You can “buy” a copy of the class notes for this workshop from the red box.
Lyne Mayflower who has been teaching these introductory classes on photo editing is not able to be here today. Rather than just skip the week, I thought this would be a good time to focus specifically on layers.
Over the last few weeks, Lyne has shown you some basic techniques that involve the use of layers. However, she kind of snuck the whole topic in by the back door. She got you using layers but never really talked that much about what they are.
She and I talked last night and felt there was still some confusion about layers that deserved more attention. Today, I’ll talk more about layers, and try to get you to use them more. This would be a good opportunity to ask any questions you may have about them as we go along.
Unfortunately, I’m not as conversant with as many photo editors as Lyne is. I use Photoshop CS4 and can get by in Gimp. If some of you are using other photo editors, I won’t be able to help you. I’m fairly confident you’ll be able to follow along with this workshop though since the concepts a pretty general and the will be found in all editors, although perhaps with different names.
Perhaps those of you with other editors can help each other out via IM.
All Paintshop users please announce who you are.
All Photoshop Element users please announce who you are.
Anyone else using other photo editors?
Take note of those using the same editor as you. If you get lost with a tool or feature that is specific to your editor, IM someone else in your group.
Ok, let’s get started. The point of this workshop to give you a solid basic introduction to layers. Layers serve as the basis for any serious photo editing work. It’s not unusual for a master photo editor to end up with dozens of layers in any given project.
Think of layers as drawing on a stack of clear plastic sheets. You draw a different aspect of the whole scene on different sheets then you stack them up and look at them.
Obviously, top layers cover what may be drawn on layers below. So the order of the layers determines what you will see in the final product.
Photo editors allow you do do things with layers that would be difficult or impossible to do with real plastic sheets. You can set the opacity of a layer to determine how much the layer actually covers the layers below.
You can also determine how the top layer interacts with layers below. These are the so called blend modes. Lyne introduced the overlay blend mode last week. We’ll talk more about all this later.
Let’s start by opening up your photo editor. In Photoshop you have one window from which you work. In Gimp, you have 2 windows. The main one, usually on the left contains they actual image. The Toolbox window contains all the tools.
From the menu at the top of the main window select File → New to start a new project. Photoshop asks you to name it. Gimp will ask for a name when you go to save it later.
Then you have to specify the image size. In SL we usually specify the size in pixels. Remember, the maximum size of a photo or texture in SL is 1024×1024. It’s best to keep the size in powers of 2, (i.e. 64, 128, 256, 512, 1024).
Think about the aspect ratio (ratio of width to height) that the texture will be applied to and make the size of your project the same, keeping at least one of the dimensions (usually width) in a power of 2.
Finally you have to specify what that layer should be filled with (Fill With in Gimp, Background Contents in Photoshop). Notice the little down arrow to the right of the box will bring up a drop down box from which you can select an option. Usually the first (background layer is filled with a color determined by what your default foreground and background colors are. If you select transparent, you will get a layer filled with a white and gray checkerboard pattern.
You can change the color by clicking on the toolbox icon that looks like two screens overlaying each other (usually white and black to start with).
Go ahead a select a color for your first (background) layer and click ok.
The window that allows you to manipulate your layers is at the bottom right of your screen in Photoshop and at the bottom of the Toolbox window in Gimp.
Notice a new layer has been created and called Background. It is a special layer that will always remain at the bottom of the stack.
Notice the tabs above that newly created layer. In Photoshop you want to make sure you have the Layers tab active. In Gimp it’s the tab that looks like a stack a white paper.
You can change the color of this layer by using the Bucket Fill Tool in Gimp or the Paint Bucket tool in Photoshop. Both look like paint cans and will fill the layer with the foreground color.
Are there any questions about what I’ve covered so far?
Ok let’s add 3 more layers on top of the background layer. Usually when you add layers you make them transparent.
Notice the row of icons at the bottom of the layers panel. If you hover your mouse over them, hover text will appear telling you the name of the icon. The icon to create a new layer is in that row. In Photoshop it’s called Create New Layer and is the second from the right. In Gimp, it has a similar name and is at the far left.
You could also do the same with Ctrl-Shift-N or from the top menu of the main window by clicking on Layer → New (Layer). In Gimp you can also right click on a layer and select New Layer from the context menu.
