Important Layer Information

Photoshop 6.0 does not have the 100 layer limitation. In fact, you can have a maximum of 8000 layers (including layer sets and layer effects). However, this is further limited by the amount of memory in your system.

In Photoshop 5.x layers are only preserved when you save the image to Photoshop's native PSD format. In Photoshop 6.0 and up, layers are preserved when you save to PSD or TIFF format. (In Photoshop 6.0, you must enable "advanced TIFF options" in preferences before you can save layers in TIFF format. In 7.0 and up, you are not required to change preferences.)

When working on layered images, it is always a good idea to save a working copy of your layered file in the native Photoshop format for future editing purposes. To reduce the image file size and for compatibility you will usually need to export a second copy of the file to an alternate format determined by the intended use.

In Photoshop 5.x, when you want to save a layered file in a format other than PSD, you will need to use the Save a Copy or Save for Web command. When you do this the image will be flattened, meaning that all layer information will be merged into a single background image and any hidden layers and will be discarded.

In Photoshop 6.x, you can use the Save As command and the image will be flattened automatically when you choose a format other than Photoshop PSD or Photoshop PDF. A warning will appear to alert you that some image data will be lost when using a format that does not support layers.

While more and more graphics programs are adding support for the Photoshop (PSD) format, it's important to know that most of these programs do not support all of Photoshop's layer features such as layer effects, layer masks, and adjustment layers. Before porting layered Photoshop files to other programs, it's best to simplify layers as much as possible. You do this by flattening the file manually or by merging layers together. We'll learn more about how to do this in the coming lessons.

It's also important to know that an image's color mode can affect the way layers interact with each other. For this reason, any time you convert a Photoshop document from one color mode to another, you will be prompted to flatten the file first. You may continue without flattening, but be aware that your results could change drastically depending on what layer effects and blending modes you may have used. Of course, if you don't like the results you can always undo the conversion and flatten your image before changing modes again.

That about covers the basics of layers and the layer palette. In the next installment, we'll get into some actual layer manipulation and explore additional layer functions in the layer menu. In the mean time, you may post your layer questions in the interactive classroom.