What is the Gimp

8/6/2019 What is the Gimp

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What Is The GIMP?

GIMP stands forGNU Image Manipulation Program (formerly General Image ManipulationProgram). GIMP is a free graphics editing package. It is typically used to do things like:

Touch up photos Resize graphics

Scan photos

Create logos

Create animated GIFs

Export graphics to web format

...and much more

It's basically a free alternative to Adobe Photoshop. Most of the things you can do in Photoshopyou can do in GIMP.

What Does The GIMP Look Like?

Here's what the GIMP looks like in normal editing view. There are many other dialogs that you

can bring up depending on what your task is, but this is the basic view. We will be looking atsome of the other dialogs later in the tutorial.


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Features & Capabilities

GIMP is loaded with features. If you've ever worked with commerical programs like Photoshop,

you'll be familiar with many of GIMP's features.

Below are some of the main features of GIMP. Don't worry if you've never heard of thesefeatures - we'll be covering many of them in this tutorial.

Painting tools including:o Brushes

o Pencil

o Airbrush

o Cloning tool

o ...and more

Transformation tools including:o Rotate

o Scale

o Shear

o Flip

Selection tools, including:

o Rectangle

o Ellipse

o Free

o Fuzzy

o Bezier

o Intelligent scissors

Layers and channels

Advanced scripting capabilities Full Alpha channel support for working with transparency

Multiple undo/redo (limited only by disk space)

Tile-based memory management, so image size is limited only by available disk space

Sub-pixel sampling for all paint tools for high-quality anti-aliasing

A procedural database for calling internal GIMP functions from external programs, such

as Script-Fu

Support for a wide range of file formats, including GIF, JPEG, PNG, XPM, TIFF, TGA,

MPEG, PS, PDF, PCX, BMP and many others

Plug-ins that allow for the easy addition of new file formats and new effect filters.

Known Platforms

GIMP is the most widely supported image manipulation available. GIMP has been

known to work on the following platforms:


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GNU/Linux

Apple Mac OS X

Microsoft Windows

OpenBSD

NetBSD

FreeBSD

FreeBSD

Solaris

SunOS

AIX

HP-UX

Tru64

Digital UNIX

OSF/1

IRIX

OS/2

BeOS

Furthermore, GIMP can easily be ported to other platforms due to the availability of

its source code.

Installing GIMP

If you use Windows, installing GIMP is usually just a matter of clicking on theinstallation file that you downloaded. Clicking on the file will launch an installation

wizard. You can use the default options or change them as required.


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If you use Mac OS X, you will need to install X11 first. You can get this from your

installation CD. Once X11 is installed, you can install GIMP just as you would with

any other program.

If you use a Unix based system, the Gimp Toolkit (GTK+) and other libraries that

must be installed first. If/once they are, you can compile as a normal user using:

./configure && make and then as root make install. For more info on installing on

Unix systems, check out the official GIMP install help.

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Getting Started With GIMP

GIMP's Main Toolbox

When you open the GIMP, the only thing that appears is a toolbox. The toolbox looks somethinglike this:


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This toolbox is the centerpiece of the GIMP. Most of the time, you'll be using options from this

toolbox.

The main toolbox provides shortcuts to the most commonly used tools in GIMP. The top row

includes selection tools - tools for selecting areas of an image. The toolbox also provides toolsfor rotating an image, scaling an image, adding text, adding color, and more.

Hovering the mouse over an icon will usually bring up a "tooltip" that explains what the tool is

or what you can do with it. Also, in many cases you can press the F1 key to get help about the

tool that you're hovering over.

Creating Your First Image in GIMP

Creating Your First Image in GIMP

Now that we've started GIMP, we have a choice of opening an existing image or creating ourown one. We'll create our own image for now.

We'll create our own little smiley face. Like this:


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Open a New (Blank) Image

To create an image, we first need to open a blank image, or blank canvas. Here's how to do that:

1. Go to File > New...:

2. Choose the size you'd like your image to be. Feel free to select a templatefrom the drop down menu. You can also expand the Advanced Options menufor more options. For the purposes of this tutorial, simply type in the widthand height as shown in the following screenshot:

72 dpi (as shown in the above screenshot) is perfect for displaying your image on a

computer screen (such as on a website). It is also sufficient for printing on a home printer.

