How to Use GIMP for Photo and Image Editing

MozillaQuest the on-line computer magazine

January 5, 2004

Office and Productivity Software

SCO IP, SCO v Linux, & Caldera v IBM

Mike Angelo's Digital Darkroom

Use GIMP rather than Photoshop and save money

Mike Angelo -- 5 January 2004 (C) -- Page 2

Article Index

Introduction

Overview of Tutorial

The Hands-On GIMP Tutorial

Getting Started
Into the Digital Darkroom
The first cropping
Sizing your photograph
Brightening things up
Finished
On your own

About the Geese Photo

GIMP v Photo$hop

Photoshop & GIMP Licensing Note
Adobe Product Activation Note

Conclusions

Resources

Books

To learn why Linux is so much a better choice than is Microsoft Windows, please see our article Gaël Duval Tells Why Mandrake Linux Is Better Than MS Windows

To learn how to run MS Windows-based software and accessories in GNU-Linux, please see our article Crossover Office 2.1 Runs MS Windows Software on GNU-Linux Systems

Dialogs and Palettes Note:

If you are a Photoshop user, please note that palettes in Photoshop are called dialogs (as in dialog boxes) in GIMP.

Into the Digital Darkroom

Let's enter the digital darkroom and start this lesson by opening the GIMP. That should bring up the GIMP Toolbox and the default combination dialog box.

(In pre-1.3 GIMP versions there are no combo dialog boxes they each are individual, rather than combo, boxes. If you are a Photoshop user, please note that palettes in Photoshop are called dialogs (as in dialog boxes) in GIMP.)

The Toolbox is the upper left box in Figure 1, on page 1, and the combination dialog box is the lower left box in Figure 1. Click on the leftmost icon in the combination dialog box to display the Tool Options.

Next, open an image that you want to use for this tutorial. To do that, go to the Menu Bar of the GIMP Tool Box, click on File > Open to bring up the Open Image dialog box. Then navigate to the image file that you wish to open and open it.

If you do not have an image to use for this tutorial, simply use the GIMP to take a screen shot and use that screen shot for working through this tutorial. To take a screen shot simply go to the Menu Bar of the GIMP Tool Box and click on File > Acquire > Screen Shot to bring up the Screen Shot dialog box.

In the Screen Shot dialog box, click on the Whole Screen radio button to set it active. Next, please click on OK.

That should bring up a GIMP canvass or workspace window with an image of the entire monitor screen at the time you made the screen shot.

Whether you have opened an image from your files or taken a screen shot to use for this tutorial, it should resemble the canvass window in the upper right of Figure 1, except your image or screen shot will be in the canvass window rather than our geese.

In Figure 1, all the boxes and the canvass window were packed together in order to make a compact screen shot for the figure. However, as you have been opening the dialog panels and image canvass, you might have noticed they are not packed together (docked). Rather they are floating separately.

The floating dialog panels and canvass are nice as they let you arrange your entire screen to let you work the way you like to work. You also can dock them together if you like. However, arranging your workspace and docking are not part of today's tutorial.

Before you start any actual editing of a photo or other image, it is a good practice to make a backup copy of it. That way if you mess up while making your edits, you still have an intact copy of the original.

The first cropping

The real subject matter in the Figure 1 digital photograph is the geese. However, there is lots of pond in the shot too. In this instance, some of that surplusage is due to the camera having only a 3X optical zoom and the geese being far from the camera. Some of the surplusage is because in this exercise we want to use this graphic in a space that is only 250-pixels wide. That calls for some cropping in the digital darkroom.

Fortunately the original, before editing, photograph came out pretty decent. It would make a nice two-foot or wider print, pretty much as is. It also would look good, pretty much as is, on a 19-inch or larger computer screen. However, for this exercise the job is to produce a 250-pixel wide rendition of it for an online magazine article graphic (the headline graphic on page 1 of this tutorial).

The actual, original, digital photograph is 1600x1200 pixels (1,920,000 square pixels). The cropping will cut that down to 971x598 pixels (580,658 square pixels). That's a reduction in canvass size to about one-third (30%) the size of the original photo. Seventy per-cent of the original photograph is not about the geese.

The area inside the rectangle around the geese in Figure 1 is what will remain after the cropping. Everything outside of that rectangle will get snipped out in the cropping.

After the cropping, the remaining image will be scaled down to a 250-pixel wide graphic. If the original 1600x1200 pixel digital photo were not cropped prior to scaling, the geese would be too small to see well in the final 250-pixel wide photograph.

Also, the cropping and scaling brings the original photo file-size down from a 835-KB JPEG to a 14-KB JPEG. Keeping graphics file sizes down is very important for Web use.

To get a feel for just how big the original 1600x1200 pixel digital photo is, please take a look at Figure 2, Father Goose. This is just the Drake at his original size in the 1600x1200 digital photograph. The size of Father Goose alone is 533x380 pixels.

Figure 2. Father Goose.

This is just the Drake at his original size in the 1600x1200 digital photograph. The size of Father Goose alone is 533x380 pixels. Please see text for an explanation. (Geese photo by Mike Angelo)

It's a good practice to include a little extra in your photographs when you shoot them. You always can snip off the extra later. But once the shot is taken, you cannot add to it, at least not without using computer-imaging tricks after the shot is taken. Thus, one thing you likely will do when you bring a photo into your digital darkroom is to crop it.

Now that you have the GIMP and an image open, it's time to grab the digital scissors, do some snipping, and have some fun. So, let's get started with editing the image by cropping it.

Please look at the GIMP Toolbox in Figure 1, on page 1. The second icon from the left in the third row of tool icons is a knife icon. That's the cropping tool icon. Click it to open the crop tool. The crop tool is active in Figure 1.

Now, move the mouse pointer over the geese photo or whatever image you are editing. Please notice how the mouse-pointer changes into the crop-tool pointer as the mouse-pointer moves into the image/photo canvass.

Place the crop-tool pointer arrow at what will be the upper left corner of the cropped image. Then depress the mouse button and drag the crop-tool pointer to the bottom right of what will be the cropped image and release the mouse button.

That creates a box around what will be the cropped image. Please see the tight box around the geese in Figure 1. Let's call that box the crop box.

This procedure brings up the Crop and Resize dialog box shown under the geese canvass in Figure 1. Use the Crop and Resize dialog box to tweak the size and location of the crop box.

The Origin X and Y input boxes set the location of the crop box. In Figure 1, the crop box starts 318-pixels in from the left edge of the canvass (X) and 302-pixels up from the bottom of the canvas (Y). That puts the origin of the crop box at the bottom left of the crop box.

The Width and Height input boxes set the dimensions (size) of the crop box. In Figure 1, the crop box is 971-pixels wide and 598-pixels high.

Even if your initial drawing of the crop box is perfect, try incrementing and decrementing the four input boxes to see how they adjust the location and size of the crop box.

When you have the crop box just the way you want it, click the Crop button in the Crop & Resize dialog box.