Gimp bible

GIMP Bible GIMP Bible Jason van Gumster Robert Shimonski Wiley Publishing, Inc. GIMP Bible Published by Wiley Publishing, Inc. 10475 Crosspoint Boulevard Indianapolis, IN 46256 www.wiley.com Copyright © 2010 by Wiley Publishing, Inc., Indianapolis, Indiana Published by Wiley Publishing, Inc., Indianapolis, Indiana Published simultaneously in Canada ISBN: 978-0-470-52397-1 Manufactured in the United States of America 10 9 8 7 6 5 4 3 2 1 No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. 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Library of Congress Control Number: 2009943686 Trademarks: Wiley and the Wiley logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. All other trademarks are the property of their respective owners. Wiley Publishing, Inc. is not associated with any product or vendor mentioned in this book. To my mother, who once made the mistake of telling me I could do anything I set my mind to do . . . only to have me terrorize her by trying to do everything. — Jason van Gumster This book is dedicated to my son, Dylan James. — Robert Shimonski About the Authors Jason van Gumster got into animation when he realized that he wanted to create movies . . . but that actors are generally intolerant of having pianos dropped on them. Using open source tools at nearly every step in production, Jason has produced animations and visual effects for television, film, and video games in his official capacity as a ‘‘Production Monkey’’ for Hand Turkey Studios, the company he helped start in 2005. He uses GIMP and the GIMP Anima- tion Package on a daily basis for a variety of tasks ranging from creating graphics for the Web and television to drawing storyboards and creating images for both 3D and hand-drawn anima- tions. Also the author of Blender for Dummies, Jason has given numerous live workshops and demonstrations on Blender internationally. Combining a unique educational background in ani- mation and computer engineering with a penchant for the ridiculous, he strives to refine both the technical and creative aspects of production by taking on (and successfully completing) crazy projects like producing a 5-minute 3D animated short in a mere 48 hours with an international team communicating via the Internet. Based in Richmond, Virginia, Jason can often be found in cafe´s and diners drawing, espousing the virtues of open source software, or catching confused looks from strangers as he contorts his body to better visualize a scene he’s animating. Robert J. Shimonski is an expert digital media and technology consultant living in New York. Rob is also an author, and a regular contributor of tutorials and articles on digital editing, pro- duction, and development. Having spent the past decade working with large, medium, and small companies as a techni- cal consultant, Rob has helped develop digital art packages for many professional clients and businesses. Rob has been working with GIMP for many years and has created graphics for corporate web sites, TV commercials, and professional magazines. Having worked with the many open source tools, Rob relies on GIMP for most of his graphics work. Rob can be found online at www.shimonski.com. About the Technical Editor John Karnay is a published author and editor with over a dozen works to his credit. He has been writing and editing in the fields of technology, fiction, comic books, computer software, music, and video games for over 15 years. John is a computer software, audio engineering, graphic design, networking and IT specialist who has been working with and deploying Microsoft-, Apple-, and open source-based technologies for over 15 years. He also specializes in Spanish-to-English translation. John currently works in the video game industry as a producer, content writer and quality assurance manager and has over 30 game titles to his credit. John resides in Jackson Heights, New York and spends his free time with his daughter Aurora and with his loving wife and partner, illustrator Gloria Rios. Credits Executive Editor Carol Long Project Editor Sydney Jones Technical Editor John Karnay Production Editor Daniel Scribner Copy Editor Kim Cofer Editorial Director Robyn B. Siesky Editorial Manager Mary Beth Wakefield Associate Director of Marketing David Mayhew Production Manager Tim Tate Vice President and Executive Group Publisher Richard Swadley Vice President and Executive Publisher Barry Pruett Associate Publisher Jim Minatel Project Coordinator, Cover Lynsey Stanford Proofreader Heather Dweller Indexer Johnna VanHoose Dinse Cover Illustration Joyce Haughey Cover Designer Michael E. Trent F irst (and most important) thanks go to the surprisingly small group of dedicated develop-ers who voluntarily spend their free time coding GIMP. Most people don’t realize that aprogram of GIMP’s complexity is updated and maintained by only a handful of develop- ers whose primary motivation is the fact that they enjoy doing it. Your patience and help with my questions and misplaced bug reports are sincerely appreciated. You are not and cannot be thanked enough. Thanks, also, to the entire team at Wiley. Were it not for this talented group of professionals (and large quantities of coffee), this book would never have been produced. I’d especially like to acknowledge my project editor of unparalleled patience and tireless energy, Sydney Jones. I’d also like to thank Rob Shimonski not only for working as this book’s initial technical editor, but also for stepping up and agreeing to write a portion of the book on incredibly short notice. It has been a pleasure to work with both of you. — Jason van Gumster A book takes a lot of work to create and requires a very large team effort. I would like to thank the Wiley production team for all of their hard work. I would first like to thank my co-author Jason, who is truly a GIMP wizard. Special thanks goes out to Sydney for her untiring dedi- cation to this project. I would also like to thank technical editor Johnny for keeping things on track. Lastly, I would like to thank Carol, who got me started on the project and kept everything locked on. — Robert Shimonski xiii Introduction ..................................................................................................................................xxxi Part I: Meet GIMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Chapter 1: What Is GIMP? ................................................................................................................3 Chapter 2: Thinking Digitally .........................................................................................................41 Part II: Getting Started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 Chapter 3: Working with Files .......................................................................................................61 Chapter 4: A Brief Overview of GIMP’s Tools ...............................................................................93 Chapter 5: Taking Advantage of Paths .........................................................................................109 Chapter 6: Working with Layers and Masks ...............................................................................135 Chapter 7: Using Channels ...........................................................................................................171 Part III: Manipulating Images . . . . . . . . . . . . . . . . . . . . . . . . . . . 185 Chapter 8: Transforming Images ..................................................................................................187 Chapter 9: Adjusting Colors .........................................................................................................221 Chapter 10: Working with Text ...................................................................................................281 Chapter 11: Painting in GIMP ......................................................................................................297 Chapter 12: Enhancing Photos .....................................................................................................323 Part IV: Exploring Filters and Effects . . . . . . . . . . . . . . . . . . . . . 