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At this point, you should have a basic understanding of the GIMP’s windows, menus, and preferences. You’ve seen how to combine two images in a simple GIMP project, and perhaps you’ve spent some time playing with some of the GIMP’s built-in filters and plug-ins. Now let’s move on to the details of image editing and explore how to make digital photographs look better.

Now you know enough to take your photos, fix any minor problems they may have, and share them with anyone in an appropriate size and format. You can crop your photos to preserve the most important parts and get rid of the rest. You can correct problems with brightness and contrast, minor rotation difficulties, and red-eye caused by too much flash. You know when to use GIF, when to use JPG, and when to use PNG or TIFF. You can even modify photographs that aren’t completely in focus. That may be enough to keep you busy for quite a while.

But there’s so much more that you can do with an image-editing program! The heart of image editing is learning to use layers. It’s a different model than you may have used in simpler photo-editing programs, but once you begin to use layers, you’ll wonder how you ever lived without them.

So take a deep breath, and prepare to explore layers, the real power of the GIMP.

By now you should be very comfortable with using layers to make new images.

You keep your Layers dialog visible and you know how to use it. You’ve used layers for newly created text, and for objects pasted or dragged from other images. You know how to link several layers together to move them as a group, and apply transforms or other GIMP operations to a single layer. In addition, you’ve learned some basic GIMP tools such as the Move tool and the color chooser.

You’re ready for anything. With that in mind, it’s time to lighten up a bit, take what you’ve learned about layers, and apply that knowledge to a really fun aspect of the GIMP: drawing.

Now you know how to draw on layers, and have an idea when to make a new layer. You can draw lines, curves, and shapes such as rectangles and circles, and you can outline them or fill them. You’ve seen the various types of brushes GIMP offers, and how to use them with each of GIMP’s painting tools. Finally, you’ve learned techniques of drawing, shading, filling with patterns, and using the Perspective Transform tool to model real-world objects.

You can use these techniques to draw just about anything you can think of. Just use a little patience, and a lot of layers.

Armed with this knowledge, it’s time to go back to looking at photographs and learning how to select specific pieces so that you can use them in your own projects.

By now, you should be familiar with a wide range of selection techniques. You’re familiar with the marching ants, but you know how to turn them off when they get in the way. You can make selections using color or contiguous regions, Bezier paths, the Intelligent Scissors, or the QuickMask. You can make simple selections into more complex ones by combining several selections in Add or Subtract mode, or by editing them in the Paths tool, the QuickMask, or as a channel mask.

In addition, you’ve seen how you can change the appearance of an image by using tools on only a selected part of that image, and you’ve worked with layer masks and seen how you can use gradients in a layer mask to combine two layers smoothly. You can save a selection to a channel or path, and restore earlier selections you saved that way.

Selections are useful in every aspect of image editing, but nowhere are they more useful than when working with digital photographs—especially photos that have something wrong with them that needs to be corrected. In the next chapter, let’s take another look at digital photographs, and explore some techniques for touching them up . . . or editing problematic objects out of an otherwise good photo.

By now you should have a fairly good collection of tools for touching up any problems you might see in your photos.

You can dim bright highlights, and enhance areas that are too dark. You can sharpen or blur specific points, or large regions of an image. You know how to paint unwanted objects out of a photograph or copy patterns from another part of the image (or even from a different image). If a photograph has an odd color cast, you’ve seen several ways to correct it.

These techniques can keep you busy for quite a while, especially if you have a large collection of photographs that could use some minor touch-up work of one sort or another.

But this is only a tiny sample of the toys the GIMP has to offer! In the next chapter, let’s explore some of the other filters, plug-ins, and tools buried within the GIMP.

Well, that’s quite a list of toys! When you first installed GIMP you probably played around with a few of the filters, but it’s easy to miss some of the most useful functions GIMP has stuffed in its menus.

Now you should know when to look in the Toolbox menus versus the menus in the image window. You’ve experimented with the GIMP’s offerings for changing lighting and shadow, adding noise, and detecting edges. You can map images to three-dimensional objects with the Map filters and turn them into art with the Artistic filters. You know how to create interesting logos and other text effects, and how to make images for your web pages.

Some of these techniques are helpful for working with photographs, but you’ll find that they’re even more useful when making drawings. You worked with basic drawing tools in Chapter 4, but now that you’re familiar with heavy-duty image-processing techniques, you can go far beyond the simple examples from that chapter.

So take a firm grip on your mouse (or drawing tablet, if you have one) as we move into the next chapter and learn some techniques for advanced drawing.

If you’ve made it this far, you’re well on your way to becoming a GIMP plug-in writer—and if you choose, perhaps a developer for the GIMP itself.

You can develop your plug-in authoring skills by exploring the existing scripts and plug-ins, reading the documentation available on the GIMP website, and writing your own new plug-ins. Whether you’re tweaking existing scripts, writing quick scripts for your own use, or developing polished plug-ins intended for distribution, don’t be afraid to explore and try new things!

More than any other part of the GIMP, plug-in writing benefits from good documentation. This book isn’t intended to be a complete reference manual on GIMP programming; it only scratches the surface. You’ll want to become very familiar with the online documentation and existing tutorials.

If you’re wondering where to find all these web resources, keep reading. Chapter 12 will discuss the wealth of GIMP information on the web, as well as a few other topics such as GIMP’s configuration files, screen shots, and printing.

By now you know how to create your own brushes, patterns, and gradients. You know all about perspective and how to use it when drawing, how to make shadows, and how to make text or other objects fade out using layer masks. And you have some idea of the effects you can achieve by combining the GIMP’s many layer modes in your drawings.

Next, it’s time to revisit photographs, and see how you can use some of these same techniques to make your photos better, or to combine several photographs together . . . a process called compositing.

Now you know all sorts of ways to composite several images. No book could possibly list all the amazing things you can do compositing images in the GIMP, but now you know the important tools and a collection of different techniques. You should have a good solid base from which to begin experimenting with your own images.

You’ll also be able to apply techniques you find in web tutorials. If you experiment with these ideas, and try them on the sorts of images you use yourself, you’ll be an expert in no time.

But for now, take a break from fiddling with images by hand. During the course of this chapter, you’ve done quite a lot of repetitive operations which would have been so much easier if they were automated. In the next chapter, you’ll learn how to automate GIMP processes yourself, using plug-ins and scripting.