The first part of this book focuses on mastering core tools: layers, selections, masks, and colorspaces. The second part builds on the first by presenting an in-depth treatment of touchup, enhancement, compositing, rendering, and image creation for the web. The following gives a synopsis of what you will find in each chapter.
Chapter 1 reviews the GIMP basics. It introduces the GIMP dialogs, reviews window features, and explains a host of functions that are basic but should not be taken for granted. An experienced GIMP user could quickly flip through this chapter of the book, especially if he or she's already familiar with the main features of version 1.2.
Chapter 2 covers layers. Layers are the fundamental building blocks of the GIMP. They are the image unit that plays the most important role in our work, and it is important to understand them and the functions that manipulate them. Even if you are already familiar with layers, this chapter will be worth reviewing because it contains many insights into how to use layers efficiently and effectively.
Chapters 3 and 4 give a unified and in-depth presentation of selections and masks. To the casual observer selections and masks may seem like very different animals. However, they are really complementary implementations of the same thing. The goal of both is to isolate a part of an image. Selections do this by selecting a group of pixels in the image, and masks do it by masking some pixels, leaving the rest exposed. Thus, selections are masks, and masks are selections. These two chapters explain how selections and masks can be made to work efficiently and effectively together.
Because selections are often the most time-consuming part of any project, Chapter 3 compares the different selection tools and describes the applications for which each is best suited. Chapter 4 makes the conceptual link from selections to masks. This chapter describes a host of advanced mask techniques, including methods for refining selection edges and a super technique for finding natural masks you won't want to miss.
Chapter 5 adds the final component of our basic skill set by describing colorspaces and the tools used to get results with color. The first half of this chapter is conceptual, covering RGB and HSV colorspaces. The second half covers the GIMP's blending modes. These are often poorly understood and under-utilized by beginning users. As will be seen in later chapters, the blending modes are valuable tools, without which many needed operations would be quite impossible. The material covered in this chapter is critical for color correction, compositing, rendering, and web graphics... the entire second half of the book! The chapter's intuitive approach explains the aspects of color theory you'll need for your GIMP projects.
Chapter 6 presents techniques for photo touchup and enhancement. The main feature of this chapter is the use of Curves, a poorly understood but amazingly powerful tool. I think that the material covered in this chapter alone is worth the price of the book. In addition to the use of Curves, this chapter also covers the use of the Clone tool for the elimination of blemishes and the use of a sharpening filter, oddly named Unsharp Mask.
One of the most interesting, fun, and useful uses of the GIMP is compositing. Compositing is collage, photo montage, and all the techniques that go with these. Compositing is probably the premiere use of an image manipulation program such as the GIMP, and Chapter 7 covers this topic in detail. This chapter more than any other depends on using the methods and techniques presented in the earlier chapters and is strongly oriented around project work. The projects show how to effectively use selections, masks, and color correction techniques, among other tools, to achieve terrific compositing results.
Chapter 8 describes the tools and techniques for creating shadows, punchouts, and bevels. In addition, it gives an in-depth description of the Emboss and Bump map filters. These are powerful tools for creating 3D effects in images
Chapter 9 is the final chapter of this book. It covers some of the most useful features in the GIMP for Internet web applications. This chapter describes tools for creating animated GIFs and clickable image maps. It also covers several other topics that are required reading for anyone creating graphics for the web.