Difference between revisions of "The Gimp"

Revision as of 11:32, 27 October 2006

About the class

Oso Says "Take the Gimp Class!

April, 2005 was the first time MNR offers a class on the Gimp at Free Geek, but it's far from the first time he's taught the subject. The Gimp is the image editing software distributed on FreekBoxes - and used by all kinds of people to make cool pictures. This is an introductory-level class, and should be accessable to anyone who has mastered the material taught in the FreekBox Adoption Class.

Class 1: Starting and Selections

right-click to download today's suggested image

Finding and starting the Gimp
Navigating the Gimp
Opening files, Saving Files
Freegeeks - Use Offline storage! Classroom machines are wiped clean every evening.
Help! Using context sensitive help
Palettes: Tools & Layers, (but not Channels or Paths)
Making selections
Dealing with Floating Selections

Something fun - change the color of the background.

use the elliptical select tool to select the earth in today's suggested image
float the selection
convert the selection to a new layer
change the foreground color (click on the black box in the tool palette)
add a new layer with a colored background (shift - new layer)
move the layers so the colored layer is underneath the earth

Class 2: Color select and Magic wand

Right-click to download today's suggested image

Brief review
Resizing images, resizing selections
Color Select Tool
Magic Wand
Something fun - Float the rocket or the jellyfish (right click on the link to download)

open today's suggested image
open the rocket or jellyfish
use the layer palette to add an alpha channel how to do it
Remove the background of the rocket or jellyfish by clicking on the background with the magic wand or color selection tool. (hint - the rocket is easier)
drag the layer (from the rocket or jellyfish layer panel) into the space cloud image

Class 3: Edges, tools, fills, paths

Right click to download today's suggested image

Edge Select
Move, Rotate, shear, perspective & flip
Fill, Gradient, pattern paint
Quick mask & save to path. (tutorial on quickmask)
path to selection
Manipulating Selections
Filters

Something fun - isolate Rosie from the background

Use the edge select tool, save to path and quickmask to create a selection around Rosie
duplicate the background
Select and float Rosie to a new layer. Turn off her visibility
use the motion filter on the duplicated background
Turn the "floated" version of Rosie back on.

Class 4: animations

An example of GIMP animations

Today's image (warning, 4 megabytes) contains XCF files for use with GIMP

Animations

Tutorial on Gimp Animation

Class 5: paths

Right click to download this sample image

When you open this document, be sure to "Import Paths"
The Paths dialog
Selection to path
Path to selection
Stroking a path
The Path Tool
- getting the path menu
Path from text

Class 6: Common tasks

Red eye removal
Saving for the web
Reducing the size of an image

Class 7: Fixing Images

A crappy photo taken with a cell phone. Right click to save this to your desktop

Color Tools - Levels This tool can be used to adjust colors. It will be easier to understand this tool if you understand histograms.

  * Use the Black Eyedropper to pick a black point.
  * Use the White Eyedropper to pick a white point.
  * Adjust mid-tones using the slider.
  * Color cast can be adjusted using the channels and eyedroppers

A less-than-stellar photo. Right click to save this to your desktop

The same photo after adjusting color and sharpening

If we wind up talking about color correction, you're going to need a color wheel

Frequently asked "How do I ... "

...Save to a jpeg?
...Save to a GIF?
...Remove the background or isolate a part of the foreground? There are some basic steps...
- Don't forget to add an alpha channel
- You may want to duplicate the layer first
- Select the layer you want to work on
- Select the area you want to remove (or isolate) using one of the selection tools
- Delete the selection

@@ Line 44: / Line 44: @@
 == Class 3: Edges, tools, fills, paths ==
 [http://memory.loc.gov/service/pnp/fsac/1a35000/1a35300/1a35371v.jpg Right click to download today's suggested image]
-* [http://docs.gimp.org/en/ch07s02s07.html Edge Select]
+* [http://docs.gimp.org/en/gimp-tool-iscissors.html Edge Select]
-* [http://docs.gimp.org/en/ch07s04.html Move], [http://docs.gimp.org/en/ch07s04s03.html Rotate], [http://docs.gimp.org/en/ch07s04s05.html shear], [http://docs.gimp.org/en/ch07s04s06.html perspective] & [http://docs.gimp.org/en/ch07s04s07.html flip]
+* [http://docs.gimp.org/en/gimp-tool-move.html Move], [http://docs.gimp.org/en/gimp-tool-rotate.html Rotate], [http://docs.gimp.org/en/gimp-tool-shear.html shear], [http://docs.gimp.org/en/gimp-tool-perspective.html perspective] & [http://docs.gimp.org/en/gimp-tool-flip.html flip]
 * Fill, Gradient, pattern paint
-* [http://docs.gimp.org/en/ch02s04s02.html Quick mask] & save to path. ([http://www.gimp.org/tutorials/Quickmask/ tutorial on quickmask])
+* [http://docs.gimp.org/en/gimp-channel-dialog.html#gimp-qmask Quick mask] & save to path. ([http://www.gimp.org/tutorials/Quickmask/ tutorial on quickmask])
 * path to selection
 * Manipulating Selections