Transcription
Getting Started with
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Table of ContentsAbout This Tutorial.5Organization .5Assumptions .6Conventions.6The GIMP Basics.7Working with Image Files.7Working with Layers .8Working with Filters .9Working with Color .9Getting Started .11Starting the GIMP.11Creating a New File .16Opening a File .17Using Undo .18Saving a File.19Exiting the GIMP.21Creating a Pencil Sketch from a Photo .23Index .30Table of Contents3
About This TutorialThe GIMP (GNU 1 Image Manipulation Program) is a free program to create and edit digitalimages. You can use the GIMP to touch up photos, lay out web pages, make digital art,produce logos, create animations, and perform many other useful and creative graphicfunctions. The shadow effect used on the cover title and the screen shots used throughoutthis tutorial were produced using the GIMP.The GIMP is available for the Linux, Unix, Windows XP, and Mac OS X operating systems.This tutorial gives an overview of some basic digital editing concepts and shows you how toget started using the GIMP.This tutorial gives you a brief introduction to some digital editing concepts, shows you howto perform basic GIMP operations, and leads you through an example.The digital editing concepts — working with image files, layers, filters, and color — areexplained and then demonstrated in the example that follows. The example gives step-bystep instructions for creating a pencil sketch or drawing from a color photo.OrganizationThis tutorial contains these sections: The GIMP Basics: a brief discussion of working with image files, layers, filters andcolor. This background is presented to enable you to understand the instructionsthat come later; it is not a thorough treatment of these topics. Getting Started: step-by-step instructions for starting and exiting the GIMP,opening and saving files, and using the GIMP undo function. Creating a Pencil Drawing: step-by-step instructions for creating a pencil drawingfrom a photo so you can practice using the GIMP’s digital editing features.1GNU (pronounced g-noo) refers to a project called “GNU’s Not Unix” that produced thefree software operating system called Linux. The Gimp was first distributed with Linux butis now available for other platforms as well.About This Tutorial5
AssumptionsThis tutorial makes two assumptions about your readiness to begin using the GIMP: This tutorial assumes you have the GIMP already installed on your computer. If youdon’t, check the system requirements and follow the download and installationinstructions found on the GIMP website http://www.gimp.org This tutorial assumes you have a photo already loaded onto your computer. If youdon’t, these are some of the ways you can get one: upload a photo from your digitalcamera, import a picture using a digital scanner, download an image from the web2,or ask a friend to email you a photo.ConventionsThe step-by-step instructions for the examples in this tutorial use these conventions:Instruction:Action:ClickClick the left mouse button.Double-clickClick the left mouse button twice inrapid succession.Right-clickClick the right mouse button.Ctrl-KeyPress the Ctrl key and the indicated keysimultaneously.2Because images on the web may be subject to copyright, get permission from the image’s creatorbefore using one.6Getting Started with The GIMP
The GIMP BasicsBefore you begin using the GIMP, it’s helpful to understand some common digital editingterms and concepts.This section is designed to give you a basic understanding of working with images, namely,working with image files, layers, filters, and color. There are many other important aspects toworking with images, but these are the ones most relevant to creating the effectsdemonstrated in the example and are enough to get you started using the GIMP. A completediscussion of these topics is beyond the scope of this tutorial, but can be found in manybooks, articles, and other references pertaining to digital graphics editing.The best way to learn the GIMP is to go through a step-by-step example like the one in thistutorial, then experiment on your own.Working with Image FilesDigital images are stored on your computer using special file formats. The most commonlyused file formats are GIF and JPEG, and to a lesser extent, PNG. Generally speaking, thedifferences among them have to do with the number of colors, level of detail, and types ofimages they can handle, and whether or not they are widely supported by the major internetbrowsers. Other technical considerations such as file compression play a role too.JPEG files are used for storing images with lots of color and detail like photos, while GIFsupports drawings and simple artwork that use fewer colors. GIF is the standard image fileformat for the web. JPEG files can be used as well, but they tend to be larger and takelonger to load into your browser.PNG is a newer file format that improves upon GIF and will grow in popularity as browsersupport increases.The GIMP Basics7