347 Chapter 13: Implementing Blur, Enhancement, and Distortion Filters ......................................349 Chapter 14: Using Image Creation Filters ....................................................................................391 Chapter 15: Using Compositing Filters ........................................................................................427 Chapter 16: Enhancing Images with Artistic Filters ....................................................................475 Chapter 17: Working with Specialized Filters .............................................................................499 Chapter 18: Batch Processing with Automating Filters ...............................................................513 Chapter 19: Using GIMP Animation Package ..............................................................................537 Chapter 20: Working with Video-Specific Functions in GIMP ...................................................567 Part V: Advanced Topics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 599 Chapter 21: Finding and Installing Plug-ins ................................................................................601 Chapter 22: Creating Custom Effects with Scripting ...................................................................629 xv Contents at a Glance Part VI: Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .647 Appendix A: Downloading and Installing GIMP .........................................................................649 Appendix B: Setting Up External Input Devices ..........................................................................663 Appendix C: Customizing GIMP ..................................................................................................679 Appendix D: Additional Resources ...............................................................................................691 Appendix E: What’s on the Web Site ...........................................................................................695 Index ..............................................................................................................................................697 xvi Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxxi Part I: Meet GIMP 1 Chapter 1: What Is GIMP? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 Knowing What GIMP Can and Cannot Do ............................................................................6 Working with GIMP’s Interface ..............................................................................................7 Windows and Menus ....................................................................................................7 Docks and Dialogs .........................................................................................................9 Images and Canvases ..................................................................................................16 Parts of the Image Window ..............................................................................16 The Concept of a ‘‘Canvas’’ ...............................................................................18 Setting Preferences .................................................................................................................21 The Module Manager ........................................................................................21 GIMP Preferences ..............................................................................................22 Customizing Keyboard Shortcuts .........................................................................................37 Summary ................................................................................................................................39 Chapter 2: Thinking Digitally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Digital Images vs. Traditional Photographs ..........................................................................41 Raster Graphics vs. Vector Graphics ....................................................................................44 Raster Images ...............................................................................................................44 Vector Images ..............................................................................................................44 Resolution and Image Size ....................................................................................................46 Changing Image Size and Resolution .........................................................................47 Confusing Terminology ...............................................................................................49 Color Depth ...........................................................................................................................50 Color Spaces and Color Modes ............................................................................................51 Color Spaces ................................................................................................................51 Color Modes ................................................................................................................52 Compression ..........................................................................................................................55 Lossless Compression ..................................................................................................55 Lossy Compression ......................................................................................................57 Summary ................................................................................................................................58 xvii Contents Part II: Getting Started 59 Chapter 3: Working with Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 Opening Files ........................................................................................................................61 Opening Images ..........................................................................................................62 File  Open ......................................................................................................62 Other Ways to Open an Image ........................................................................66 Creating a Blank New Image ......................................................................................68 Generating an Image from Plug-in or Hardware .......................................................69 Creating an Image from a Screenshot ..............................................................70 Creating an Image from a CMYK TIFF ............................................................72 Using a Scanner to Import a Drawing or Photograph .....................................73 Letting GIMP’s Automated Scripts Generate an Image ....................................74 Managing Open Images ..............................................................................................75 Working in the Image Window ............................................................................................77 Copying and Pasting .............................................................................................................79 Fun Things You Can Do with Paste (Besides Eat It) .................................................79 Advanced Copy and Paste with Buffers ..................................................................... 81 Taking Advantage of Undo ...................................................................................................82 Saving Files ............................................................................................................................84 GIMP’s Native Format: XCF .......................................................................................85 Other Formats .............................................................................................................86 Summary ................................................................................................................................90 Chapter 4: A Brief Overview of GIMP’s Tools . . . . . . . . . . . . . . . . . . . . 93 The View Menu .....................................................................................................................93 Modifying Your View in the Image Window .............................................................93 Using Display Filters to Color Correct GIMP to Your Monitor ................................96 Showing and Hiding Information ...............................................................................97 Snapping Controls .......................................................................................................98 Padding Color ............................................................................................................. 98 Showing and Hiding Parts of the Image Window .....................................................99 Selection Tools ...................................................................................................................... 99 Rectangle Select .........................................................................................................100 Ellipse Select ..............................................................................................................101 Free (Lasso) Select .....................................................................................................102 Fuzzy Select ...............................................................................................................102 Select by Color ..........................................................................................................103 Intelligent Scissors Select ..........................................................................................103 Foreground Select .....................................................................................................103 Image Tools .........................................................................................................................104 Informational Tools ...................................................................................................104 xviii Contents Color Picker ....................................................................................................104 Zoom ...............................................................................................................105 Measure ...........................................................................................................105 Transform Tools ........................................................................................................106 Paint Tools ...........................................................................................................................106 Color Tools ..........................................................................................................................106 Summary ..............................................................................................................................107 Chapter 5: Taking Advantage of Paths . . . . . . . . . . . . . . . . . . . . . . . . . 