Class IX · Chapter 39 min read
Chapter 3: Introduction to GIMP
Class: IX | Subject: Information and Computer Technology
Key Concepts
1. Image Editing, Introduction, Image editing encompasses the processes of altering images, whether digital photographs, traditional analog photographs, or illustrations., Traditional analog image editing is known as photo retouching (using tools like an airbrush)., Two basic ways images can be adjusted:
- Pixel editing: Works at the pixel level, requires altering the original image.
- Parametric Image Editing: Saves instruction sets that change the appearance without changing the original image data.
2. Commonly Used Image Editing Tools
| Tool | Key Feature |
|---|---|
| GIMP | Free, open source; retouching, authoring, composition of photos |
| FastStone Image Viewer | Browsing, editing, converting; 150+ transitional effects |
| Serif PhotoPlus X4 | User-friendly; photos organizer, scrapbooking, web galleries |
| Photo Impression 6.5 | Simple editing; auto-organizes photos |
| PhotoStudio 6 | Animated text, stamping, layers support |
| Picasa | Quick crop and editing; easy to use for casual users |
| Paint.net | Easy interface; unlimited undo; popular among Windows users |
| Photo! Editor | Complete set of editing tools for digital camera owners |
| Inkscape | Open source; vector-based; node-editing, bitmap tracing, alpha blending |
| Corel PaintShop Photo Pro X3 | Integrated organizer with advanced enhancement tools |
3. GIMP (GNU Image Manipulation Program)
- Free and open source image editing tool., Provides retouching, authoring, and composition of photos., Similar features to Adobe Photoshop., Multi-platform: GNU/Linux, Microsoft Windows, Mac OS X., Covered by the General Public License (GPL), users can access and alter the source code., Originally released by Spencer Kimball and Peter Mattis; development began in 1995 at the University of California, Berkeley.
Features of GIMP, Can be used as a simple paint program, Expert quality photo retouching, Online batch processing system, Mass production image renderer, Advanced scripting interface, Converts and saves files to many formats (GIF, JPEG, TIFF, etc.), Loads and saves animations (frame as layer format), Virtually unlimited images can be opened at one time, Works with Linux, Mac OS, and Microsoft Windows, Also available on Android via Ubuntu no root package from Google Play Store
Supported File Formats
| Format | Expansion |
|---|---|
| TIFF | Tagged Image File Format |
| XWD | X Window System |
| JPEG | Joint Photographic Experts Group |
| XPM | X Pixmap |
| GIF | Graphics Interchange Format |
| PNG | Portable Network Graphics |
| PSD | Photoshop Document |
| PPM | Portable PixMap |
| BMP | Bitmap |
| PCS | Personal Computer Exchange |
Compatible Platforms, GNU/Linux (i386, PPC), Microsoft Windows (XP, Vista, Windows 7), Mac OS X, Sun OpenSolaris, FreeBSD
4. Starting GIMP
- Open: Start --> All Programs --> GIMP 2
- Create New File: File --> New (Ctrl+N) --> Choose template or set width/height --> OK
- Open Existing File: File --> Open (Ctrl+O) --> Select file --> Open
- Save a File: File --> Save (Ctrl+S) or Save As (Shift+Ctrl+S) --> Name the file, select format, click Save
5. Understanding the GIMP Window
| Component | Description |
|---|---|
| Title Bar | Also called Emphasis Bar; at the top; shows image name and basic info |
| Menu Bar | Below title bar; gives access to nearly every operation |
| Toolbox | Quick access to basic tasks like making selections or drawing paths |
| Ruler | Above and to the left of the image; shows coordinates (default: pixels). Click on ruler to create guidelines for accurate positioning |
| Status Bar | At the bottom; shows active part of image and system memory consumption |
| Canvas | Central area; the image display area surrounded by a yellow dotted line showing image boundary |
6. Toolbox, Selection Tools
| Tool | Shortcut | Description |
|---|---|---|
| Rectangle Select | R | Selects rectangular regions of the active layer |
| Oval Selection | E | Selects circular and elliptical regions |
| Lasso (Free Selection) | F | Free-hand selection by drawing with the pointer |
| Fuzzy Selection (Magic Wand) | U | Selects areas based on colour similarity; good for objects with sharp edges |
| Select By Colour | Shift+O | Selects all pixels with similar colour regardless of location (unlike Magic Wand which requires contiguity) |
7. Toolbox, Other Tools
| Tool | Shortcut | Description |
|---|---|---|
| Text | T | Places text into an image on the canvas |
| Eraser | Shift+E | Removes areas of colour from the current layer or selection |
| Bucket Fill | Shift+B | Fills a selection with the current foreground colour (Ctrl+click uses background colour) |
8. Toolbox, Complete Tool List
Rectangle Select, Oval Select, Lasso, Fuzzy Select, Select by Colour, Scissors, Foreground Select, Paths, Colour Picker, Zoom, Measure, Move, Alignment, Crop, Rotate, Scale, Shear, Perspective, Flip, Cage Transform, Text, Bucket Fill, Blend, Pencil, Paintbrush, Eraser, Airbrush, Ink, Clone, Heal, Blur/Sharpen, Smudge, Dodge/Burn.