The GIMP works with these, and many more, files types:File TypeGIFJPEGPNGFileExtension.gif.jpg.pngColors8-bit (256 orfewer colors)24-bit (millions ofcolors)8-bit, 24-bit, or32-bitBestsuited for:Flat colorimages, line art,andtypography.Continuous tonegraphics,photographs, andanything with softand blurry edgesFlat colorimages, lineart, andtypographyBrowserSupportWidelysupportedWidely supportedEmergingThe GIMP supports dozens of other file types besides the three mentioned here. The GIMPhas its own file type called GIMP XCF. If you are working with a file and want to save it andcome back to it later, GIMP XCF is the file format you should use because it preserveslayers. (Layers are explained in the next section.) When you have finished your work, you canexport the image to a different format.Working with LayersYou can think of a layer as a single transparency or sheet of acetate on which you can drawor paint. Layers are stacked on top of one another, and each layer can affect the look of thelayers below it. In digital editing, layers are used to separate the elements in an image so youcan work on one part of an image without affecting the rest. For example, by using layersyou can adjust the color in one part of your image without disturbing the color anywhereelse.8Getting Started with The GIMP
You can make a layer completely transparent — revealing the layers below it — or opaque,which keeps the layers below it hidden. You can vary the level of transparency too so that alayer can influence how much of the layers below are revealed.Blending modes offer a way to combine layers. A blending mode (or mode) is a rule thatdescribes how the lower layers are treated with respect to the active layer (the layer you arecurrently working with). In the pencil drawing example instructions on page 23, two modesare used: Dodge mode: enhances the detail in the darker parts of the image. Multiply mode: provides an effect like that of looking at the image through tintedglasses.Working with FiltersAs in real photography, digital imaging filters allow you to adjust lighting for your pictures.Using the GIMP, you can add or filter out light or apply shadows to your images.The GIMP has dozens of filters. Among them is the Selective Gaussian Blur which allowsyou to blur the background of an image in order to make the foreground stand out. Thisfilter is used in the example given later in this tutorial.Working with ColorYou can use the GIMP to create color artwork, color-correct a photo, or change a colorimage to black-and-white or grayscale. You can enhance your images by making subtleadjustments to hue, luminosity, saturation, and contrast. You can invert colors, so that colorsare replaced by their color complements (in grayscale, black is swapped for white and viceversa), and you can add texture and patterns. If you wish, you can remove color completely.The GIMP Basics 9
Getting StartedThis section tells you how to start the GIMP, create a new file, open an existing file, use theundo function, save a file, and exit.Starting the GIMPTo start the GIMP from your desktop, double-click on the GIMP icon.Getting Started11
The GIMP splash window briefly displays while the GIMP starts.After a couple of seconds or less, three windows are displayed: the GIMP ImageManipulation Program window (hereafter referred to as the main window), the Toolbox, andthe Layers dialog.The main GIMP window is where your image is displayed. If you open more than one imagefile at a time, each will be displayed in its own main window. If you are creating a new imagefrom scratch, the main window provides a blank canvas (working area) on which you candraw or paint.12Getting Started with The GIMP
The main window contains the menu options that provide the operations you’ll need towork with your image.The Toolbox contains selection tools (operations that allow you to select parts of your imageto work with) and transformation tools (for example, operations to move or rotate youimage) and controls for using color.Getting Started 13
14Getting Started with The GIMP
The Layers dialog provides controls for managing layers. It displays the layer stack andindicates which layer is the active layer. From here you can adjust transparency, make yourlayers visible or invisible, and apply blending modes.The controls in the Toolbox and the Layers Dialog are also available as menu options on themain window.Getting Started 15
Creating a New FileFollow these instructions to create a new image file:1. Using the main window, click File New.2. In the Create a New Image dialog, type values into the Width and Height fields, selectthe unit of measurement from the adjacent drop-down list, and click OK. When indoubt, specify your image dimensions in pixels.16Getting Started with The GIMP
Opening a FileFollow these instructions to open an existing file on your computer:1. Using the main window, click File Open. The Open Image dialog appears:2. Under Places, click on a place in your computer where your image folders are located.The GIMP will display the list of folders under the Name heading. Alternatively, youcan use the top row of buttons to locate folders.Getting Started 17
3. Double-click to select a folder and keep selecting folders until you have located yourimage file. (You may have to repeat selecting folders if you use subfolders.)4. Click on the image file (the image will appear in the Preview area of the dialog), thenclick Open. The GIMP will display your image in the main window.Using UndoFor all practical purposes, the GIMP supports an unlimited level of undo. This means thatshould you want to back out an editing operation, revert to a previous version of your image,experiment with effects, or simply correct a mistake, you can do so easily.To undo the last operation, click Edit Undo in the main window.18Getting Started with The GIMP