If you intend to use your image for commercial printing purposes, you should increasethis value. Commercial printers usually request high resolution images at between 240

dpi and 300 dpi. Beware that by using high resolution images, the file size will become

much larger and it will take longer to download/email etc. To change the dpi value, clickon "Advanced Options" and change the resolution.

3. Click OK

You will now see a blank, untitled image. It looks similar to say, a blank word processing

document.

Well, our blank image may looklike a word processing document, but it doesn't act like one!


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With our blank image, we have the ability to manipulate every single pixel. We can type text,

paste photos, create a drawing, and much more. But more importantly, we have total control over

where everything goes.

Anyway, let's create a basic picture for now.

Image Composition

Our smiley face image consists of a bunch of circles, a straight line, and a curved line.

To do this, we use a combination of the following tools:

The Ellipse selection tool The Paintbrush tool The Pencil tool.

Here's how we do it.

The Face Outline

First, let's create the face outline. It's basically a circle, so we can use the Ellipse selection tool.

1. Select the Ellipse selection tool. To do ths, click the Ellipse icon from the maintoolbar. The Ellipse icon looks like this:

2. Now click and drag within the image area (also known as the "Canvas"). This

will create a circular selection area, highlighted by an animated dotted line(also known as "marching ants"). For best results, start somewhere near thetop-left corner, and release near the bottom-right corner. Your selectionshould look something like this:


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You can see by the above screenshot that the image is being displayed at its full size (the

text "100%" is being displayed under the image). You can zoom in and out by clicking

the down-arrow. Alternatively, you can select View > Zoom.

3. Now we will create a thick black line around our selection. To do this, selectEdit > Stroke Selection...

4. A dialog box will pop up. Set the stroke width to 6 px and ensure that LineStyle is set to "Solid".

5. Click OK

You should now see a black line in the shape of your selection. Your image should look

something like this:


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You may notice that the "marching ants" remain on your selection. This is because the selection

still exists (in case you need to do anything else with your selection). Before you continue to thenext step, you should remove the selection. To remove the selection, select Select > None (or

keyboard shortcut: Shift+Ctrl+A).

Your line may be a different color. This will depend on what color is selected as the foreground

color on your main toolbox. If white is selected, you won't see your stroke (because the

background is also white). If this is the case, you will need to change the color. You can do thisby clicking on the foreground color and changing it. The foreground color is the black part on the

left side of the color area. Here's a screenshot of the color area:

If you have trouble changing the foreground color, there's a more detailed explanation on ourlesson foradding color.

The Eyes and Nose

We will now create the eyes and nose. We will do this with the paintbrush tool.

1. Select the Paintbrush tool. To do this, click the Paintbrush icon on the maintoolbox. The paintbox icon looks like this:

2. Now make two dots (where the eyes should be). To do this, simply click onthe image where you want the eyes to be. If you make a mistake, you can

always "Undo" (Ctrl+Z

) then try again.3. Now draw a line where the nose should be. You do this by clicking anddragging. Again, if you make a mistake, Ctrl+Z will undo it.

At this stage, your image should look something like this:
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Now for the mouth.

The Mouth

For the mouth, we will use a more advanced tool. We will use the Path tool. This tool allows us

to create smooth curves.

You may be wondering why we don't just use the Paintbrush tool for the mouth? Well, feel free

go ahead and try! You'll find that it's extremely difficult getting the curved line to look nice andeven while using the paintbrush tool.

The Path tool on the other hand, allows you to create a nice, smooth curve.

I should mention that the Path tool can take a bit of getting used to. It's not as easy to use as the

Paintbrush tool. But I recommend practicing with the Path tool as it will give you much more

control over your image compositions.

1. Select the Path tool. It's the one that looks like this:

2. Click where the right corner of the mouth should be.3. Now click and drag, starting from where the left corner of the mouth should

be. You need to drag to the right, and slightly up. You will see a path formingin the shape of the mouth. The path forms between your two anchor points.

You will also see some levers with handles that enable you to change theshape of the path. Move the mouse around until you're happy with the shape.

Then you can release the mouse. Here's what it should look like so far:


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4. Now for the stroke. Select Select > Stroke

5. When the dialog box pops up, click OK. This is the same dialog box thatpopped up before when we created the stroke around the face. For now, we'llleave the stroke at the same setting as before (6 pixels and solid).

