Lesson 18: Advanced color tools

The color palettes

GIMP comes by default with 40 color palettes. To access them, guess what, you go with Windows > Dockable Dialogs > Palettes. You know how to use dockable dialogs in GIMP. You can preview clicking on an icon, and by rightclicking you can edit a palette, you can create a new one, you can import, you can duplicate, you can delete (not the defaults, though), and you also have some other interesting commands. Editing a palette, you get an extra window named "Palette editor", where by clicking a color you set it as foreground color or by CTRL+clicking you set background color. At the bottom of the Palette Editor you have buttons to save, create new, edit, delete. You can resize this window and control the zoom. By rightclicking on a color you have some handy commands.

Palettes files are saved somewhere, apparently. Check Edit > Preferences > Folders > Palettes. Things are easier than with the fonts case described in the previous Lesson. You can find free ".gpl" files and put them right there. These files are simple textfiles which you can even edit directly. After these actions, you must rightclick inside the Palletes Dialog and give the command Refresh Palettes to use the new palettes data at once.

Creating a palette from image data

Let me say, you see a webpage with some interesting colors and you want to pick them in the GIMP as a palette. Through a screenshot, you create a new image. You make a (multiple, if needed) selection on the interesting parts. Rightclick inside the Palettes Dialog, and Import Palette.... With this fantastic dialog, you can select as a source the whole image, or the selection, with "Sample Merged" you can define if you want all active layers taken into account, you can set the number of colors, and with "Interval" to set the step, and even having a quick preview of the palette to be created.

The Color Picker Tool

Selecting this one on the Toolbox, you can select colors - from your opened images or not:

• Inside GIMP: activate the layer you want, zoom, click.
• Outside GIMP: take a screenshot (Printscreen or Alt+Printscreen), in GIMP File > Create > From Clipboard (CTRL+SHIFT+V), zoom, click.

The Color Picker Tool has interesting options:

• Sample average: you do not pick a single pixel but you define the size of the sampling area.
• Sample merged: all enabled layers are taken into account, otherwise only the currently active one.
• Pick mode: 'Pick only' makes sense if you have 'Use info window' checked (no selecting action happens). 'Set foreground color' sets your selection as foreground color. 'Set background color', OK you know what. 'Add to palette' adds your selection to the currently selected palette.
• Use info window (Shift): you get a nifty helper window presenting the actual numerical color data of your clicks. You guess right, this option can be checked on the fly with the SHIFT key down.

The Colors dockable dialog

Windows > Dockable Dialogs > Colors. Think of it as another instance for the foreground/background color selection dialog. Since the typical foreground/background color selection dialog is resizable, i personally find no reason in this dialog except from being dockable on the Toolbox.