109 The Advantages of Paths: Get Some Vector in Your Raster ..............................................109 Creating Paths .....................................................................................................................110 Drawing with the Paths tool .....................................................................................111 Creating a Path from a Selection ..............................................................................114 Managing Paths ...................................................................................................................118 The Paths Dialog .......................................................................................................119 Importing and Exporting Paths ................................................................................121 Importing Paths ...............................................................................................121 Exporting Paths ...............................................................................................123 Using Paths ..........................................................................................................................123 Painting along a Path ................................................................................................124 Stroke Line ......................................................................................................125 Stroke with a Paint Tool .................................................................................126 Practical Example: Faking an Ink Drawing ....................................................129 Selecting with a Path .................................................................................................132 Summary ..............................................................................................................................133 Chapter 6: Working with Layers and Masks . . . . . . . . . . . . . . . . . . . . . 135 Managing Layers ..................................................................................................................136 A Quick Overview of the Layers Dialog ..................................................................136 Adding, Duplicating, and Removing Layers .............................................................139 Creating a New Layer .....................................................................................140 Duplicating an Existing Layer .........................................................................141 Deleting Layers ................................................................................................142 Arranging Layers in the Stack ...................................................................................142 Grouping and Merging Layers ..................................................................................143 Merging Layers ................................................................................................143 Grouping Layers ..............................................................................................144 Manipulating Layers ............................................................................................................146 Resizing Layers ..........................................................................................................146 Modifying the Layer Boundary Size ...............................................................146 Scaling Layers ..................................................................................................147 Offsetting the Content of a Layer ...................................................................148 Aligning Layers ..........................................................................................................149 xix Contents Working with Layer Transparency ...........................................................................152 Additional Layer Transparency Features ........................................................152 Using Layer Transparency for Selections .......................................................154 Blending Modes ...................................................................................................................156 Using Layer Masks ..............................................................................................................162 Defining Layer Masks ................................................................................................162 Modifying Layer Masks .............................................................................................163 Effectively Using Features in the Select Menu .........................................................165 Summary ..............................................................................................................................169 Chapter 7: Using Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171 Understanding Channels .....................................................................................................171 Red, Green, and Blue: The Default Color Channels ................................................172 A Fistful of Awesome: The Alpha Channel ..............................................................173 Using Channels ...................................................................................................................175 Creating Channels .....................................................................................................176 Taking Advantage of Channels Once They’re Created ............................................177 Practical Application: Changing the Background .....................................................179 Summary ..............................................................................................................................183 Part III: Manipulating Images 185 Chapter 8: Transforming Images . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187 Adjustments Available in the Image and Layer Menus ......................................................187 Sizing .........................................................................................................................188 Fit Canvas to Layers ........................................................................................188 Layer to Image Size .........................................................................................189 Cropping and Guillotine ...........................................................................................190 Crop to Selection ............................................................................................191 Autocrop ..........................................................................................................191 Zealous Crop ...................................................................................................193 Guillotine .........................................................................................................194 Flipping and Rotating ...............................................................................................195 Flipping ...........................................................................................................195 Rotating ...........................................................................................................196 Liquid Rescale: Quite Possibly the Coolest Thing Ever ...........................................198 Using Liquid Rescale .......................................................................................199 Output Options ...............................................................................................202 Advanced Options ...........................................................................................204 Interactive Mode .............................................................................................206 Advanced Techniques: Smart Zoom ...............................................................208 Using the Image Tools ........................................................................................................209 Alignment Tool .........................................................................................................209 Crop Tool ..................................................................................................................213 xx Contents