GIMP
From TechHelp
The GIMP is an Open Source digital photography tool. This tool has a lot of different tools to work with images.
Contents |
[edit] Basic Tools
When you first open the GIMP two windows will open. Both of these are related to the program. One window is labeled The GIMP, which is where most of your tools and menus will be.
The other menu is labeled Layer, Channels, and Patterns, which will show you different information regarding the colors and other information that you are working with.
The first thing that you have to do to work with the GIMP is open a picture. If you have a digital camera or scanner connected to your computer you will want go to File > Aquire > Scanner/Camera which will pop open another window showing you a list of cameras that are connected and turned on. From here you will be able to pick the image that you want to work with. One of the first things you should do is a File > Save As
If the image that you are working on is already saved on your computer you can simply click on File>Open and this will open a window that will let you browse to the location of the file you wish to open.
Once you have an image open you will also notice that in the window that the image opens in will also have a menu
[edit] Crop
Once you have opened the image the first thing that most people will want to be able to do is crop the photo.
In photography there are different techniques such is what is called the rule of thirds. Photographers that want to take advantage of this rule can use the crop tool to create a photograph
Using the crop tool you can take an image that might not be appeasing to the eye and manipulate it so that it looks completely different. Perhaps you have a picture that could be framed by a window, but you shot the image a little too wide. So you have this blank wall around the window. By selecting the crop tool you can take the wall away and keep just the window frame and its contents.
To do this you will need to select the crop tool, which looks like this 
. To use the tool simply click and drag across the area of the image that you want to keep. You will also notice that when you do this you are given a pop up screen that talks about the axis, point of origin, and aspect ratio. By changing these values you can manipulate the area that you are cropping with a lot of precision. The origin X will move the area left or right. The origin Y will move the area you are cropping up and down. Changing the width will move the right hand side of the area that you are cropping. The height will move the bottom of the area that you are cropping.
The aspect ration will change the area so that the width is a specific proportion to the height.
[edit] Resize
The real difference between cropping and resizing an image is that during cropping you are usually eliminating areas of the photo. When resizing you are making the physical characteristics of the image change. So instead of an image being a 3 by 5 you change it to a 2 x 2.5 where by cropping you are actually cutting the image down. To resize an image using the Gimp go to Image > Scale Image. This will bring up a window that gives you
[edit] Rotate
Some pictures that you may be importing or working on will need to be rotated. The GIMP like most other image manipulation software allows you to simply adjust the parameters of an image, rotating it and flipping it till it is where you want it. To rotate the entire image you will want to go to Image > Transform > Rotate , which allows you to rotate 90 and 180 degrees in different directions.
If these selections don't fit your needs you can also use the rotate tool in the Gimp window 
. This tool gives you the ability to refine what it is that you are trying to do. By selecting the tool and then clicking on the image you will open a simple dialog box that allows you to use a slider, the specific angle, as well as adjust the center point as you rotate the image.
[edit] Basic Tools
Some common tasks that you may end up doing in the GIMP usually involve a certain spectrum of tools. Here you will find out some of the basic groups and what you would do with them.
[edit] Selection Tools
There are four basic tools that allow you to select information within an image.
- Rectangular Selection
- Selects a rectangular area
- Oval Selection
- Selects a oval area
- Free Selection
- Selects an closed area that you create
- Fuzzy Selection
- This is a best guess selection tool
Each of these tools will allow you to take away pieces of your image or affect a specific area by selecting it first. Once you have the area selected you can try to touch it up, cut it out of the picture, or replace it with another area.
[edit] Healing Tool
The healing tool in the Gimp is a very powerful tool that can help you fix small imperfections in a picture. Say for example that you have scanned a picture and there is a hair line crack in the photo or you have taken a picture of the sky but happened to be under the power lines. In either of these cases using the healing tool 
will help you fix these imperfections.
To use the tool you will want to select the image that you have the imperfection in. Then I tend to zoom close to the area I want to fix. This helps me work, but may not be the best way for you to work. Once you are in the area that you want to fix you will select the healing tool. The way this tool works is that it uses a certain part of the picture that you determine is good and resample over it. You use the key combination of CTRL and Click to select the source. Then by simply clicking and dragging you will be replacing the imperfection with the source that you selected.
[edit] Color
If you are actually creating your own image one or adding text or basic shapes to a image it is good to have a concept of how to add and change the colors that you have available to you.
In the GIMP tool bar you will see the basic color switcher that is available to you.
By default it usually contains black and white, but any array of colors can be added and changed as you work with your image.
To access a variety of colors you will want to simply click either on the foreground or background color in the color switcher. This will bring up a large pallet for you to choose from.
[edit] Layers
As with Photoshop the GIMP allows you to use layers to create more dynamic photos. However unlike Photoshop the way you work with layers is a bit different, though the same basic concepts apply.
When you first open up a basic jpg image file you will see that there is a background layer in the menu containing the layers menu.
Most pictures start out as a single layer if they are the common file types, such as jpg, gif, and tiff. When you start to add things such as text or drawings to an image you will begin to see layers added to the image.
If you have an image and want to add a title to that image you would simply click on the text tool to begin to add the text. Now if you wanted to add an effect to the original image you would need to make sure that the image, not the text layer is selected. This way you will only affect the image layer, without affecting the text. Layers let you also create opacity of an item. Think of layers as you would overheads that you lay on top of each other to show different parts of a map.
If you are trying to create your own images you will want to click on the little arrow menu in the layer menu. This will open a new window that gives you some options on how to create the layer. Depending on what you want to see above, below, and how large you want the layer will determine what you will choose.
Once you have selected these things you will have a new layer to choose from as you work on your image.
[edit] Printing
The Gimp allows you to print an image if that is the final goal. The options are pretty basic, basically you will want to find the best fit for your image whether it is a landscape or a portrait type of an image.
Then you will want to go to the image that you want to print. From the menu above that picture you will want to choose File > Print. Which will bring up a window where you can choose the type of printer that you would like to use.
