CHAPTER 2 : INTRODUCTION TO GRAPHISM AND GIMP 2



Used software : GIMP 2

On your two bmp images you' ll can use many tools GIMP 2 offers to you, but i's not so easy to begin with, that's why this chapter 2 exist. We firstly will focus on a description of the different types of bmp images and in a second time we will see some graphism notions et and a quick explanation of the GIMP 2 interface bases. Like that you'll enter in the chapter 3 with a quite good knowledge about graphism and GIMP 2 and you will not be too much disturbed when opening your bmp image under GIMP 2.


1/ ABOUT THE BMP IMAGES

N.B. : the bmp images you just get are bmp Indexed Color images.

1.1 bmp Indexed Color images

The bmp indexed color images have a palette limited to 256 colors or less and are made of one layer, these are « simple » images who need low memory. These images all get a color palette it's why they are called indexed colors images, the different colors (or tints) of your image are indexed (numbered) from 0 to 255.
You can't use the tools of the color menu on that kind of bmp images.

1.2 RGB bmp images

The RGB bmp images have no color palette and so they're not indexed. You can use the tools of color menu on that ones.


2/ BASIC NOTIONS TO BE MASTERED

Before going further, you have to understand involvements and differences between tints, saturation, contrast and luminosity/value

Hue/Tint : it's the color in its proper sense composed by a mix of the three basic colors Red , Green and Blue, there is 256 basics tints. But you can create 16 billions different colors (or tints) by mixing RGB colors with the color balance.

Saturation : it's the density, the wealth in color of your pixels, the saturation get from 0 (white) : maximum poverty in color to 255 (pure color) : maximum wealth of color.

Contrast : go towards clear tones or dark tones.

Brightness/Luminosity/Value : stand for the level of luminosity, the brightness of a color. The value gets from 0 (black) to 255 (pure color).


3/ THE GIMP 2

The GIMP 2 gives you loads of menus, options and tools for make your dreamed colorization. I am going to make for you a small description of the GIMP 2 interface, the Toolbox and the Colors Menu, so that you will not be confused when you will open your image under GIMP 2.

3.1 GIMP 2 interface

GIMP 2 interface : Window and Toolbox

>>> A working Window and a Toolbox with at the top tools, below tabs.

- In the top of the Toolbox there are tools and in the bottom tabs.

- You can open a new window for every used tool or place them in tabs (by opening a tab Option of tools) in the Toolbox what is more practical, particularly if you have to juggle between several tools and several tabs.

3.2 The Toolbox

- The Tools :

Selection by Color : allows you to select zones by colors, according to several flexible parameters.

Magic Wand : (Tool of akin selection) same thing that the color selection by color but by zones of nearby pixels.

Brush : to paint, very usefull in particular with the overlay setting who allows you to modificate and make subtle color changes to different parts of the item.

Freehand Selection : allows you to select a zone like you wish and you need which can be really usefull.

- The Tabs :

The Tabs allow you to organize better your workspace.

To open a new tab click on >>> Layers >>> Add Tab and chose the ones you need.

Personally i use especially tabs Option of tools, Timekeeper, Palette of the indexed colors and Palettes. The Tab "Option of tools" can be set for make appear the tool that you're currently using, this tab updates each time you change your tool.

Tabs for a good organization of tools

>>> Layers >>> Add Tab

3.3 Colors Menu

N.B. : to use these options your bmp images as to be in RGB Mode.

Colors Menu options

>>> In this menu there are five options which will interest us particularly.

Color Balance : Compose a color or tint from nuances of Red, Green and Blue.

Hue-Saturation : change the color and his density.

Colorize : transform the selection into black and white image in which we stack a color.

Brightness-Contrast : Modify the value of pixels, mean darkening or clearing up.

Desaturate : mean deleting all the color, it remain only the values : nuances of black, white and grey.


>>> Now that you know more about basic notions of graphism and GIMP 2, you can go to the Chapter 3 !!!