Transformation Tool .................................................................................................215 Moving .............................................................................................................217 Rotating ...........................................................................................................218 Scaling .............................................................................................................218 Shearing ...........................................................................................................218 Changing Perspective ......................................................................................218 Flip Tool ....................................................................................................................219 Summary ..............................................................................................................................220 Chapter 9: Adjusting Colors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221 Using the Color Menu ........................................................................................................223 Working with the Color Tools .................................................................................223 Features Available for All Color Tools ...........................................................224 Color Balance ..................................................................................................226 Hue-Saturation ................................................................................................227 Colorize ...........................................................................................................229 Brightness-Contrast .........................................................................................230 Threshold ........................................................................................................231 Levels ...............................................................................................................232 Curves ..............................................................................................................236 Posterize .......................................................................................................... 239 Desaturate ........................................................................................................241 Inverting Values ........................................................................................................243 Using Automated Adjustments .................................................................................243 Equalize ...........................................................................................................244 White Balance ................................................................................................. 245 Color Enhance .................................................................................................245 Normalize ........................................................................................................246 Stretch Contrast .............................................................................................. 247 Stretch HSV .....................................................................................................248 Working with Separated Color Components ...........................................................249 Channel Mixer .................................................................................................249 Composing, Decomposing, and Recomposing ...............................................252 Remapping Colors .....................................................................................................255 Rearranging and Defining a Color Map .........................................................256 Alien Map ........................................................................................................257 Color Exchange ...............................................................................................258 Gradient Map ..................................................................................................260 Palette Map ......................................................................................................260 Rotate Colors ...................................................................................................260 Sample Colorize ..............................................................................................263 xxi Contents Analyzing Your Colors with Info Tools ....................................................................266 Histogram ........................................................................................................266 Border Average ................................................................................................267 Colorcube Analysis ..........................................................................................267 Smooth Palette ................................................................................................268 Color Filter Plug-ins ..................................................................................................269 Color to Alpha ................................................................................................269 Colorify ............................................................................................................269 Filter Pack .......................................................................................................269 Hot ...................................................................................................................272 Maximum RGB ................................................................................................272 Retinex .............................................................................................................273 Exporting Color Separations with the Separate+ Plug-in ..................................................275 Summary ..............................................................................................................................279 Chapter 10: Working with Text . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 281 Uses for Text in Images ......................................................................................................281 Adding and Editing Text ....................................................................................................282 Customizing Text from the Text Panel ....................................................................286 Font and Size ..................................................................................................286 Font Edging .....................................................................................................287 Changing Text Color ...................................................................................... 288 Justification, Indentation, and Spacing .......................................................... 289 Making Text Go Along a Path ..................................................................................290 Using Text to Create a Path ......................................................................................292 Working with Text Layers ..................................................................................................294 Summary ..............................................................................................................................296 Chapter 11: Painting in GIMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 297 Working with Brushes ........................................................................................................298 Adjusting Brushes ......................................................................................................299 Using Tool Options to Adjust Brushes ..........................................................299 Quickly Adjusting Brush Settings from the Image Window .........................302 Creating New Brushes ...............................................................................................303 Using the Brush Editor to Create Procedural Brushes .................................. 305 Creating Animated and Bitmap Brushes ........................................................307 Paint Dynamics and Using Brushes with a Drawing Tablet ....................................313 GIMP Paint Studio — A Painter-Friendly Batch of Presets ...................................314 Drawing Calligraphic Lines with the Ink Tool ..................................................................315 Working with Gradients .....................................................................................................317 Creating Pattern Fills ...........................................................................................................320 Summary ..............................................................................................................................321 xxii Contents Chapter 12: Enhancing Photos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 Traditional Photographer Tools ..........................................................................................323 Blur/Sharpen ..............................................................................................................324 Smudge ......................................................................................................................326 Dodge/Burn ............................................................................................................... 