Your face is now complete. It should look something like this:

When you create a path, it is automatically saved so that you can use it again later. You can viewyour saved path by opening the Path dialog box (Dialogs > Paths).

Don't worry if you don't quite understand paths right now, we'll be covering them in more detail

later.

Saving Images in GIMP

So you've created your first image in GIMP. Now what?

You should save your image (before something happens and you lose your 2 minutes of hard

work!)
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When saving images, you need to decide which format you want to save the image in. Of course,

there's nothing stopping you saving multiple copies of the image, each in a different format. In

fact, I recommend keeping multiple copies of your image - especially if you are doing a lot ofwork on it.

In any case, you still need to understand which is the best format to use.

Saving Your Image

In GIMP, the way you specify an image's format is to save it with the applicable extension.

For now, we'll save our image in XCF format (GIMP's native format). It's a good idea to have atleast one copy of your image in native GIMP format. You might even create multiple copies,

each at different stages of modification.

1. Select File > Save As...

2. Once the dialog box pops up, enter the image name ensuring you use a .XCFextension. Alternatively, you can expand the "Select File Type" node to selectyour preferred file type. You can also expand the "Browse for other folders"


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node to choose which folder to save the file into.

3. Click Save

Depending on the file format you use, you may see another dialog box where you can

enter values specific to the file format. In this case, you can either use the default values

or adjust settings as required.

About .XCF Extension

GIMP's native format uses a .XCF extension. This is the best format to use if you intend to

modify the image in the future. By saving your file with a .XCF extension, you ensure that all

image data (such as layers, channels, paths etc) is saved exactly how you created it. When youopen it up again, you can continue from where you left off.

Note that only GIMP recognizes the XCF format - you will only be able to open XCF files with

GIMP.

Saving For Web

There are two very important things to remember when creating graphics for the web:

Keep the file size down Use the correct format

File Size

Graphics have the potential to be really big. I mean really big. The problem is that, if you don't

know what you're doing, you might not notice how big the file size is. The graphic may look


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small on the screen but, if it's using a high resolution, its file size could be much larger than you

need it to be. This could result in the image taking too long to download for your users to view.

Check that the image is using a resolution of 72 dpi. Assuming that it is 72 dpi, when you viewthe image at 100% zoom, it should be the correct size.

Also check that you're using the correct color mode (i.e. RGB, grayscale). Color images should

be RGB. Black and white should be grayscale. To check this, go toImage > Mode. The current

mode will be grayed out.

Correct Format

If you intend to use your image on a website or blog, you will need to save it in a format that

web browsers recognize. The most common file formats to use for the web are GIF, JPEG, andPNG.

In general, JPEGs are best for complex images with lots of colors (such as photos). GIFs on theother hand, are better for images with flat colors (such as cartoon illustrations, logos etc). For

more information on the difference between GIFs and JPEGs, see GIF vs JPEG.

Other Supported Formats

GIMP supports many different file formats. You can see these formats whenever you save a file

and expand "Select File Type" (as in the screenshot above).

The next lessoncovers the file formats supported by GIMP.

GIMP File Formats

Now thatyou've saved your image in XCF format, here's a list of the other image formats that

GIMP supports.

Don't worry about memorizing these just yet! When it comes time to save your images, the main

image formats for the web are JPEG, GIF, and PNG. For print you'd be looking at EPS or TIFF,and maybe PSP (if you're exchanging images with a designer who has Adobe Photoshop). Of

course, if you're saving for print, you'd need to ensure that your images were created at a high

enough resolution. But that's another lesson!

Popular File Formats

These file formats are well known and their usage is quite widespread.
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File

FormatExtension(s) Description

XCF

.xcf/

.xcf.gz/.gz/.xcfgz/

.xcf.bz2/.bz2/.xcfbz2/

.gbr/.gih/.pat

GIMP's native format which will preserve all image data,including layer, the current selection, channels, transparency,

paths and guides. Note that it doesn't save undo history.

XCF images take up a lot of disk space, and are not

supported by most image viewers, which is why XCF ismore suitable for saving images for future editing (rather

than image exchange).

If you must exchange a XCF file, you can use the compressoption, which uses either gzip (using xcf.gz/gz/xcfgz

extension) or bzip2 (using xcf.bz2/bz2/xcfbz2 extension)

compression.

