Flattening and saving files
When you finish editing all the layers in your image, you can merge or flatten layers to reduce the file size. Flattening combines all the layers into a single background layer. However, you cannot edit layers once you’ve flattened them, so you shouldn’t flatten an image until you are certain that you’re satisfied with all your design decisions. Rather than flattening your original PSD files, it’s a good idea to save a copy of the file with its layers intact, in case you need to edit a layer later.
To appreciate what flattening does, notice the two numbers for the file size in the status bar at the bottom of the document window. The first number represents what the file size would be if you flattened the image. The second number represents the file size without flattening. This lesson file, if flattened, would be 2–3MB, but the current file is much larger. So flattening is well worth it in this case.
Select any tool but the Type tool (), to be sure that you’re not in text-editing mode. Then choose File > Save (if it is available) to be sure that all your changes have been saved in the file.
Choose Image > Duplicate.
In the Duplicate Image dialog box, name the file 04Flat.psd, and click OK.
Leave the 04Flat.psd file open, but close the 04Working.psd file.
Choose Flatten Image from the Layers panel menu.
Only one layer, named Background, remains in the Layers panel.
Choose File > Save. Even though you chose Save rather than Save As, the Save As dialog box appears, because this document has not yet been saved to storage.
Make sure the location is the Lessons/Lesson04 folder, and then click Save to accept the default settings and save the flattened file.
You have saved two versions of the file: a one-layer, flattened copy as well as the original file, in which all the layers remain intact.
You’ve created a colorful, attractive postcard. This lesson only begins to explore the vast possibilities and the flexibility you gain when you master the art of using Photoshop layers. You’ll get more experience and try out different techniques for layers in almost every chapter as you move forward in this book.