329 Using Cloning and Healing to Fix Problem Areas .............................................................331 Clone Tool .................................................................................................................331 Perspective Clone Tool .............................................................................................335 Healing Tool ..............................................................................................................338 Using the Exposure Blend Plug-in ......................................................................................341 Summary ..............................................................................................................................345 Part IV: Exploring Filters and Effects 347 Chapter 13: Implementing Blur, Enhancement, and Distortion Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 349 Common Features among Filters ........................................................................................350 Using the Blur Filters ..........................................................................................................353 Blur ............................................................................................................................353 Gaussian Blur ............................................................................................................353 Motion Blur ...............................................................................................................354 Pixelize .......................................................................................................................357 Selective Gaussian Blur .............................................................................................359 Tileable Blur ..............................................................................................................359 Enhance Filters ....................................................................................................................360 Antialias .....................................................................................................................361 Deinterlace .................................................................................................................361 Despeckle ...................................................................................................................362 Destripe ..................................................................................................................... 363 NL Filter ....................................................................................................................364 Red Eye Removal .......................................................................................................365 Sharpen ......................................................................................................................365 Unsharp Mask ...........................................................................................................367 Distortion Filters .................................................................................................................368 Blinds .........................................................................................................................368 Curve Bend ................................................................................................................369 Emboss ......................................................................................................................371 Engrave ......................................................................................................................372 Erase Every Other Row .............................................................................................374 IWarp .........................................................................................................................374 Lens Distortion ..........................................................................................................377 Mosaic ........................................................................................................................378 Newsprint ..................................................................................................................380 xxiii Contents Pagecurl .....................................................................................................................381 Polar Coordinates ......................................................................................................382 Ripple .........................................................................................................................383 Shift ...........................................................................................................................384 Value Propagate .........................................................................................................384 Video ..........................................................................................................................386 Waves ........................................................................................................................386 Whirl and Pinch ........................................................................................................388 Wind ..........................................................................................................................389 Summary ..............................................................................................................................390 Chapter 14: Using Image Creation Filters . . . . . . . . . . . . . . . . . . . . . . 391 Light and Shadow Filters ....................................................................................................391 Gradient Flare ...........................................................................................................392 Lens Flare ..................................................................................................................395 Lighting Effects ..........................................................................................................397 Sparkle .......................................................................................................................400 Supernova ..................................................................................................................402 Drop Shadow .............................................................................................................402 Perspective .................................................................................................................404 Xach-Effect .................................................................................................................404 Lens Effect .................................................................................................................405 Glass Tile ...................................................................................................................405 Noise Filters .........................................................................................................................406 Scatter HSV ...............................................................................................................406 Hurl ........................................................................................................................... 407 Random Pick .............................................................................................................407 RGB Noise .................................................................................................................408 Slur ............................................................................................................................409 Spread ........................................................................................................................409 Render Filters ......................................................................................................................411 Clouds .......................................................................................................................411 Difference Clouds ............................................................................................411 Plasma ..............................................................................................................412 Solid Noise ......................................................................................................412 Nature ........................................................................................................................413 Flame ...........................................