This page explains what the Layers in Photoshop are all about, using the Robin (Sojourner) Wood T-Shirt for Second Life as an example. If you know about Layers already, and just want detailed instructions for using the template, click here. If you want to download the file discussed, so you can follow along, click here.
This is the Layers Palette. It might be grouped with the Channels palette in your copy of Photoshop, but that's not important. For now, we're just looking at this one thing. If you can't find it, go to Window > Layers, or tap F7 on your keyboard to bring it to the front of the interface.
Layers are something like sheets of clear acetate, stacked on top of each other. Any painted area (opaque pixels) on one layer will cover whatever is below it on lower layers. Semi-transparent pixels will allow some of what is below them to show, and completely transparent pixels will allow what is below to show as if there was nothing above it (mostly because there's not.)
Layers aren't exactly like clear sheets, though, because you can change how they interact with the layers below them, using Blending Modes. Most of the layers in this file use the Normal blending mode, (the one that behaves the way you'd expect clear sheets to behave.) There are two exceptions, and we'll discuss them in the main tutorial, when we get to them..
For now, let's just take a look at the palette. (These screen shots are from Photoshop CS2. If you're using a different version, your palette might not look exactly like this. But all the things we'll be discussing will be there.)
Each section of the palette shows a Layer, stacked one of top of the other, just as if you were looking at a cross-section of that pile of clear sheets with stuff painted on them. Each Layer also has a number of things, that allow you to manipulate that layer.
Lets look at an enlarged version of a single layer. Starting from the left, there's an eye icon, which tells you that the layer is visible.
Any layers that don't have this icon are Hidden. They are still there, but they don't affect the image that you see on your screen in any way. (They will have an empty "well" where the icon should be, instead, so you know exactly where to click if you want to toggle the visiblity to "on".)
To hide a layer, or make it visible, just click on that icon. Try it now.
If you click directly on the eye in the "Design Example" layer, you'll notice that the image of the harp vanishes. If you click again, it comes back. Simple as anything!
Next, you'll see a Thumbnail image of whatever is on that layer. (There may be several things between the eye and the Thumbnail, depeinding on your version. Ignore them for now.) This will show you what's on the layer. If you have a checkerboard pattern set in your Preferences > Transparency & Gamut dialog, you'll see the choosen checkerboard where ever the layer is transparent. In the screenshot here, I've chosen a blue and white checkerboard pattern.
Sometimes, it's difficult to see things against the checkerboard, so never assume that a layer is blank if you don't see something in the thumbnail. For instance, the Highlights and UVs layers both appear blank - but neither of them is.
If you have a Text layer, or another special kind of layer, you'll see that in place of (or attached to) the Layer Thumbnail image. For instance, the T in the "Visit http://.. " layer shows you that the layer contains editable text.
Next you'll see the name of the layer. You can double click on the name to change it. I highly recommend that you name layers, since it makes it much easier to remember what is where, especially if it's been several months since you looked at a file.
Layers are automatically named sequentially (Layer 1, Layer 2, etc.) if you don't change the name.
Special layers have special names. For instance, an Editable Text Layer uses the text itself as the Name. (You can change it, but I don't recommend that.) Adjustment and Fill layers will use the type of Adjustment of Fill as their Name. (However, those layers are beyond the scope of this tutorial.)
Finally, if you are using Layer Styles, you'll see an icon at the right of the layer that shows you that you are. You can edit the Layer Styles by double clicking on that icon, or see which sorts of styles you are using by clicking on the arrow in CS2.
Okay, now that you understand what you're looking at, return to the main tutorial, and let's start to put your picture on the shirt!
This page is just one part of a longer tutorial. Feel free to print it out, or use it for yourself without restrictions. However, if you want to include it in coursework, or put it on a disk, or distribute it in any way, please write to me and ask for permission.