9. Colour Area, Shows GIMP's basic palette: Foreground and Background colours., Used for painting, filling, and many other operations., Click on either colour to open the Colour Editor dialog to change it.
10. Menus of GIMP Window
File Menu (Ctrl+N, Ctrl+O, Ctrl+S, etc.)
New, Create, Open, Open as Layers, Open Location, Open Recent, Save, Save As, Save a Copy, Revert, Export, Print, Close, Quit.
Edit Menu
Undo, Redo, Fade, Undo History, Cut, Copy, Copy Visible, Paste, Paste Into, Paste as, Buffer, Clear, Fill with FG/BG Color/Pattern, Stroke Selection, Stroke Path, Preferences.
Image Menu
Duplicate (Ctrl+D), Mode, Transform, Canvas Size, Fit Canvas to Layers/Selection, Print Size, Scale Image, Crop to Selection, Autocrop, Zealous Crop, Merge Visible Layers (Ctrl+M), Flatten Image, Align Visible Layers, Guides, Configure Grid, Image Properties.
11. Editing Images
Changing Image Size (Scale)
- Go to Image --> Scale Image
- Set the width and height values
- Set the resolution
- Set the interpolation quality (e.g., Cubic)
- Click "Scale" to confirm
Preparing Images for Web
- Reduce image to appropriate width and height for web
- File --> Export
- In JPEG Save Dialog, adjust the "Quality" slider down to reduce file size without hurting visual quality too much
Cropping an Image, Used to select a specified area and remove everything outside it., Access: Toolbox crop button OR Tools --> Transform Tools --> Crop & Resize (Shift+C), Click on approximate upper left corner and drag to lower right corner.
12. Layers, Layers are like transparent sheets stacked on top of each other., Lower layers show through, resulting in a composite image., The composite can be exported as a flat file (JPEG, PNG)., Separate elements of the composite can be kept on separate layers for easy editing., Layers are covered in detail in Class X.
Important Definitions
| Term | Definition |
|---|---|
| Image Editing | The process of altering images (digital, analog, or illustrations) |
| Photo Retouching | Traditional analog image editing using tools like airbrushes |
| Pixel Editing | Working at the pixel level, altering the original image |
| Parametric Image Editing | Saving instruction sets that change appearance without altering original data |
| GIMP | GNU Image Manipulation Program, free, open source image editing tool |
| GPL | General Public License, allows users to access and alter source code |
| Canvas | The central area of the GIMP window where the image is displayed |
| Toolbox | A collection of tools for quickly performing basic tasks in GIMP |
| Ruler | Shows coordinates within the image; used to create guidelines |
| Layer | A transparent sheet; multiple layers stack to form a composite image |
| Scale | Changing the size (width/height) of an image |
| Crop | Selecting a specific area and removing everything outside it |
| Magic Wand | Fuzzy selection tool that selects areas based on colour similarity |
Key Points
- GIMP stands for GNU Image Manipulation Program, it is free and open source.
- GIMP supports many file formats: TIFF, JPEG, GIF, PNG, PSD, BMP, etc.
- GIMP works on Linux, Windows, Mac OS X, and other platforms.
- The GIMP window has six main components: Title Bar, Menu Bar, Toolbox, Ruler, Status Bar, Canvas.
- The Rectangle Select tool is the most basic selection tool.
- Magic Wand selects contiguous regions; Select By Colour selects all similar pixels regardless of location.
- The Eraser shows the background colour when used on a layer without transparency.
- Bucket Fill uses foreground colour by default; Ctrl+click uses background colour.
- Scale Image changes the size of an image; you should set resolution and interpolation quality.
- For web images, reduce dimensions and adjust JPEG quality to reduce file size.
- Crop removes everything outside the selected area.
- Layers are like transparent sheets stacked up; they enable non-destructive editing.
Practice Questions
- What is image editing?
- List a few image editing tools available.
- Explain GNU Image Manipulation Program.
- What is photo retouching?
- Write down the expansions of: .gif, .png, .tff, .jpeg, .jpg, .psd, .bmp
- Discuss how to change the size of an image.
- How can we prepare images for the web?
- What do you understand by Layers?
- What are the components of the GIMP window?
- Explain the difference between Fuzzy Select and Select by Colour tools.
Lab Activities, Take a family picture and change background/clothes colour using paint tools., Design a birthday party invitation using appropriate tools., Import an image, change foreground/background colour, add text, select a portion and change direction., Make a collage on "Heritage of India.", Design a digital poster on "Global Warming."
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