Learning in a digital world

Gimp is similar to Adobe PhotoShop with one important difference, it is free.

Note: Irfanview can be used to resize, crop, and change the image format. For most other tasks use Gimp.

Bitmap and vector images:
There are two kinds of images, bitmap and vector images.

A bitmap image is made up a rectangular array of pixels (picture elements). A bitmap image can not be enlarged without losing quality. Examples of bitmap formats are bmp, jpeg, jpg, gif, and png. Gimp lets you manipulate bitmap images.

Vector images are made up objects defined by mathematical equations rather than pixels. A vector image can be enlarged without losing quality.

Resources:

1. http://www.gimp.org/ – official Gimp site
2. http://www.gimp.org/downloads/ – download Gimp
3. http://docs.gimp.org/2.6/en/index.html – user manual (the help files)
4. ftp://ftp.gimp.org/pub/gimp/help/ – download the manual and put on your server for faster access
5. http://www.gimp.org/tutorials/ – tutorials
6. http://www.gimp.org/books/ – books on Gimp
7. http://gimp-savvy.com/BOOK/ – online book by Carey Bunks (download it for for faster access)
8. http://www.learngimp.info/ – blog
9. http://forum.meetthegimp.org/ and http://www.gimpusers.com/forums/ – forums where you can ask questions when you are stuck

Context sensitive help
Edit – Preferences – Help System lets you see context sensitive help offline in your browser if you first run gimp-help-2-2.6.0-en-setup.exe. I have not been able to install GIMP’s browser, but my default browser (Chrome) works just fine, as I am sure Firefox will do too.

Images without copyright:
There are several places where you can find images you can use more or less freely. Here are some.

1. http://commons.wikimedia.org/wiki/Main_Page
2. http://www.nasa.gov/gallery/photo
3. http://images.jsc.nasa.gov
4. http://nix.nasa.gov
5. http://www.photolib.noaa.gov
6. http://pictures.fws.gov
7. http://www.freedigitalphotos.net/. ( “Images can be used freely in school projects.”)

Learn to learn:

1. Press F1 to read the manual. Not all of it, but what you want to know more about.
2. Select Context Help in the Help menu and move the question mark to what you want to learn more about, a menu for example.
3. Experiment! Try what happens if…?
4. Talk to your fellow students. What have they discovered? Can they help you? Can you help them?
5. Study tutorials on the Internet.
6. In class we will only have time to discuss some techniques. You can learn much more if you are curious, persistent, and patient.

Note:

I have never used Photoshop and I have only played with Gimp for a few days. Please inform me of errors and suggest improvements.

Basics:

1. An image consists of layers that can be edited independently.
2. Click Ctrl+L to open the Layers Dialogue box.
3. If you close the Toolbox you close Gimp.
4. Save your image as Gimp xcf  to edit it in the future.
5. Save you image as Jpeg image to use the image on a web page or in a document.
6. Use Ctrl+ and Ctrl- to zoom.

Making a new Gimp image.

A Gimp image consists of several images each in its own layer. The bottom layer is called the background layer. Each layer can be manipulated without effecting the other layers.

To make a new Gimp image select New on the File menu. Decide on the width and height and click OK. The width and height is called the canvas size. No layer should be bigger than the canvas size.

Your turn -> Make a new Gimp image with width = 1017 and height = 829 pixels. Save the file as task1.xcf in your H folder.

Adding an image on a web page to a layer.

If the image is on a web page, right-click it and select Copy Image to copy it to the clipboard. Go to Gimp and press Ctrl+L to open the Layers Dialogue box. Then use Ctrl+V to paste the image. Finally, click the Anchor icon at the bottom of the Layers Dialogue box.

Your turn -> Add this image to the background layer. (click ‘this image’)

Adding a saved image to a layer.

If the image is already saved on your hard disk or memory stick select Open as Layers on the File menu.

Your turn -> Add any image in your H folder to a new layer.

Manipulating layers.

Click Ctrl+L if the Layers Dialogue box is not visible. At the bottom of the box there are icons for creating a new layer, moving a layer up or down, duplicating a layer, anchor a floating selection, and deleting a layer. To rename a layer just double-click the name and type a new name.

Your turn -> Delete the layer with the image from your H folder.

Your turn -> Find an image of a cow and add it to a layer you call cow. Make sure the image is not bigger than the canvas size.

Your turn -> Do the same for an image of a horse, sheep, pig, and rooster. When you have finished you should have five layers: cow, horse, sheep, pig, and rooster.

Use selection tools to remove part of an image.

One common task in image manipulation is to cut out part of an image so it can be used as a layer in another image.

One way to do this is using a selection tool. There are six of them in the Toolbox.

Your turn -> Cut out the cow from its background using the Scissors Select Tool.

Start with something like this:

And end up with something like this:

Your turn -> Cut out the other animals from their background, resize and position them on the background given above. Use the Free Select Tool followed with use of the Eraser, or use the Scissors Select Tool.

The cow in place:

(to be continued)

Would you like to create this animation? With Gimp you can.