Other GIMP's native format includes GIMP Brush (.gbr),GIMP Animated Brush (.gih), and GIMP Pattern (.pat).

BMP .bmp/.dib

Bitmap is an uncompressed image format, which is the

internal image format for Windows and OS/2 Graphic

Subsystem.

GIF .gif

Graphic Interchange Format is often used for screenshots

and computer graphics. It is lossless if the image has under

256 color or otherwise it become lossy.

The GIF format allows transparent mask, which means apixel can only be fully transparent or fully opaque, and not

partially transparent.

HTML .htm/.html

Hypertext Markup Language. GIMP will save an HTMLpage with the image represented by an HTML table. Each

table cell represents a different pixel in the image.

Hexadecimal colors are used in order to apply colors to each

cell.

ICO .ico Icon Image File Format is Windows' image format for icons.

JPEG .jpg/.jpeg/.jpe

Joint Photographic Experts Group is typically used for

photographs. JPEG uses lossy compression that results in aloss of detail, commonly called artifacts. The artifacts are

usually most noticeable on images that have sharp edges,

while less noticeable on photographs, which have manysmooth gradients.

PNG .png

Portable Network Graphic is often used for screenshots and

computer graphics. It uses lossless compression. It allows

full alpha transparency.

PNM .pnm/.ppm/.pbm/

.pgm/.pam

Portable Pixmap. PNM (Portable Any Map, a shorthand for

ppm, pbm, and pgm format), PPM (Portable Pixel Map),


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File

FormatExtension(s) Description

.pbm (Portable Bit Map), .pgm (Portable Gray Map) and

.pam (Portable Arbitrary Map).

PS and

EPS.ps/.eps Postscript Document and Encapsulated Postscript

PSD .psdPhotoshop Document, the native format of another popular

graphic editing software, Adobe Photoshop.

TGA .tga Truevision Graphics Adapter, Targa's native image format.

TIFF .tif/.tiff Tagged Image File Format

XBM .xbm X Bitmap 2-bit, Monochrome Bitmap for X Window System

XPM .xpm X Pixelmap Color Bitmap for X Window System

Less-Popular File Formats

The GIMP also supports the following, less popular, file formats.

Extension(s) Description

.pix/.matte/.mask/.alpha/.als Alias/Wafefront Pix Image

.fli/.flc Autodesk FLIC Animation

.c/.h C/C Header Sourcefile Format

.dcm/.dicom Digital Imaging and Communications in Medicine Image

.fit/.fits Flexible Image Transport System

.cel KISS Cel

.sgi/.rgb/.bw/.icon Silicon Graphic IRIS Image

.im1/.im8/.im24/im32/.ras/.rs SUN Rasterfile Image

.pcx/.pcc ZSoft PCX Image

.xwd X Windows Dump

Limted Support

The GIMP can read, but not write, files in the following formats.

Extension(s) Description

.g3 G3 Fax Image

.wmf/.apm Microsoft WMF File

.psp/.tub Paintshop Pro

.pdf Printable Document File

.svg Scalable Vector Graphic


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GIMP Selection Tools

When we created our first image, we used the Ellipse tool. The Ellipse tool is from a group of

tools known as selection tools.

Selection tools are an essential part of GIMP. You'll find that many tasks you perform in GIMPwill involve a selection tool.

What Do Selection Tools Do?

Selection tools enable you to select exactly which part of the image you want to work with.

Once you make a selection, anything you do will apply only to that area (the area that the

selection covers). This is essential when building shapes (like the smiley face from our previouslesson). It is also essential when selecting objects from photos.

When you make a selection, the selection is made against the current layer. We'll cover layers

soon but, basically layers allow you to break your image up into separate parts - all stacked upon

each other.

I highly recommend becoming familiar with the various selection tools. There are different

selection tools for different situations. Choosing the right tool for the job can save you a lot of

time.

Example

Take the following photo for example.

In this photo, most of the hill has been selected. You can tell because "Marching Ants" follow

the edge of the hill. The lighthouse, the ocean, and the sky are not selected.
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This selection was made using the Fuzzy Select Tool - otherwise known as the Magic Wand. The

Magic Wand works based on color similarity. It selects parts of the image that are similar in

color to the area you click in.

