshop. Image © 2011 Photoshop Essentials.com
Choose a different color for the second rectangle.
Click OK to close out of the Color Picker, then click OK to close out of the Fill dialog box. Photoshop fills the second selection with your chosen color. To remove the selection outline from around the second rectangle, go up to the Select menu at the top of the screen and choose Deselect, just as we did last time. We now have two rectangles, each a different color, in the document. Award winning stuff:
Two rectangles, each a different color, in the document. Image © 2011 Photoshop Essentials.com
I call this piece "Two rectangles, two colors, one document."
If that isn't a work of artistic genius, I don't know what is. Although.... hmmm........
Now that I've been looking at it for a while, I'm not sure I'm happy with something. See how the green rectangle overlaps the red one? I know I did that on purpose, but I think it was a mistake. It might look better if I swapped them so that the red rectangle was overlapping the green one. Yeah, that's the problem. The red shape needs to be in front of the green shape. Then my masterpiece will be complete! All I need to do here is grab the red one and move it over top of the green one.
We do that by..... um.... hmm. Wait a minute, how do we do that? I think we have a problem here. I drew the red one, then I drew the green one, and now I just need to move the red one in front of the green one. Sounds simple enough, but how? The simple answer is, I can't. There's no way to move that red shape in front of the green one because the green one isn't really in front of the red one at all. It's just an illusion. In fact, the two rectangles are not really two rectangles, at least not as separate independent objects. Again, It's an illusion. The green shape is simply cutting into the red one, and the pixels that were initially red in the original rectangle were changed to green when I filled the second selection.
Speaking of illusions, the two rectangles are not really sitting in front of the white background, either. The entire thing is nothing more than a single, flat, two-dimensional image. Everything in the document - the red shape, the green shape and the white background - is essentially stuck together. We can't move anything without moving everything.
Let's take a quick look in our Layers panel to see what's happening. Notice that everything - the two rectangles and the white background - is sitting on a single layer. This means everything is part of the same flat image:
The Background layer in the Layers panel in Photoshop. Image © 2011 Photoshop Essentials.com
The Layers panel showing everything on the Background layer.
With all of our work on a single layer, we don't have many options if we want to change something. We could undo our way back through the steps to get to the point where we can make our change, or we could scrap the whole thing and start over again. Neither one of those options sounds very appealing to me. There must be a better way to work, one that will give us the freedom and flexibility to make simple changes like this without having to undo and redo anything or start over from scratch.
Fortunately, there is. Let's try the same thing, but this time using layers!

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