Gimp Tutorial - Free Image Editor Like Photoshop

In this tutorial i will try to introduce you with GIMP, as well as basic usage. I have used GIMP for a long time and it's a good Photoshop replacement for any use(Actually, it's the best image editor after Photoshop that i have ever tried) and the best part is, GIMP is completely free.

GIMP is a high quality freeware application and it's purpose is the creation and editing of graphical contents.

It's primarily created for the Linux operating system, but there are also Windows and Mac OS X versions.

Even though the user interface is similar for all of the systems, i will be describing the Windows interface of GIMP ver. 2.6

You can download GIMP from it's official Website under the Download section, which you can find at: http://www.gimp.org/downloads/

Once you have downloaded, installed, and started GIMP, you can move on to the next step.

The GIMP's interface is complex, and can be set to contain a large number of additional elements.

We will describe the interface with the basic elements needed, which we have split into 7 parts:

1. The main part of the interface which contains the window title(image that we are working on), color settings, number of layers as well as the resolution of the same. Below the Title is a drop-down menu from which we can open, save, create new documents, access different settings, perform various operations. etc.
2. X, Horizontal axis on the virtual ruler.
3. Y, Vertical axis on the virtual ruler.
4. Toolbox part which contains main tools.
5. Toolbox part which contains parameters/settings for the tools chosen above. 
6. "Layers" window contains informations and allows us to do some manipulations with the layers of the active picture.
7. Status bar has the role of showing the state of the picture, while you are performing some operation it will visually indicate the percent of the completion of the operation, unless it's momentarily. On the left side, you have a gray rectangle with "px" with an arrow, as well as a white rectangle that has for eg. "150%" with an arrow. By clicking at the gray rectangle you can choose the unit of the ruler. It's by default set to pixels. The white rectangle shows the "zoom" of the active picture.

The names and the basic descriptions of the tools.

1. Tool for selecting a part of the picture by a rectangle.
2. Tool for selecting a part of the picture by an ellipse.
3. Tool for selecting a part of the picture by freehand or polygons. 
4. Tool for automatically selecting a region by color, we'll call it the Magic Tool.
5. Tool for selecting by colors. It selects regions that share similar colors.
6. Tool for intelligent selecting like Laso, with the difference being it automatically sticks to the contours of the surface.
7. Foreground Select Tool, Laso type tool for selecting objects that are "above", that is on the surface of the picture.
8. Paths Tool, a tool for selecting and modifying curve or polygonal paths which can be later used in multiple ways.
9. Color Picker Tool, a tool for picking the chosen color from the picture for later usage.
10. Tool for setting the zoom level, as well as zooming specific regions.
11. Tool for measuring, you can measure distances and angles with it.
12. Tool for moving layers, selections as well as other objects.
13. Tool for centering - sorting layers or selections relative to other layer or selection, path or the whole image.
14. Crop Tool is a tool for clipping parts of the picture, cropping the picture.
15. Rotate Tool is a tool for rotating layers, selections or paths.
16. Scale Tool is a tool for increasing or decreasing layer size, selection size, or path size.
17. Shear tool is a tool for distorting the image in one way. 
18. Perspective tool is a tool for changing the perspective ot he layers, selections, or paths.
19. Flip Tool is a tool for flipping the layer, selection, or path.
20. Text Tool is a tool for creating or editing layers with text.
21. Bucket Fill Tool is a tool for filling parts of image or selection with a color or a texture.
22. Blend Tool is a tool for filling parts of image or selection with a gradient of colors.
23. Pencil Tool is a tool for drawing with sharp edges.
24. Paintbrush Tool is a tool for drawing with smudged/blured edges. 
25. Eraser Tool is a tool for drawing the back color or turning parts of the image to transparent.
26. Airbrush Tool is a tool for drawing with a changeable pressure of the color it puts. 
27. Ink Tool simulates drawing with ink.
28. Clone Tool is a tool which selectively adds a layer an image to another, from a part of image to another, or from a texture to an image, using a brush.
29. Healing Tool is a tool which "heals" the irregularities of a the picture.
30. Perspective Clone Tool is a tool that does the same as the Clone Tool, except that before adding it does a perspective transformation. 
31. Blur/Sharpen Tool is a brush that blurs or sharpens parts of image.
32. Smudge tool is a brush for blurring parts of image. 
33. Dodge/Burn Tool is a brush for lightening or darkening parts of image.

File | Edit | Select | View | Image | Layers | Colours | Tools | Filters | Windows | Help

Are the drop-down menus that can be found in the user environment of Gimp. Each contains a set of sub-functions which can perform various operations.

• File - Creation of new documents, opening documents, saving documents, printing, closing the program and similar functions.
• Edit - Functions related to copying, cutting, pasting, etc.
• Select - Functions related to selections.
• View - Functions related to the "view" of the working environment. We can set options such as zoom of the image, turn on and off the grid which can help us at positioning and drawing, turn of the ruler from the working environment, etc.
• Image - Functions related to all of the layers of the image. Scaling up or down of all the layers together, rotating all the layers together, changing the color system(RGB, Black and White, Index), etc.
• Layer - Functions related to the creation and handling of individual layers.
• Colours - Functions related to colors. 
• Tools - Tools that can be found in the Toolbox window.
• Filters - Various filters which can be applied to a selection, layer or the whole image. Sharpening, smoothing, cleaning from noises, adding noises, adding fake light as well as other effects. 
• Windows - Here you can find and activate windows like Toolbox, Layers, etc. Parts of the working environment. 
• Help - Informations about usage help.

What are layers?

We can have more layers on our image with different content. One layer can be above or below another, and you can also mix it with the layer below by changing the mode or decreasing the opacity. 

Gimp has a broad range of options that work with colors, and they are all under the Colors menu. We will describe some basic ones.

• Color Balance - Setting the balance between Cyan, Red; Magenta, Green; Yellow, Blue colors.
• Hue - Saturation - Sets the Hue/Saturation of the colors on the image.
• Colourise - Option for changing the color range which will be used in the image.
• Brightness - Contrast - Sets the intensity of the light and the contrast in your image.
• Treshold - Decrease the number of colors to two.
• Levels - Set the color levels.
• Curves - Set the colors with curves or freehand drawn lines.
• Posterize - Decrease the number of colors to a chosen one.
• Desaturate - Turn all of the colors into gray shades.
• Invert - Invert colors.
• Value Invert - Invert the light of every pixel.

If you choose the sub-menu 'Auto' you will find a set of filters for automatic settings of the image:

• Equalise - Contrastsetting
• White Balance - Setting the white color balance
• Colour Enhance - Color setting
• Normalize - Light setting
• Stretch Contrast, Stretch HSV - Stretching the contrast to cover the maximum range.

To get a better idea of how these functions work, and in order to get the "feel" for using them, you will need some time testing them yourself. It's generally a good principle for learning anything in GIMP, because you need more than just reading about tools to know how to use them, you need practice.

This is it for now, the article might be extended in the future. I hope you can find something useful in it.