So now that the hill has been selected, our work on the image will only apply to the hill. For

example, if we grabbed the Brush tool and drew a big line through our image, it would onlyaffect the part where the selection is. Perhaps a more realistic task would be to adjust the colors

or brightness of the hill. Another thing we could do is copy the hill and paste it into anotherimage. We could also add the lighthouse to our selection.

Creating A Selection

The way you create a selection will depend on the selection tool that you use. Some require you

to click and drag. Some require you to click various parts of your image in order to indicate theselection area. Others simply require a single click. Most are reasonably intuitive.

The table further down in this lesson outlines each tool and how to use it.

"Deselecting" A Selection

Once you've made a selection, it will usually stay there, waiting for you to do something with it.If you decide that you don't need the selection, you can remove it.

You can remove/deselect an active selection by going to Select > None, or using the keyboard

shortcut ofShift+Cntrl+A.

Another way of removing an active selection is by clicking outside of the selection (while stillhaving a selection tool selected).

Modifying A Selection

You can modify an active selection by holding the Shift key down while modifying the

selection. If you don't hold this key down, you will wipe your existing selection and create a newone.

You can also add to existing selections by using a saved path or channel. More on saved paths

and channels below.

Saving A Selection

Selections are generally temporary - once you "deselect" a selection it's gone forever. Once youdeselect a selection, you will need to make your selection again.


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Having said this, if you think you might need to use the selection again in the future, you can

always save it as a path or channel.

To save as a path, use the Save to Path option. Once it has been saved as a path, you can reloadthe selection from within the Path dialog box by right clicking on the path and selecting Path to

Selection).

To save your selection as a Channel, use the Save to Channeloption. You can reload the

selection from within the Channel dialog box by right clicking on the channel and selectingChannel to Selection.

The Selection Tools

Let's have a quick look at the various selection tools, what they do, and how to use them.

Icon Tool Description

RectangleSelection Tool

Selects an area in the shape of a rectangle. Simply click and drag to createa rectangular selection. The selection is made once you release the mouse.

Ellipse

Selection Tool

Selects an area in the shape of an ellipse (a circular shape). Simply click

and drag to create an elliptical selection. The selection is made once yourelease the mouse.

Lasso SelectionTool

Allows you to draw a selection free-hand with your mouse or other

pointer. When you release the mouse button, the selection is closed by

connecting the current pointer location to the start location with a straightline. You can go outside the edge of the image display and come back in if

you want to.

Fuzzy SelectTool (Magic

Wand)

Enables you to make a selection, based on contiguous areas of a similarcolor range. The color range is determined by the point at which you click

on and the value of the Threshold(within the Tool Options dialog).

Select By Color

Tool

Allows you to select areas of an image with a similar color range. Thedifference between this tool and the Fuzzy Select tool, is that the fuzzy

select tool selects contiguous pixels - those that are next to, or close to,

each other. The Select By Color Tool, on the other hand, selects all pixels

within the color range, regardless of their location on the image.

IntelligentSissors

This tool is useful when you are trying to select a region defined by strong

color-changes at the edges. To use the Intelligent Scissors, you click to

create a set of "control nodes", also referred to as anchors or control points,

at the edges of the region you are trying to select. The tool produces acontinuous curve passing through these control nodes, following any high-

contrast edges it can find.

Note that this tool doesn't always produce a nice, smooth path. Manyexperienced GIMP users tend to use the Path tool instead.

Path Tool Technically, this tool is not a selection tool, however it creates paths -

which can be turned into selections. This tool allows you to draw around


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Icon Tool Description

the edge of any object on your image. More importantly, it provides you

much more control than the other selection tools when working withcomplex shapes. Similar to the Intelligent Sissors, the Path tool results in

control points that you can move around as required.

Foreground

Select

The Foreground Select tool was released in GIMP version 2.4. Using thistool is done in two steps. First, you make selection which contains the

entire object. Then you paint over the selected area with a brush, not

crossing objects border. Release mouse button when youre done and lookto see if there are dark blue spots on your objects. If there are some, paint

over them with a brush again and release to refine the selection. When

there are no more blue areas inside the object, press Enter and your object

will be selected.Reference:

http://www.quackit.com/web_graphics/gimp/tutorial/gimp_selection_tools.cfm

Documents

What is the Gimp