Go ahead and create 3 new transparent layers. Each time you do the program will ask you to name the layer. It’s a good idea to name it for what that layer will contain. In this case call them Square, Circle and Rectangle.
What you should end up with are the following layers from top to bottom: Rectangle, Circle, Square, Background.
At any time, only one layer is the active layer on which you will work. It is highlighted in the layers panel. If you’re not getting the effect you expect when using a tool, make sure you have the correct layer highlighted. It’s a common mistake to be working on the wrong layer.
You can rename a layer by double clicking on the name of the layer. You can move layers around by left clicking on the layer and dragging it up or down. Notice the background layer can’t be moved in Photoshop.
Any questions about creating new layers?
Next I want you to draw a simple, square, circle and rectangle on their respective layers. Highlight the “Square” layer. In Photoshop, select the Rectangular Marquee tool, second from the top. In Gimp, select the Rectangle Select tool, top left if the Toolbox window.
Go over to your main window showing the picture, left click somewhere and drag the mouse diagonally from there. You start drawing a rectangle. When you get it close to looking like a square, release the mouse button. (In photoshop you can hold down the shift key to force it to be a perfect square.)
Notice you end up with a square defined by moving dotted lines. These are referred to as marchind ants and define a selected area of your picture.
While you see the marching ants, go over to your paint bucket tool, select a color and click inside the square to fill it with the new color. Remember to select your desired foreground color before clicking inside the square.
Finally deselect the marching ants. Photoshop: Ctrl-Sift-D, Gimp: Ctrl-Shift-A. You can also do this From the top Select → Deselect menu option.
So now we have created our square on its own layer.
Any questions about this?
Next I want you to draw a circle and a rectangle on their respective layers. Make each of them a different color and offset them from each other so they are all somewhat visible.
The circle is created by using the Elliptical Marquee tool in Photoshop or the Ellipse Select tool in Gimp. In Gimp, it’s to the right of the Rectangle Select tool. In Photoshop you have to click on the Rectangular Marquee tool and hold to bring up the other tools under it. Select the Elliptical Marquee tool.
As above, click and drag. In Gimp you have to eyeball it or look at the dimensions of the selection in the bottom left of the main window to know when you get a circle. In Photoshop, hold down the shift key as you draw.
Do the same for the rectangle.
I’ll wait for you to finish doing that and take any questions as you work.
Is everyone pretty much done with that?
Now let’s play with our layers.
Notice the little eyeball icon to the left of each layer in the layers panel. Clicking these on or off will make that layer visible or invisible. Use this to look at just those layers you want to see while you’re drawing on that layer. (Obviously, if a layer is invisible, you can’t draw on it.
Another good use for making various layers visible or invisible is if you have a project in which you’re making several version of a sign or picture that vary slightly in what they show. Put the varying parts on different layers, show the ones you want to see in a particular version and save each version as a png file to be separately uploaded to SL. This allows you to use one project for all the versions.
Try moving a layer up and down the stack and notice how top layers cover those below.
If you don’t like where you drew a figure you can move that layer around within the image window by using the Move tool. In Photoshop it’s the topmost tool in your tool panel. In Gimp, it’s in the middle of the tool box and looks like horizontal and vertical lines with arrows. Try moving a layer around like that now. Remember to select the layer first before moving.
Next change the opacity of a layer. The opacity controls are at the top of the layers panel. In Gimp it’s a slider labeled Opacity. In Photoshop there’s a box to the right of the work “Opacity” with a right pointing arrow to the right of it. Click on the arrow to bring up the slider.
Play around with the opacity sliders of the different layers.
Finally, let’s play with blend modes.
Remember, a layer’s blend mode determines how the this layer will blend with the layers below it. Gimp has 21 different blend modes. Photoshop has 25. I won’t go into exactly what each blend mode does but will let you read about it on your own.
If you Google Photoshop Blend Modes or Gimp Blend Modes you’ll come up with a bunch of sites that explain what the various blend modes do.
One I found for Photoshop is http://www.myinkblog.com/2009/07/14/an-explanation-of-photoshop-blend-modes/
For now you can experiment with changing the blend modes of different layers to see what effect it will have.
Blend modes provide a very powerful set of tools for producing all sorts of interesting effects. You can read more about this on your own by pursuing various tutorials.
Any questions about any of this?
Ok that’s all we’ll do today. I hope this has given you a better understanding of layers.