Saving a FileIf you have opened an existing file and want to save your image in the same file, click File Save.If you want to save your image in a new file, follow these instructions:1. Using the main window, click File Save As. The Save Image dialog appears:Getting Started 19
2. Under Places, click on a place in your computer where you image folders are located.The GIMP will display the list the folders under the Name heading. Alternatively, youcan use the top row of buttons to locate folders.3. Double-click to select a folder and keep selecting folders until you have located the onein which you want to save your image. (You may have to repeat selecting folders if youuse subfolders.)4. In the Name field at the top of the menu, type in a filename including the file extension(.jpg for JPEG or .gif for GIF), and click Save.5. Depending on which file extension you type, another dialog will display. In either case,click Save.20Getting Started with The GIMP
Exiting the GIMPTo exit the GIMP, click File Quit. If you have open unsaved files, you’ll be prompted tosave the files or to discard the changes before the GIMP exits.Getting Started 21
Creating a Pencil Sketch from a PhotoThis section gives step-by-step instructions for creating a pencil sketch from a photo. Thisexample demonstrates the use of layers, blending modes, color, and filters.Before you begin, choose a color picture or photo that already resides on your computer.This example starts with the following image:Creating a Pencil Sketch from a Photo 23
Follow these instructions to turn a color photo into a pencil drawing:1. Start the GIMP, open your image file (see page 17), and click Layer DuplicateLayer. The GIMP creates a new layer called “background copy” and makes it visible inthe Layer window.Alternatively, you can accomplish the same step using the Layers dialog. The layer stackcontains a row for each layer, represented as thumbnail images. (The eye icon indicatesthat the layer is visible.) Right-click on the top layer, then from the pop-up menu clickDuplicate Layer.24Getting Started with The GIMP
2. Using the main window, click Colors Colorize. Using the Colorize dialog, slide theSaturation control all the way to the left until the value shown in the field next to it iszero, then click OK. The GIMP removes the color from the active (top) layer, leavingyou with a black-and-white version of your image.Creating a Pencil Sketch from a Photo 25
3. Using the main window, click Layer Duplicate Layer, then apply a filter to give theimage a blurred effect. Click Filters Blur Selective Gaussian Blur, and using theSelective Gaussian Blur dialog, check the preview checkbox, type 5 into the Blur radiusfield, type 50 into the Max Delta field to the right of the slider, and click OK.26Getting Started with The GIMP
4. Using the main window, click Colors Invert. The black pixels turn white, and thewhite pixels turn black, giving the image the appearance of a film negative.Creating a Pencil Sketch from a Photo 27
5. Using the Layers dialog, change the opacity value to 50%. You can do this in one of twoways: use the mouse to drag the slider until 50 appears in the field beside it, or type 50directly into the field. The image in the main window will show very faint lines against agray background.6. Using the Layers dialog, position your mouse on the top layer and right-click. Using thepop-up menu, click Merge Down. The GIMP merges the top two layers so you nowhave two layers instead of three.7. Apply the first blending mode to the image: Using the main window, click Layer Duplicate. Using the Layers dialog, select Dodge from the Mode drop-down list at thetop of the dialog. Using the main window, click Layer Merge Down.28Getting Started with The GIMP
8. Apply the second blending mode to the image: Using the main window, click Layer Duplicate. Using the Layers dialog, select Multiply from the Mode drop-down list.Using the main window, click Layer Merge Down.9. Save the image into a new file (see page 19).Creating a Pencil Sketch from a Photo 29
IndexAIactive layer, 15installing the GIMP, 6BJBlending modes, 9JPEG, 7CLcanvas, 12color, 9creating files, 16layersactive, 15definition, 8managing, 15Layers dialog, 15Linux, 5Ddigital editing, 7Dodge mode, 9download, 6MEexiting the GIMP, 21Mac OS, 5main window, 12managing layers, 15Multiply mode, 9FOfile types, 8filescreating, 16extensions, 20opening, 17saving, 19types of, 7opacity, 28opening files, 17operating systems, 5GGIF, 7GIMP icon, 11Ppencil sketch, 5PNG, 7Qquitting the GIMP, 19
SUsaving files, 19selection tools, 13Selective Gaussian Blur, 9splash window, 12starting the GIMP, 11system requirements, 6undo, 18Unix, 5TXToolbox, 13transformation tools, 13XCF, 8WWindows XP, 5Creating a Pencil Sketch from a Photo 31
The GIMP is a GNU Image Manipulation Program.It is freely distributed software.0820-6371188
About This Tutorial . The GIMP (GNU. 1. Image Manipulation Program) is a free program to create and edit digital images. You can use the GIMP to touch up photos, lay out web pages, make digital art, produce logos, create animations, and perform many other useful and creative graphic functions.
